This document summarizes a numerical simulation study of gas turbine blade tip cooling. The study models a two-pass serpentine cooling channel inside the blade with and without pin fins on the tip surface. It was found that providing pin fins at the tip surface can increase heat transfer by up to 1.3 times compared to a smooth surface, with pressure drop increasing by less than 6%. Proper placement and number of pin fins is recommended for enhancing heat transfer and cooling of the turbine blade tip.
Rib roughened cooling passages for turbine coolingDevi Archana Das
In modern gas turbine engines, the continuous increase of power for an expected lifetime has resulted in a continuous increase of cycle pressure ratio and turbine inlet temperature. The later implies that advanced materials and cooling techniques must be adapted for a safe operation of the high pressure gas turbine blades and vanes. This need for high power and high efficiency gas turbine engines forces the designer to continuously increase the turbine inlet temperature. In recent military applications, the turbine inlet temperature could be as high as 2000K, far above the melting temperature of the most advanced vane and blade materials. Thus apart from the progress made in the metallurgical domain, a continuous cooling of blade of turbine 1st stages allows operating at temperatures which are far above material’s melting point without affecting component integrity and geometry. The efficiency of the blade cooling system is therefore strictly related to the safe operation of the engine and complete understanding of the convection mechanisms resulting from the cooling techniques is mandatory.
The most common internal heat transfer enhancement methods of heat transfer augmentation in gas turbine airfoils are ribs, pins, jet impingement, and flow disturbing inserts.To maintain the flow inside the cooling passage of turbine blade turbulent all these methods can be used. These devices act to increase turbulent mixing through the enhancement of turbulence.
Simulation of gas turbine blade for enhancement of efficiency of gas turbine...IJMER
As day by day population of the world is increasing and our resources are frequently reducing
hence to meet this demand of the world of energy we have to move to a device which have a maximum
efficiency for the condition turbo-machinery are better suited machines having a good efficiency, in
which a Gas turbine is best example of turbo- machinery Turbine is the part of gas turbine which provide
the power to compressor to run or provide power to external source from where energy can be extracted
by attaching alternator in the shaft of Gas turbine. As in earlier a lot of work have been done by the
researcher to increase the efficiency and standard of Gas turbine by the method of film cooling, coating,
and curvature of blade to protect the blade from high temperature of 1200 C° inside the Gas turbine to
increase the life of blade without considering about the efficiency of the engine As in this work is to
enhancement of efficiency of Gas turbine. Gas turbine blade is very important component of engine as
they are attached to both turbine or compressor and turbine provide energy to compressor hence the
turbine blade are more important component to enhance the efficiency which will be analyzed on the
basis of blade height area of fluid flow , area of blade thickness and angles . This simulation is based on
the define value of temperature pressure density of fluid and solid used in blade construction will be
meshed in ANSYS and calculation on the basis of FEM and the result from this calculation over the
temperature and fluid flow inside the gas turbine of different number of blade is studied will be compare
to reach high efficiency point. By determent these value output is formulated on graph chart and will be
studied and result obtain
This document describes mathematical models for simulating the temperature fields of gas turbine blades during convective cooling. It presents boundary integral equation methods (BIEM) and finite difference methods (FDM) for calculating the stationary and quasi-stationary temperature distribution on a blade profile with radial cooling channels. The BIEM approach formulates the problem as a system of boundary integral equations involving temperature values and heat transfer coefficients on the blade surface and cooling channel boundaries. Numerical methods are developed to solve these equations, including discrete logarithmic potential operators and non-uniform surface discretizations. The reliability of the proposed methods is confirmed through computational and experimental analysis of heat transfer for a gas turbine nozzle blade.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Gas turbine cooling system by ahmed shoshan & alaa el-adlAhmed Shoshan
The document summarizes research on gas turbine cooling systems. It examines injection cooling methods, including forward and backward injection. Studies compare the cooling effectiveness of different injection directions and blowing ratios. Backward injection leads to more uniform cooling across the span and higher overall effectiveness compared to forward injection. Conclusions determine that backward injection improves film cooling performance on flat surfaces by promoting stronger interaction between the coolant jet and mainstream flow.
Industrial gas turbine (air cooling & sealing sys) 5thNguyen Phuong Dong
The document discusses the cooling and sealing air systems of industrial gas turbine engines. It describes the purpose of cooling air systems as ensuring parts do not absorb heat from the gas stream and controlling engine temperatures. Cooling air flows around components like the combustor, turbine, and accessories. Turbine blades have intricate internal cooling designs to withstand high temperatures. Sealing air systems use methods like labyrinth seals to prevent oil leakage and control airflows around the turbine disc. The document outlines the components and operation of cooling and sealing air systems, with the goal of demonstrating knowledge of these important gas turbine systems.
Performance optimization of Forced Draft Fan of BBGS Unit # 1Saikat Halder
This document summarizes a project report on the performance optimization of forced draft fans at Budge Budge Generating Station Unit #1 in India. The project was conducted by Saikat Halder, an undergraduate mechanical engineering student, under the guidance of his project supervisor Mr. Samir Bandyopadhyay at the generating station. The report provides background on fans and forced draft fans. It also describes measuring and analyzing the performance of the forced draft fans to identify ways to improve operational efficiency and reduce power consumption.
Rib roughened cooling passages for turbine coolingDevi Archana Das
In modern gas turbine engines, the continuous increase of power for an expected lifetime has resulted in a continuous increase of cycle pressure ratio and turbine inlet temperature. The later implies that advanced materials and cooling techniques must be adapted for a safe operation of the high pressure gas turbine blades and vanes. This need for high power and high efficiency gas turbine engines forces the designer to continuously increase the turbine inlet temperature. In recent military applications, the turbine inlet temperature could be as high as 2000K, far above the melting temperature of the most advanced vane and blade materials. Thus apart from the progress made in the metallurgical domain, a continuous cooling of blade of turbine 1st stages allows operating at temperatures which are far above material’s melting point without affecting component integrity and geometry. The efficiency of the blade cooling system is therefore strictly related to the safe operation of the engine and complete understanding of the convection mechanisms resulting from the cooling techniques is mandatory.
The most common internal heat transfer enhancement methods of heat transfer augmentation in gas turbine airfoils are ribs, pins, jet impingement, and flow disturbing inserts.To maintain the flow inside the cooling passage of turbine blade turbulent all these methods can be used. These devices act to increase turbulent mixing through the enhancement of turbulence.
Simulation of gas turbine blade for enhancement of efficiency of gas turbine...IJMER
As day by day population of the world is increasing and our resources are frequently reducing
hence to meet this demand of the world of energy we have to move to a device which have a maximum
efficiency for the condition turbo-machinery are better suited machines having a good efficiency, in
which a Gas turbine is best example of turbo- machinery Turbine is the part of gas turbine which provide
the power to compressor to run or provide power to external source from where energy can be extracted
by attaching alternator in the shaft of Gas turbine. As in earlier a lot of work have been done by the
researcher to increase the efficiency and standard of Gas turbine by the method of film cooling, coating,
and curvature of blade to protect the blade from high temperature of 1200 C° inside the Gas turbine to
increase the life of blade without considering about the efficiency of the engine As in this work is to
enhancement of efficiency of Gas turbine. Gas turbine blade is very important component of engine as
they are attached to both turbine or compressor and turbine provide energy to compressor hence the
turbine blade are more important component to enhance the efficiency which will be analyzed on the
basis of blade height area of fluid flow , area of blade thickness and angles . This simulation is based on
the define value of temperature pressure density of fluid and solid used in blade construction will be
meshed in ANSYS and calculation on the basis of FEM and the result from this calculation over the
temperature and fluid flow inside the gas turbine of different number of blade is studied will be compare
to reach high efficiency point. By determent these value output is formulated on graph chart and will be
studied and result obtain
This document describes mathematical models for simulating the temperature fields of gas turbine blades during convective cooling. It presents boundary integral equation methods (BIEM) and finite difference methods (FDM) for calculating the stationary and quasi-stationary temperature distribution on a blade profile with radial cooling channels. The BIEM approach formulates the problem as a system of boundary integral equations involving temperature values and heat transfer coefficients on the blade surface and cooling channel boundaries. Numerical methods are developed to solve these equations, including discrete logarithmic potential operators and non-uniform surface discretizations. The reliability of the proposed methods is confirmed through computational and experimental analysis of heat transfer for a gas turbine nozzle blade.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Gas turbine cooling system by ahmed shoshan & alaa el-adlAhmed Shoshan
The document summarizes research on gas turbine cooling systems. It examines injection cooling methods, including forward and backward injection. Studies compare the cooling effectiveness of different injection directions and blowing ratios. Backward injection leads to more uniform cooling across the span and higher overall effectiveness compared to forward injection. Conclusions determine that backward injection improves film cooling performance on flat surfaces by promoting stronger interaction between the coolant jet and mainstream flow.
Industrial gas turbine (air cooling & sealing sys) 5thNguyen Phuong Dong
The document discusses the cooling and sealing air systems of industrial gas turbine engines. It describes the purpose of cooling air systems as ensuring parts do not absorb heat from the gas stream and controlling engine temperatures. Cooling air flows around components like the combustor, turbine, and accessories. Turbine blades have intricate internal cooling designs to withstand high temperatures. Sealing air systems use methods like labyrinth seals to prevent oil leakage and control airflows around the turbine disc. The document outlines the components and operation of cooling and sealing air systems, with the goal of demonstrating knowledge of these important gas turbine systems.
Performance optimization of Forced Draft Fan of BBGS Unit # 1Saikat Halder
This document summarizes a project report on the performance optimization of forced draft fans at Budge Budge Generating Station Unit #1 in India. The project was conducted by Saikat Halder, an undergraduate mechanical engineering student, under the guidance of his project supervisor Mr. Samir Bandyopadhyay at the generating station. The report provides background on fans and forced draft fans. It also describes measuring and analyzing the performance of the forced draft fans to identify ways to improve operational efficiency and reduce power consumption.
Review on Comparative Study between Helical Coil and Straight Tube Heat Excha...IOSR Journals
The purpose of this study is to determine the relative advantage of using a helically coiled heat
exchanger against a straight tube heat exchanger. It is found that the heat transfer in helical circular tubes is
higher as compared to Straight tube due to their shape. Helical coils offer advantageous over straight tubes due
to their compactness and increased heat transfer coefficient. The increased heat transfer coefficients are a
consequence of the curvature of the coil, which induces centrifugal forces to act on the moving fluid, resulting in
the development of secondary flow. The curvature of the coil governs the centrifugal force while the pitch (or
helix angle) influences the torsion to which the fluid is subjected to. The centrifugal force results in the
development of secondary flow. Due to the curvature effect, the fluid streams in the outer side of the pipe moves
faster than the fluid streams in the inner side of the pipe. The difference in velocity sets-in secondary flows,
whose pattern changes with the Dean number of the flow.
In current work the fluid to fluid heat exchange is taken into consideration, Most of the investigations on heat transfer coefficients are for constant wall temperature or constant heat flux. The effectiveness, overall
heat transfer coefficient, effect of coldwater flow rate on effectiveness of heat exchanger when hot water mass
flow rate is kept constant and effect of hot water flow rate on effectiveness when cold water flow rate kept
constant studied and compared for parallel flow, counter flow arrangement of Helical coil and Straight tube
heat exchangers. The inner heat transfer coefficient calculated from Wilson plot method. Then Nusselt no and
correlation obtained on the basis of inner heat transfer coefficient. All readings were taken at steady state
condition of heat exchanger.
The result shows that the heat transfer coefficient is affected by the geometry of the heat exchanger.
Helical coil heat exchanger are superior in all aspect studied here.
The document discusses different methods of cooling turbine blades in gas turbine engines. It describes how turbine blade cooling aims to reduce thermal stresses and temperatures to improve service life and efficiency. The main methods discussed are internal cooling using air passed through internal passages in the blades, and external cooling using film cooling, transpiration cooling or liquid cooling. Internal cooling techniques include convection and impingement, while external cooling uses holes or pores to eject cooling air and form a protective film over the hot blade surfaces. Liquid cooling provides higher heat transfer but requires complex systems to circulate the liquid. Blade cooling allows higher inlet temperatures to turbines, improving efficiency.
There are two main types of gas turbines: axial and radial. Axial turbines are used for large engines and have higher efficiencies but are more expensive to manufacture. Radial turbines are used for small engines and are cheaper and easier to manufacture but have lower efficiencies. Turbine blades can be cooled internally using convection or impingement, or externally using film or effusion cooling to distribute coolant over the blade surface. Sealing systems in gas turbines use different types of seals like labyrinth, ring, hydraulic, carbon, and brush seals to prevent oil leakage and control cooling airflows, with ring seals commonly used except in hot areas and specialized seals to prevent hot gas ingestion into turbine disc cavities.
This document provides information about a shell and tube heat exchanger. It consists of a shell with a bundle of tubes inside it. Process streams flow through the tubes and are heated or cooled by another medium flowing on the outer shell side. Common applications include cooling hydraulic fluid, oil, and other mediums in engines and power systems. The simple design makes shell and tube heat exchangers suitable for a wide variety of industrial heating and cooling applications.
Cooling Tower: Types and performance evaluation, Efficient system operation, Flow control strategies and energy saving opportunities, Assessment of cooling towers
This document provides an overview of axial flow turbines and gas turbine combustors. It discusses how axial flow turbines work by compressing air, combusting fuel to increase temperature, and expanding the gas through the turbine to produce power. It notes advantages of axial turbines like their ability to handle high mass flows and ease of multi-staging. The document also summarizes key design considerations for gas turbine combustors like controlling outlet temperatures, stable combustion over a wide range of conditions, avoiding smoke and emissions, and meeting requirements for aircraft or industrial applications.
Analysis of Coiled-Tube Heat Exchangers to Improve Heat Transfer Rate With Sp...IJMER
Steady heat transfer enhancement has been studied in helically coiled-tube heat exchangers. The outer side of the wall of the heat exchanger contains a helical corrugation which makes a helical rib on the inner side of the tube wall to induce additional swirling motion of fluid particles. Numerical calculations have been carried out to examine different geometrical parameters and the impact of flow and thermal boundary conditions for the heat transfer rate in laminar and transitional flow regimes. Calculated results have been compared to existing empirical formula and experimental tests to investigate the validity of the numerical results in case of common helical tube heat exchanger and additionally results of the numerical computation of corrugated straight tubes for laminar and transition flow have been validated with experimental tests available in the literature. Comparison of the flow and temperature fields in case of common helical tube and the coil with spirally corrugated wall configuration are discussed. Heat exchanger coils with helically corrugated wall configuration show 80–100% increase for the inner side heat transfer rate due to the additionally developed swirling motion while the relative pressure drop is 10–600% larger compared to the common helically coiled heat exchangers. New empirical Co-relation has been proposed for the fully developed inner side heat transfer prediction in case of helically corrugated wall configuration.
This document summarizes the performance evaluation and optimization of forced draft fans for Unit #1 at Budge Budge Generating Station. It finds that the fans' capacity is higher than required and they operate at low power outputs, reducing efficiency. Measurements showed fan flow rates, pressures, and power consumption at different loads. Calculations determined current efficiencies are below design efficiency. Suggestions include design modifications, using variable frequency drives for variable fan speeds, or fluid couplings for improved efficiency.
This document discusses compact heat exchangers, including their types (plate and frame, brazed plate, welded plate, spiral, plate fin, printed-circuit, shell-and-tube), advantages of higher efficiency and lower cost/volume, limitations of fouling and lack of awareness, and design considerations like materials and operating limits. Compact heat exchangers can replace conventional heat exchangers due to their benefits. Security, environmental, and cost aspects are also covered.
What is heat exchanger & its Functions
Types of Heat Exchangers
Compact Heat Exchangers
Part of Fin Plate Heat Exchangers
Advantages & Disadvantages of Fin Plate Exchangers
Materials & Manufacturing
Overall Heat transfer Coefficient & Fouling Factor
LMTD Method
Effectiveness - NTU Method
Industrial fans often play an important role in energy related processes. What about Centrifugal Fans ? They are used quite some processes Rendering, LNG Vaporisers, Food, Fertiliser, Cooling, Ammonia. Like to know more about these hi tech cracks? Have a look.
Types Of Centrifugal Fans Used In Power Plant BoilersNeelRao
The document discusses the different types of centrifugal fans used in power plant boilers. It describes the purpose of boilers in converting water to steam using heat from fuel combustion. It outlines the major types of draft fans - forced draft fans which force air into the system and induced draft fans which draw exhaust gases out. These include backward curved and airfoil centrifugal fans. It also discusses primary air fans which supply air for fuel conveying and flue gas recirculation fans which reduce nitrogen oxide emissions by recirculating exhaust gases back into the combustion chamber. Centrifugal fans of various types are used depending on system requirements.
The document outlines a 14-step process for manually designing a shell and tube heat exchanger using the Kern method. Key steps include: 1) obtaining thermo-physical properties of fluids, 2) performing an energy balance to determine heat duty, 3) assuming an overall heat transfer coefficient, 4) deciding tube passes and calculating the log mean temperature difference, 5) calculating required heat transfer area, 6) selecting tube materials and dimensions, 7) deciding exchanger type and tube pitch, 8) assigning fluids and selecting baffles, 9) calculating heat transfer coefficients, 10) checking the calculated overall heat transfer coefficient, 11) recalculating as needed, 12) calculating overdesign, 13) calculating pressure drops, and 14)
Training manual boiler general arrangement_mongduong iiHOANG VAN DUC
The document provides an introduction and overview of a boiler general arrangement (G/A) drawing for the Mong Duong II Thermal Power Plant project. It includes:
1. A definition of a G/A drawing as showing the arrangement of boiler components, equipment, piping, and ductwork to optimize space and facilitate maintenance.
2. Considerations for developing the G/A drawing including plant specifications, equipment sizes and locations, piping and duct configurations, and structural and access requirements.
3. An introduction to the G/A drawings for this project, including layout diagrams, views, and details showing the arrangement and interfaces of major systems and components.
The document presents information on helical baffle heat exchangers. It begins with introducing heat exchangers and defining a helical baffle heat exchanger. It then discusses the design of helixchangers, including thermal analysis of the helical baffles and tube side as well as hydrodynamic analysis of the shell side. Overall heat transfer coefficient is also examined. Key advantages of helixchangers are reduced bypass effects, fouling, vibration, and maintenance compared to traditional shell and tube exchangers. Future areas of research include CFD optimization and analysis of flow patterns and velocities.
The Presentation describes the basics about the Efficiency and performance of a steam based power plant. It also describes how the heat rate of the power plant is important from the point of view of fuel savings.
This document discusses online efficiency and diagnostics of coal-fired boilers. It provides background on Steag Energy Services and Steag O&M Company. It then covers topics like power plant efficiency calculations, effects of parameters like pressure and temperature on efficiency, sources of losses in the Rankine cycle, challenges like air preheater issues, and potential areas for improvements like cleaning tubes and turbines, condenser maintenance, and installing online performance monitoring software. Finally, it outlines how Steag O&M Company can help with operations, maintenance, commissioning, and benchmarking to reduce generation costs.
Heat transfer equipment is defined by the function it fulfills in a process. On the similar path, Heat exchangers are
the equipment used in industrial processes to recover heat between two process fluids. They are widely used in space
heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, and
natural gas processing. The operating efficiency of these exchangers plays a very key role in the overall running cost
of a plant. So the designers are on a trend of developing heat exchangers which are highly efficient, compact, and cost
effective.
Helically Coiled Tube with Different Geometry and Curvature Ratio on Convecti...AM Publications
A helically coil-tube heat exchanger is generally applied in industry applications due to its compact structure, larger heat transfer area and higher heat transfer capability. Several studies from literature have also indicated that heat transfer rate in helically coiled tube are superior to straight tube due to complex flow pattern exist inside helical pipe. The concept behind compact heat exchanger is to decrease size and increase heat load which is the typical feature of modern helical tube heat exchanger. While the heat transfer characteristics of helical coil heat exchangers are available in the literature, This paper elaborates a brief review on different curvature ratio and geometry of tubes in heat transfer through heat exchangers.
Feedwater heaters are used in thermal power plants to pre-heat feedwater and improve cycle efficiency. They extract steam from various turbine stages and use it to heat incoming feedwater in stages. This reduces the amount of heat needed in the boiler and lowers the condenser pressure, improving efficiency. Feedwater heaters come in low-pressure and high-pressure varieties and utilize extracted steam in shell-and-tube or open heat exchangers. Their performance impacts the overall plant heat rate and emissions. Maintaining optimal temperatures and addressing issues like fouling or leaks is important for efficiency.
The Use of Finite Element Modeling in Thermal Packaging DesignCryopak
The document discusses using finite element modeling in thermal packaging design. It describes the advantages of including thermal modeling in the design process, such as not needing prototypes and being able to test multiple variations. The presentation introduces finite element analysis and heat transfer concepts. It also provides examples of simulating standard designs and using simulation as part of the development process through case studies.
All about Combined Cycle Power Plant, Combustion Chamber and Gas Turbine Blade Cooling. This presentation contains deep knowledge about related topic. I hope this will help you. Best of Luck.
Review on Comparative Study between Helical Coil and Straight Tube Heat Excha...IOSR Journals
The purpose of this study is to determine the relative advantage of using a helically coiled heat
exchanger against a straight tube heat exchanger. It is found that the heat transfer in helical circular tubes is
higher as compared to Straight tube due to their shape. Helical coils offer advantageous over straight tubes due
to their compactness and increased heat transfer coefficient. The increased heat transfer coefficients are a
consequence of the curvature of the coil, which induces centrifugal forces to act on the moving fluid, resulting in
the development of secondary flow. The curvature of the coil governs the centrifugal force while the pitch (or
helix angle) influences the torsion to which the fluid is subjected to. The centrifugal force results in the
development of secondary flow. Due to the curvature effect, the fluid streams in the outer side of the pipe moves
faster than the fluid streams in the inner side of the pipe. The difference in velocity sets-in secondary flows,
whose pattern changes with the Dean number of the flow.
In current work the fluid to fluid heat exchange is taken into consideration, Most of the investigations on heat transfer coefficients are for constant wall temperature or constant heat flux. The effectiveness, overall
heat transfer coefficient, effect of coldwater flow rate on effectiveness of heat exchanger when hot water mass
flow rate is kept constant and effect of hot water flow rate on effectiveness when cold water flow rate kept
constant studied and compared for parallel flow, counter flow arrangement of Helical coil and Straight tube
heat exchangers. The inner heat transfer coefficient calculated from Wilson plot method. Then Nusselt no and
correlation obtained on the basis of inner heat transfer coefficient. All readings were taken at steady state
condition of heat exchanger.
The result shows that the heat transfer coefficient is affected by the geometry of the heat exchanger.
Helical coil heat exchanger are superior in all aspect studied here.
The document discusses different methods of cooling turbine blades in gas turbine engines. It describes how turbine blade cooling aims to reduce thermal stresses and temperatures to improve service life and efficiency. The main methods discussed are internal cooling using air passed through internal passages in the blades, and external cooling using film cooling, transpiration cooling or liquid cooling. Internal cooling techniques include convection and impingement, while external cooling uses holes or pores to eject cooling air and form a protective film over the hot blade surfaces. Liquid cooling provides higher heat transfer but requires complex systems to circulate the liquid. Blade cooling allows higher inlet temperatures to turbines, improving efficiency.
There are two main types of gas turbines: axial and radial. Axial turbines are used for large engines and have higher efficiencies but are more expensive to manufacture. Radial turbines are used for small engines and are cheaper and easier to manufacture but have lower efficiencies. Turbine blades can be cooled internally using convection or impingement, or externally using film or effusion cooling to distribute coolant over the blade surface. Sealing systems in gas turbines use different types of seals like labyrinth, ring, hydraulic, carbon, and brush seals to prevent oil leakage and control cooling airflows, with ring seals commonly used except in hot areas and specialized seals to prevent hot gas ingestion into turbine disc cavities.
This document provides information about a shell and tube heat exchanger. It consists of a shell with a bundle of tubes inside it. Process streams flow through the tubes and are heated or cooled by another medium flowing on the outer shell side. Common applications include cooling hydraulic fluid, oil, and other mediums in engines and power systems. The simple design makes shell and tube heat exchangers suitable for a wide variety of industrial heating and cooling applications.
Cooling Tower: Types and performance evaluation, Efficient system operation, Flow control strategies and energy saving opportunities, Assessment of cooling towers
This document provides an overview of axial flow turbines and gas turbine combustors. It discusses how axial flow turbines work by compressing air, combusting fuel to increase temperature, and expanding the gas through the turbine to produce power. It notes advantages of axial turbines like their ability to handle high mass flows and ease of multi-staging. The document also summarizes key design considerations for gas turbine combustors like controlling outlet temperatures, stable combustion over a wide range of conditions, avoiding smoke and emissions, and meeting requirements for aircraft or industrial applications.
Analysis of Coiled-Tube Heat Exchangers to Improve Heat Transfer Rate With Sp...IJMER
Steady heat transfer enhancement has been studied in helically coiled-tube heat exchangers. The outer side of the wall of the heat exchanger contains a helical corrugation which makes a helical rib on the inner side of the tube wall to induce additional swirling motion of fluid particles. Numerical calculations have been carried out to examine different geometrical parameters and the impact of flow and thermal boundary conditions for the heat transfer rate in laminar and transitional flow regimes. Calculated results have been compared to existing empirical formula and experimental tests to investigate the validity of the numerical results in case of common helical tube heat exchanger and additionally results of the numerical computation of corrugated straight tubes for laminar and transition flow have been validated with experimental tests available in the literature. Comparison of the flow and temperature fields in case of common helical tube and the coil with spirally corrugated wall configuration are discussed. Heat exchanger coils with helically corrugated wall configuration show 80–100% increase for the inner side heat transfer rate due to the additionally developed swirling motion while the relative pressure drop is 10–600% larger compared to the common helically coiled heat exchangers. New empirical Co-relation has been proposed for the fully developed inner side heat transfer prediction in case of helically corrugated wall configuration.
This document summarizes the performance evaluation and optimization of forced draft fans for Unit #1 at Budge Budge Generating Station. It finds that the fans' capacity is higher than required and they operate at low power outputs, reducing efficiency. Measurements showed fan flow rates, pressures, and power consumption at different loads. Calculations determined current efficiencies are below design efficiency. Suggestions include design modifications, using variable frequency drives for variable fan speeds, or fluid couplings for improved efficiency.
This document discusses compact heat exchangers, including their types (plate and frame, brazed plate, welded plate, spiral, plate fin, printed-circuit, shell-and-tube), advantages of higher efficiency and lower cost/volume, limitations of fouling and lack of awareness, and design considerations like materials and operating limits. Compact heat exchangers can replace conventional heat exchangers due to their benefits. Security, environmental, and cost aspects are also covered.
What is heat exchanger & its Functions
Types of Heat Exchangers
Compact Heat Exchangers
Part of Fin Plate Heat Exchangers
Advantages & Disadvantages of Fin Plate Exchangers
Materials & Manufacturing
Overall Heat transfer Coefficient & Fouling Factor
LMTD Method
Effectiveness - NTU Method
Industrial fans often play an important role in energy related processes. What about Centrifugal Fans ? They are used quite some processes Rendering, LNG Vaporisers, Food, Fertiliser, Cooling, Ammonia. Like to know more about these hi tech cracks? Have a look.
Types Of Centrifugal Fans Used In Power Plant BoilersNeelRao
The document discusses the different types of centrifugal fans used in power plant boilers. It describes the purpose of boilers in converting water to steam using heat from fuel combustion. It outlines the major types of draft fans - forced draft fans which force air into the system and induced draft fans which draw exhaust gases out. These include backward curved and airfoil centrifugal fans. It also discusses primary air fans which supply air for fuel conveying and flue gas recirculation fans which reduce nitrogen oxide emissions by recirculating exhaust gases back into the combustion chamber. Centrifugal fans of various types are used depending on system requirements.
The document outlines a 14-step process for manually designing a shell and tube heat exchanger using the Kern method. Key steps include: 1) obtaining thermo-physical properties of fluids, 2) performing an energy balance to determine heat duty, 3) assuming an overall heat transfer coefficient, 4) deciding tube passes and calculating the log mean temperature difference, 5) calculating required heat transfer area, 6) selecting tube materials and dimensions, 7) deciding exchanger type and tube pitch, 8) assigning fluids and selecting baffles, 9) calculating heat transfer coefficients, 10) checking the calculated overall heat transfer coefficient, 11) recalculating as needed, 12) calculating overdesign, 13) calculating pressure drops, and 14)
Training manual boiler general arrangement_mongduong iiHOANG VAN DUC
The document provides an introduction and overview of a boiler general arrangement (G/A) drawing for the Mong Duong II Thermal Power Plant project. It includes:
1. A definition of a G/A drawing as showing the arrangement of boiler components, equipment, piping, and ductwork to optimize space and facilitate maintenance.
2. Considerations for developing the G/A drawing including plant specifications, equipment sizes and locations, piping and duct configurations, and structural and access requirements.
3. An introduction to the G/A drawings for this project, including layout diagrams, views, and details showing the arrangement and interfaces of major systems and components.
The document presents information on helical baffle heat exchangers. It begins with introducing heat exchangers and defining a helical baffle heat exchanger. It then discusses the design of helixchangers, including thermal analysis of the helical baffles and tube side as well as hydrodynamic analysis of the shell side. Overall heat transfer coefficient is also examined. Key advantages of helixchangers are reduced bypass effects, fouling, vibration, and maintenance compared to traditional shell and tube exchangers. Future areas of research include CFD optimization and analysis of flow patterns and velocities.
The Presentation describes the basics about the Efficiency and performance of a steam based power plant. It also describes how the heat rate of the power plant is important from the point of view of fuel savings.
This document discusses online efficiency and diagnostics of coal-fired boilers. It provides background on Steag Energy Services and Steag O&M Company. It then covers topics like power plant efficiency calculations, effects of parameters like pressure and temperature on efficiency, sources of losses in the Rankine cycle, challenges like air preheater issues, and potential areas for improvements like cleaning tubes and turbines, condenser maintenance, and installing online performance monitoring software. Finally, it outlines how Steag O&M Company can help with operations, maintenance, commissioning, and benchmarking to reduce generation costs.
Heat transfer equipment is defined by the function it fulfills in a process. On the similar path, Heat exchangers are
the equipment used in industrial processes to recover heat between two process fluids. They are widely used in space
heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, and
natural gas processing. The operating efficiency of these exchangers plays a very key role in the overall running cost
of a plant. So the designers are on a trend of developing heat exchangers which are highly efficient, compact, and cost
effective.
Helically Coiled Tube with Different Geometry and Curvature Ratio on Convecti...AM Publications
A helically coil-tube heat exchanger is generally applied in industry applications due to its compact structure, larger heat transfer area and higher heat transfer capability. Several studies from literature have also indicated that heat transfer rate in helically coiled tube are superior to straight tube due to complex flow pattern exist inside helical pipe. The concept behind compact heat exchanger is to decrease size and increase heat load which is the typical feature of modern helical tube heat exchanger. While the heat transfer characteristics of helical coil heat exchangers are available in the literature, This paper elaborates a brief review on different curvature ratio and geometry of tubes in heat transfer through heat exchangers.
Feedwater heaters are used in thermal power plants to pre-heat feedwater and improve cycle efficiency. They extract steam from various turbine stages and use it to heat incoming feedwater in stages. This reduces the amount of heat needed in the boiler and lowers the condenser pressure, improving efficiency. Feedwater heaters come in low-pressure and high-pressure varieties and utilize extracted steam in shell-and-tube or open heat exchangers. Their performance impacts the overall plant heat rate and emissions. Maintaining optimal temperatures and addressing issues like fouling or leaks is important for efficiency.
The Use of Finite Element Modeling in Thermal Packaging DesignCryopak
The document discusses using finite element modeling in thermal packaging design. It describes the advantages of including thermal modeling in the design process, such as not needing prototypes and being able to test multiple variations. The presentation introduces finite element analysis and heat transfer concepts. It also provides examples of simulating standard designs and using simulation as part of the development process through case studies.
All about Combined Cycle Power Plant, Combustion Chamber and Gas Turbine Blade Cooling. This presentation contains deep knowledge about related topic. I hope this will help you. Best of Luck.
This is the summary of a study we conducted to simulate heat transfer in one dimension of same and alternating mass systems using statistical mechanics and molecular dynamics.
Thermal analysis of cooling effect on gas turbine bladeeSAT Journals
This document analyzes the film cooling technique used to cool gas turbine blades where temperatures exceed 1122 K. It finds that the thermal efficiency of a cooled gas turbine is slightly lower than an uncooled one due to the decreased turbine inlet temperature from cooling. However, cooling is necessary to increase blade life as temperatures rise above 1123K. The document also examines how increasing the overall pressure ratio further decreases the net power output of cooled gas turbines.
I have worked more than four years on gas turbine performance and how it can be enhanced by "Gas Turbine Inlet Air Cooling". That led to dedicating my BS and MS theses to the topic. Once I presented a summary of gas turbine inlet cooling (principles, methods and issues) when I was a Rotating Equipment Engineer at Monenco Iran Consulting Engineers…
PS Some slides are adapted from the works of "Roozbeh Zomorodian".
Computer Simulation of a Heat Exchanger using AspenAli Raza
A heat exchanger was simulated using Aspen Plus to heat Freon-12 from 240 K to 300 K using ethylene glycol at 350 K. The simulation specified the streams, calculated the heat transfer coefficients, determined the geometry of the exchanger including number of tubes, tube size and length, shell diameter, and baffles. The results of the simulation were examined to check if the design met the objectives of heating the Freon to the required temperature while maintaining a 10 K minimum approach and not exceeding pressure drop limits.
Comparative Study of ECONOMISER Using the CFD Analysis IJMER
This paper presents a simulation of the economizer zone, which allowsstudying the flow
patterns developed in the fluid, while it flows along the length of the economizer. The past failure
details revelsthat erosion is more in U-bend areas of Economizer Unit because of increase in flue gas
velocity near these bends. But it isobserved that the velocity of flue gases surprisingly increases near
the lower bends as compared to upper ones. The model issolved using conventional CFD techniques by
FLUENT software. In which the individual tubes are treated as sub-gridfeatures. A geometrical model
is used to describe the multiplicity of heat-exchanging structures and the interconnectionsamong them.
The Computational Fluid Dynamics (CFD) approach is utilised for the creation of a three-dimensional
modelof the economizer coil of single column tube. With equilibrium assumption applied for
description of the system chemistry. The flue gastemperature, pressure and velocity field of fluid flow
within an economizer tube using the actual bounda
Combined Cycle Gas Turbine Power Plant Part 1Anurak Atthasit
Introduction to Combined Cycle Gas Turbine Power Plant. Describing the advantage and design limit of the CCGT. Overview of Brayton Cycle and Rankine Cycle - showing some basic thermodynamic to explain some background of CCGT.
ABSTRACT
Heat/light/electrical energy is out today’s necessity and has scarcity also. Energy conservation is key requirement of any industry at all times.
In general, industries use heat energy for conservation of raw material to finished product. The source of heat energy is generally saturated or super heated steam. The steam generation is common use one boiler with carity of fuels. Whatever may be the fuel the generation should be as economy as possible which adds to the product cost. Further the usage of steam and recycling steam condensate back to boiler is an art depending on plant layouts.
In this project the steam generator is water tube boiler fired with rice husk. The steam is transferred to the tyre/tube moulds where tyres/tubes are cured while the heat is rejected to the tyres the condensate forms and this condensate is put back to the boiler. While doing so the steam is also stopped back to boiler without rejecting complete heat to the product. This gets flashed into atmosphere at feed water tank. The science of separation of condensate from steam saves energy. Better the separation more the fuel conservation.
In the steam generator the fuel is burnt to heat the water and form steam. This fuel burnt flue gas carries lot of energy, out through chimney. Prior to exhausting through the heat left in flue need to be recovered, through heat recovery mechanisms’. In this project an air-preheater condensate heat recovery unit is the major energy consuming station.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Investigation of mechanical properties on vinylester based bio composite with...eSAT Publishing House
This document describes a study that investigated the mechanical properties of bio-composite materials made of vinylester resin reinforced with dupion silk fibers and filled with varying amounts of gelatin. Bio-composites were prepared with 0%, 10%, 20%, and 30% gelatin content and tested for their tensile, flexural, and hardness properties. The 30% gelatin filled composite achieved a tensile strength of 26.86 MPa, which is comparable to the tensile strength of a human femur bone. The study demonstrates that these bio-composites have potential for use in human bone replacement applications.
Temperature analysis of lna with improved linearity for rf receivereSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Phycoremediation of malachite green and reduction of physico chemical paramet...eSAT Publishing House
1. The document discusses using the algae Chlorella pyrenoidosa to remediate polluted water contaminated with the textile dye malachite green.
2. Experiments were conducted with different concentrations of malachite green and Chlorella pyrenoidosa to determine the optimal levels for decolorization. The dye was completely degraded at a concentration of 15 mg/L with Chlorella.
3. Additional experiments adjusting the pH found that pH 7 was optimal for dye degradation, with Chlorella able to degrade the dye at over 95% efficiency across all concentrations tested.
Deflection control in rcc beams by using mild steel strips (an experimental i...eSAT Publishing House
1) The document discusses an experimental investigation into using mild steel strips as a composite material with traditional reinforced concrete beams to help control deflection.
2) Three types of beams were tested - a control RCC beam, and two beams with mild steel strips embedded vertically along the sides in different configurations to increase stiffness.
3) Preliminary results found that deflection was reduced by about 30% and strength increased by about 25% in the composite beams compared to the control beam.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Background differencing algorithm for moving object detection using system ge...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
A study on glass fiber reinforced polymer clay nanocomposites with sandwich s...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Review of heat transfer augmentation for cooling of turbine blade tip by geom...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
EXPERIMENTAL AND NUMERICAL INVESTIGATION OF ADIABATIC FILM COOLING EFFECTIVEN...IAEME Publication
This study aims at investigating the film cooling effectiveness using both experimentally and numerically for the scaled up gas turbine blade leading edge compound angle model. A compound angle gas turbine blade leading edge model having the five rows of holes, one at stagnation line, two rows of holes at 30 degrees on either side of stagnation line and two rows of holes at 60 degrees on either side of stagnation line. Each row has the five holes at a pitch of 21mm with the varied hole angles of 0, 30, 45, 55 and 60 degrees oriented with the stream line direction.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Experimental Investigation of Finned Tube Heat ExchangerAM Publications
As far today's demand is to manufacture a compact car so there is an urgent need to design an effective
heat exchanger. In this paper the effect of finned heat exchanger over a without finned heat exchanger on overall
heat transfer coefficient is studied. The overall heat transfer coefficient is studied for both heat exchanger with air
velocity 3m/s, 4m/s, 5m/s and 6m/s and coolant flow 180 Lit/hr, 260 Lit/hr , 340 Lit/hr, 420 Lit/hr ad 500 Lit/hr.
Finned-tube heat exchangers are common and vital components in many energy systems Fin-and-tube heat
exchangers are widely used in several domains such as heating, ventilating, refrigeration and air conditioning systems
The fin performance is commonly expressed in terms of heat transfer coefficient and fin effectiveness, which is
defined as the ratio of the heat transfer rate with fin to the heat transfer rate in without fin heat exchanger. This case
is the one providing the maximum heat transfer rate because this corresponds to the maximum driving potential
(temperature difference) for convection heat transfer. The research work summarized in this presents a combined
analytical, experimental and numerical investigation of Overall heat transfer coefficient of coolant as water by use of
circular finned tube heat exchanger and without fin tube exchanger with force convection. The heat transfer and
pressure drop results for the pin fin heat exchanger were compared with the results for a smooth-pipe heat exchanger.
The experimental system is quite similar to cars' cooling system. The compares the heat transfer coefficient, pressure
drop, overall heat transfer coefficient with the finned tube heat exchanger and without finned tube heat exchanger.
From the experiment Finned-tube heat exchanger gives the overall heat transfer coefficient 14.07W/m2K.
Analysis of Double Pipe Heat Exchanger With Helical FinsIRJET Journal
This document analyzes a double pipe heat exchanger with helical fins through computational fluid dynamics (CFD). It aims to study the flow and temperature fields inside the tubes for different helical fin angles. The geometry of the double pipe heat exchanger is modeled in CATIA V5 and meshed in Hypermesh. CFD simulations are performed in ANSYS Fluent to analyze the flow and temperature distributions for fin angles of 0, 5, 10, 15, 20, and 25 degrees. The results determine that heat transfer rate and overall heat transfer coefficient increase with helical fins compared to a smooth tube, with fins providing additional surface area to enhance heat transfer.
IRJET- Design and Computational Analysis of Shell and Tube Heat Exchanger Con...IRJET Journal
This document describes a computational fluid dynamics (CFD) analysis of a shell and tube heat exchanger considering various parameters. The analysis models and simulates the geometry of a shell and tube heat exchanger using ANSYS to study the temperature and pressure fields inside the shell. Variables analyzed include mass flow rate, baffle inclination angle, outlet temperature, and pressure drop. The results show increased heat exchanger performance with a helical baffle design compared to a conventional segmental baffle design.
Experimental investigation of double pipe heat exchanger with helical fins on...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IRJET- Experimental Analysis of Circular Perforated Fin Arrays by Forced Conv...IRJET Journal
This document summarizes an experimental analysis of heat transfer from circular perforated fin arrays under forced convection using a wind tunnel. Trapezoidal microfin arrays with circular perforations were selected and designed using Taguchi Method. Experiments were conducted in a wind tunnel on three test specimens - a solid rectangular fin array and two trapezoidal perforated fin arrays with different perforation pitches. The perforated fin arrays showed higher overall efficiency and effectiveness compared to the solid fin array. Maximum overall efficiency was obtained for the array with 5mm perforation pitch at an air velocity of 2m/s and heat input of 150W. Optimum effectiveness was obtained for the array with 7mm pitch at 2m/s and 120W input
The document describes a computational fluid dynamics (CFD) analysis of heat transfer in a rectangular channel with blockages containing elongated holes. A model of the channel was created in design software and meshed before performing CFD simulations. The simulations analyzed how heat transfer coefficients and Nusselt numbers varied with the pitch ratio of the blockages for different Reynolds numbers. Results showed that heat transfer initially increased with pitch ratio up to a value of 6.0, then decreased with further increases, due to changes in flow reattachment. Blockages with shorter holes enhanced heat transfer more but also increased pressure drops more compared to longer holes. The CFD results were also validated against available experimental data, with good agreement.
Natural convection heat transfer flow visualization of perforated fin arrays ...eSAT Journals
Abstract
The present paper reports, the validation of results of modeling and simulation in CFD by experiment on the fluid flow and heat
transfer characteristics of a fin arrays with lateral circular perforation and its external dimensionally equivalent solid fin arrays
equipped on horizontal flat surface a problem of natural convection. The simulation is carried out using the fluid flow (CFX)
workbench of ANSYS 12.0. In this study, results shows that formation of the stagnant layer around the solid fin array which slowdowns
the heat dissipation rate. Increase in the fluid flow movement around the fin results increase in the heat dissipation rate. It can
be achieved by adding perforation to the fins. Natural convection is a buoyancy driven phenomenon; the state of the art of CFX was
used to carry the study of fluid flow separation and velocity field over a fin array. New designed perforated fins have an improvement
in average Nusselt number, over its external dimensionally equivalent solid fin arrays.
Keywords: CFD simulation, perforated fins, Natural convection, Heat sink, Nusselt number, Flow Visualization
IRJET- Modelling and CFD Simulation of Prototype of AC Plant Chiller On-Board...IRJET Journal
This document summarizes a study that models and simulates a shell and tube heat exchanger used in marine ship air conditioning plants. The study involves:
1. Modeling the geometry of a prototype shell and tube heat exchanger in Solidworks based on design calculations.
2. Meshing the model in ICEM CFD and applying boundary conditions representing different mass flow rates to simulate heat transfer.
3. Using ANSYS Fluent CFD software to analyze temperature distribution and flow patterns within the shell and tubes at 100% and 75% loading.
4. Comparing CFD results to experimental temperature data from factory acceptance trials to validate the simulation model.
The goal is to model the
Design and Analysis of Heat Exchanger for Maximum Heat Transfer Rate (Multi M...IRJET Journal
This document summarizes a study on optimizing the design of a shell and tube heat exchanger to maximize heat transfer rate. The researchers designed a shell and tube heat exchanger using standard TEMA specifications. They then analyzed different tube designs, baffle inclinations, and coolant fluids using computational fluid dynamics simulations. The optimum design was found to be a tube with both angled and stepped sections, baffles inclined at 35 degrees, and a coolant of copper oxide nanoparticles in water. This design achieved a temperature drop of 48.6 degrees Celsius between the hot and cold fluids.
Experimental Investigation of Heat Transfer through Rectangular and Trapezoid...IRJET Journal
The document describes an experimental investigation of heat transfer through rectangular and trapezoidal fins made of aluminum 6063 alloy. Rectangular and trapezoidal fins were fabricated from the alloy and experiments were conducted under steady state conditions. Local temperature, heat flux, heat transfer coefficients, and Reynolds numbers were estimated. The findings showed that forced convection was more effective than free convection, and the trapezoidal fin enhanced heat transfer by up to 48% compared to the rectangular fin under different heat supply conditions. The document provides details on the experimental setup, material properties of the aluminum 6063 alloy, and methodology for collecting temperature readings along the fins.
PERFORMANCE ENHANCEMENT OF HEAT EXCHANGERS USING VORTEX FLAPSIRJET Journal
The document discusses performance enhancement of heat exchangers using vortex flaps. It proposes designing a heat exchanger with twisted internal flaps to produce counter-rotating vortices inside the tube, increasing turbulence and convection of colder fluid. This is meant to improve heat transfer rate. Previous studies on using inserts like twisted tapes, coiled wires, and conical rings to enhance heat transfer in tubes are summarized. Numerical simulations will be conducted to analyze heat transfer and pressure drop characteristics of the designed heat exchanger.
Computational Analysis of Thermal Behavior within a Scraped Surface Heat Exch...ijtsrd
The document discusses a computational analysis of thermal behavior within a scraped surface heat exchanger (SSHE). SSHEs are used to prevent solids deposition on heat transfer surfaces in industries like pharmaceutical and food processing. The study models the 3D geometry of an SSHE using two designs with 2 blades and 3 blades. Glycerin flow is analyzed using computational fluid dynamics. Results show that reducing the number of rotating blades to 2 improves heat transfer by decreasing bulk fluid temperature and increasing the local heat transfer coefficient, especially at higher rotational velocities. The analysis provides insights that can aid in SSHE design for applications involving viscous fluids.
Transient Thermal Analysis for Heat Dissipation from Engine Cylinder Block wi...ijtsrd
The cost of fuel and materials in all sectors is rising day by day. In the IC engine, the engine fails primarily because the heat transfer from the cylinder wall to the ambient air is inadequate. Heat is derived from the cylinder wall in the engine by means of convection heat transfer through the fins. In this study, a 3 dimensional numerical 3 D transient thermal state simulation was used to investigate the heat dissipation of the engine cylinder fin with holes of different shapes hexagonal and an elliptical . ANSYS 17.0 simulation software was used to research the physiognomy of the heat transfer physiognomies of an engine cylinder fin with and without hole. The results indicate that, the fin with an elliptic hole attain a temperature of 797.94 °C at 14 seconds in comparison to other where with hexagonal hole 798.02 °C, and without hole 798.14°C. So above values clearly shows that fin with an elliptic hole dissipates more heat as compare to fin with hexagonal hole or without hole. Fin with an elliptic hole have a total heat flux of 56122 W m² comparison to other where with hexagonal hole 49967 W m², and without hole 46704 W m². From the above results it is clearly shows that, the new proposed shape fin or fin configuration will greatly improve the heat transfer rate and increase the fin efficiency. Optimum results are obtained when we provide an elliptic hole in an engine cylinder fin Sunil Kumar Bharti | Prof. Rohit Soni "Transient Thermal Analysis for Heat Dissipation from Engine Cylinder Block with Different Shaped Holes in Fins using CFD" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-6 , October 2020, URL: https://www.ijtsrd.com/papers/ijtsrd35736.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/35736/transient-thermal-analysis-for-heat-dissipation-from-engine-cylinder-block-with-different-shaped-holes-in-fins-using-cfd/sunil-kumar-bharti
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
This document discusses a computational fluid dynamics (CFD) analysis of a shell and tube heat exchanger with different baffle inclinations. The study aims to determine the optimal baffle inclination angle and mass flow rate. It analyzes heat transfer characteristics for baffle inclinations of 0, 10 and 20 degrees. The results indicate that a helical baffle configuration forces fluid rotation, increasing heat transfer rates and coefficients more than a segmental baffle design. Overall, the CFD simulation allows determination of outlet temperatures, pressure drops, and optimal design parameters for improved heat exchanger performance.
Experimentation on heat pipe and cfd analysis for performance enhancementeSAT Journals
Abstract
Heat Pipe is a heat transfer device used in many applications and it is very similar in some respects to the thermosyphon. Since there were several limitations of thermosyphon, heat pipe was developed. The idea of the heat pipe was first suggested in 1942, since then over a several decades the serious development of a heat pipe took place. Heat pipe mainly consists of three regions viz. evaporator, adiabatic and condenser section. The heat pipe differs from the thermosyphon by virtue of its ability to transport heat against gravity by an evaporation-condensation cycle. This research work includes experimentation on available heat pipe, development of CFD model and its validation with experimental results using CFD Tool. The results obtained by CFD are in good agreement with an experimental results. Since the heat pipe is used for transferring the heat, this research work focuses on increasing the heat transfer by modified model, modifications in terms of increased surface area, is proposed. From CFD analysis it was found that the proposed modified heat pipe shows enhancement in performance in terms of heat transfer rate by 19% when it is simulated for without heat sink case and 45% while with heat sink case, compared to conventional heat pipe. The mixture multiphase model from CFD too is used for simulation of heat pipe.
Similar to Numerical simulation of gas turbine blade cooling for enhancement of heat transfer of the blade tip (20)
Hudhud cyclone caused extensive damage in Visakhapatnam, India in October 2014, especially to tree cover. This will likely impact the local environment in several ways: increased air pollution as trees absorb less; higher temperatures without tree canopy; increased erosion and landslides. It also created large amounts of waste from destroyed trees. Proper management of solid waste is needed to prevent disease spread. Suggested measures include restoring damaged plants, building fountains to reduce heat, mandating light-colored buildings, improving waste management, and educating public on health risks. Overall, changes are needed to water, land, and waste practices to rebuild the environment after the cyclone removed green cover.
Impact of flood disaster in a drought prone area – case study of alampur vill...eSAT Publishing House
1) In September-October 2009, unprecedented heavy rainfall and dam releases caused widespread flooding in Alampur village in Mahabub Nagar district, a historically drought-prone area.
2) The flood damaged or destroyed homes, buildings, infrastructure, crops, and documents. It displaced many residents and cut off the village.
3) The socioeconomic conditions and mud-based construction of homes in the village exacerbated the flood's impacts, making damage more severe and recovery more difficult.
The document summarizes the Hudhud cyclone that struck Visakhapatnam, India in October 2014. It describes the cyclone's formation, rapid intensification to winds of 175 km/h, and landfall near Visakhapatnam. The cyclone caused extensive damage estimated at over $1 billion and at least 109 deaths in India and Nepal. Infrastructure like buildings, bridges, and power lines were destroyed. Crops and fishing boats were also damaged. The document then discusses coping strategies and improvements needed to disaster management plans to better prepare for future cyclones.
Groundwater investigation using geophysical methods a case study of pydibhim...eSAT Publishing House
This document summarizes the results of a geophysical investigation using vertical electrical sounding (VES) methods at 13 locations around an industrial area in India. The VES data was interpreted to generate geo-electric sections and pseudo-sections showing subsurface resistivity variations. Three main layers were typically identified - a high resistivity topsoil, a weathered middle layer, and a basement rock. Pseudo-sections revealed relatively more weathered areas in the northwest and southwest. Resistivity sections helped identify zones of possible high groundwater potential based on low resistivity anomalies sandwiched between more resistive layers. The study concluded the electrical resistivity method was useful for understanding subsurface geology and identifying areas prospective for groundwater exploration.
Flood related disasters concerned to urban flooding in bangalore, indiaeSAT Publishing House
1. The document discusses urban flooding in Bangalore, India. It describes how factors like heavy rainfall, population growth, and improper land use have contributed to increased flooding in the city.
2. Flooding events in 2013 are analyzed in detail. A November rainfall caused runoff six times higher than the drainage capacity, inundating low-lying residential areas.
3. Impacts of urban flooding include disrupted daily life, damaged infrastructure, and decreased economic activity in affected areas. The document calls for improved flood management strategies to better mitigate urban flooding risks in Bangalore.
Enhancing post disaster recovery by optimal infrastructure capacity buildingeSAT Publishing House
This document discusses enhancing post-disaster recovery through optimal infrastructure capacity building. It presents a model to minimize the cost of meeting demand using auxiliary capacities when disaster damages infrastructure. The model uses genetic algorithms to select optimal capacity combinations. The document reviews how infrastructure provides vital services supporting recovery activities and discusses classifying infrastructure into six types. When disaster reduces infrastructure services, a gap forms between community demands and available support, hindering recovery. The proposed research aims to identify this gap and optimize capacity selection to fill it cost-effectively.
Effect of lintel and lintel band on the global performance of reinforced conc...eSAT Publishing House
This document analyzes the effect of lintels and lintel bands on the seismic performance of reinforced concrete masonry infilled frames through non-linear static pushover analysis. Four frame models are considered: a frame with a full masonry infill wall; a frame with a central opening but no lintel/band; a frame with a lintel above the opening; and a frame with a lintel band above the opening. The results show that the full infill wall model has 27% higher stiffness and 32% higher strength than the model with just an opening. Models with lintels or lintel bands have slightly higher strength and stiffness than the model with just an opening. The document concludes lintels and lintel
Wind damage to trees in the gitam university campus at visakhapatnam by cyclo...eSAT Publishing House
1) A cyclone with wind speeds of 175-200 kph caused massive damage to the green cover of Gitam University campus in Visakhapatnam, India. Thousands of trees were uprooted or damaged.
2) A study assessed different types of damage to trees from the cyclone, including defoliation, salt spray damage, damage to stems/branches, and uprooting. Certain tree species were more vulnerable than others.
3) The results of the study can help in selecting more wind-resistant tree species for future planting and reducing damage from future storms.
Wind damage to buildings, infrastrucuture and landscape elements along the be...eSAT Publishing House
1) A visual study was conducted to assess wind damage from Cyclone Hudhud along the 27km Visakha-Bheemli Beach road in Visakhapatnam, India.
2) Residential and commercial buildings suffered extensive roof damage, while glass facades on hotels and restaurants were shattered. Infrastructure like electricity poles and bus shelters were destroyed.
3) Landscape elements faced damage, including collapsed trees that damaged pavements, and debris in parks. The cyclone wiped out over half the city's green cover and caused beach erosion around protected areas.
1) The document reviews factors that influence the shear strength of reinforced concrete deep beams, including compressive strength of concrete, percentage of tension reinforcement, vertical and horizontal web reinforcement, aggregate interlock, shear span-to-depth ratio, loading distribution, side cover, and beam depth.
2) It finds that compressive strength of concrete, tension reinforcement percentage, and web reinforcement all increase shear strength, while shear strength decreases as shear span-to-depth ratio increases.
3) The distribution and amount of vertical and horizontal web reinforcement also affects shear strength, but closely spaced stirrups do not necessarily enhance capacity or performance.
Role of voluntary teams of professional engineers in dissater management – ex...eSAT Publishing House
1) A team of 17 professional engineers from various disciplines called the "Griha Seva" team volunteered after the 2001 Gujarat earthquake to provide technical assistance.
2) The team conducted site visits, assessments, testing and recommended retrofitting strategies for damaged structures in Bhuj and Ahmedabad. They were able to fully assess and retrofit 20 buildings in Ahmedabad.
3) Factors observed that exacerbated the earthquake's impacts included unplanned construction, non-engineered buildings, improper prior retrofitting, and defective materials and workmanship. The professional engineers' technical expertise was crucial for effective post-disaster management.
This document discusses risk analysis and environmental hazard management. It begins by defining risk, hazard, and toxicity. It then outlines the steps involved in hazard identification, including HAZID, HAZOP, and HAZAN. The document presents a case study of a hypothetical gas collecting station, identifying potential accidents and hazards. It discusses quantitative and qualitative approaches to risk analysis, including calculating a fire and explosion index. The document concludes by discussing hazard management strategies like preventative measures, control measures, fire protection, relief operations, and the importance of training personnel on safety.
Review study on performance of seismically tested repaired shear wallseSAT Publishing House
This document summarizes research on the performance of reinforced concrete shear walls that have been repaired after damage. It begins with an introduction to shear walls and their failure modes. The literature review then discusses the behavior of original shear walls as well as different repair techniques tested by other researchers, including conventional repair with new concrete, jacketing with steel plates or concrete, and use of fiber reinforced polymers. The document focuses on evaluating the strength retention of shear walls after being repaired with various methods.
Monitoring and assessment of air quality with reference to dust particles (pm...eSAT Publishing House
This document summarizes a study on monitoring and assessing air quality with respect to dust particles (PM10 and PM2.5) in the urban environment of Visakhapatnam, India. Sampling was conducted in residential, commercial, and industrial areas from October 2013 to August 2014. The average PM2.5 and PM10 concentrations were within limits in residential areas but moderate to high in commercial and industrial areas. Exceedance factor levels indicated moderate pollution for residential areas and moderate to high pollution for commercial and industrial areas. There is a need for management measures like improved public transport and green spaces to combat particulate air pollution in the study areas.
Low cost wireless sensor networks and smartphone applications for disaster ma...eSAT Publishing House
This document describes a low-cost wireless sensor network and smartphone application system for disaster management. The system uses an Arduino-based wireless sensor network comprising nodes with various sensors to monitor the environment. The sensor data is transmitted to a central gateway and then to the cloud for analysis. A smartphone app connected to the cloud can detect disasters from the sensor data and send real-time alerts to users to help with early evacuation. The system aims to provide low-cost localized disaster detection and warnings to improve safety.
Coastal zones – seismic vulnerability an analysis from east coast of indiaeSAT Publishing House
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Numerical simulation of gas turbine blade cooling for enhancement of heat transfer of the blade tip
1. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 09 | Sep-2014, Available @ http://www.ijret.org 35
NUMERICAL SIMULATION OF GAS TURBINE BLADE COOLING FOR ENHANCEMENT OF HEAT TRANSFER OF THE BLADE TIP Sushil Sunil Gaikwad1, C. R. Sonawane2 1PG Student, Mechanical Engg Dept, Pimpri Chinchwad College of Engg, Pune, Maharashtra, India 2Asso. Prof, Mechanical Engg Dept, Pimpri Chinchwad College of Engg, Pune, Maharashtra, India Abstract In today’s industrial scenario, Gas Turbine is one of the most important components of auxiliary power plant system. In order maximize the overall performance and efficiency of all modern turbines, which theoretically operate according to Brayton cycle, they are operated at a very high temperature. These temperatures are so high that, which may fall in the region of turbine blade material melting point temperatures. Due to such high temperatures there is a possibility that the turbine blades may get damaged due to produced thermal stresses and presents a possible threat to the turbine system as well as the operators. Hence to ensure safe and reliable working of the turbines an effective and reliable cooling system is necessary. Currently available methods for cooling of the turbine blades include film cooling with impingement cooling for the leading edge, rib turbulated cooling using serpentine passages for the middle portion of the blade and pin fin cooling for the trailing edge of the turbine blades. The cooling mechanism for turbine blades must include cooling for all possible regions which are exposed to hot gas flow. The turbine blade tip is one of the critical regions which are severely exposed to hot gas flow occurring due to the leakage of gases from the clearance gap between the turbine tip and the shroud. Hence the tip of the turbine blade must be cooled effectively to prevent thermal expansion of the turbine blade tip due to heating. This cooling will eventually help to avoid rubbing of blades to the shroud which may cause their wear. In this paper the effect of provision of pins of two different diameters and heights over the turbine blade tip at the corners, on the heat transfer has been investigated. The results obtained were compared with the heat transfer of smooth tip two pass channels. Investigations were carried out at different Reynolds numbers ranging from 200000 to 450000. It was found that if pins are provided at the corners the local heating of the tip at corners is avoided. A heat transfer augmentation of about 1.3 times was observed as compared to a smooth surface with pressure drop of less than 6 %. Hence the proper arrangement and number of pin fins is recommended for augmentation of heat transfer over the turbine blade tip. Keywords - Turbine Tip Cooling, Turbulence, numerical simulation, hotspots.
-------------------------------------------------------------------***-------------------------------------------------------------------
1. INTRODUCTION
Modern gas turbines operate at very high temperatures for increasing the efficiency and performance of the turbines. But these high temperatures may exceed the material melting temperature of the turbine blades. Hence proper cooling system must be employed for the cooling of the turbine blades for their long life. The leading edge of the turbine blade airfoil is cooled by using impingement cooling with film cooling, the middle portion is cooled by using rib turbulated cooling and the trailing edge is cooled by using pin fin cooling with ejection. The cooling of the turbine blades must include all the regions exposed to hot gases. One of such regions of a blade in case of high pressure turbines is the tip of the blade. For the mechanical and thermal expansion of the blades a clearance gap is provided between the turbine blade tip and the shroud/ fixed casing of the turbine. But due to this clearance gap, leakage of hot gases occurs mainly due to the difference between the pressure side and suction side of the blade. And this gap cannot be completely eliminated since it will cause rubbing of the blades to the casing thereby causing damage to the turbine. Hence the cooling of the turbine blade tip must be given a special attention for safe and efficient working of the turbines. One very common method of cooling is by providing serpentine passages in the middle portion of the turbine blade. Fig 2 shows the typical serpentine passages that are commonly used for the internal cooling of turbine blades.
Fig 1 Typical cooling techniques of turbine blade
2. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 09 | Sep-2014, Available @ http://www.ijret.org 36
There are several publications available discussing the
effects of providing ribs/vanes/pin fins inside these
serpentine passages which improve the heat transfer by
considerable amount. A slight modification in the method of
tip cooling involves direct geometrical modifications to the
internal tip of the turbine blades. Ron S. Bunker [1]
experimentally investigated the effect of providing pin
arrays to the internal tip cap of turbine blades. Five different
configurations were used to compare the heat transfer
coefficients. A smooth surface, two different heights of
aluminium pin arrays, one more closely spaced array and
one pin array made of insulating material were
experimentally tested. As compared to smooth tip it was
found that the provision of pin arrays showed heat transfer
coefficient improved by a factor of 2.1. Also this method
resulted in negligible pressure drop as compared to that of a
smooth surface of the turbine internal tip. Gongnan Xie and
Bengt Sunden [2] simulated the same geometry as given by
Bunker. Only here the difference was provision of
hemispherical dimples/concave dimples on the internal tip
cap instead of arrays in case of Bunker’s experiment. Here
the flow was numerically simulated and studied by using
two different heights of dimples were used. It was found that
the heat transfer was doubled compared to smooth tip by
provision of dimples on the surface of internal tip cap of the
turbine blades. In yet another analysis Gongnan Xie [3]
carried out numerical simulations for six different
arrangements of the guide rib/vanes in a two pass serpentine
passage.
Fig 2 A typical two pass serpentine passages inside a turbine
blade [2]
The guide ribs/vanes were placed at different locations
inside the passage and their effect on the heat transfer
coefficient was examined numerically using computational
fluid dynamics technique. It was concluded that the tip heat
transfer coefficients of channels with guide ribs/vanes are
upto 65% higher than those of a channel without the
provision of guide ribs/vanes. Another conclusion made was
that there would be improved heat transfer if the guide
ribs/vanes are properly placed inside the channel. But this
method was found o be less effective as compared to the
direct geometrical modifications as proposed by Bunker.
Another option of tip cooling was proposed by Gongnan Xie
and Bengt Sunden [4] which stated the use of pin fins for the
cooling of tip of the turbine blades. Also noteworthy was the
point that the heat transfer enhancement for the pin fins is
higher than that for the pin arrays once these pin fins are
properly placed on the tip of the blade. A very limited data is
available and few researches have been conducted on the
cooling of turbine blades by direct geometrical
modifications to the internal tip cap. All the publications
explaining this method have considered smooth channels
without ribs i.e. assuming that the channels have constant
heat transfer surfaces. Hence the heat transfer enhancement
for turbine tip has been studied by considering smooth
channels instead of ribbed ones.
2. GEOMETRY OF PHYSICAL MODEL
The physical model considered for this study is as shown in
the Fig 3. It consists of a two pass rectangular channel with
inlet and outlet sections having a cross sectional area of 6.99
x 13.97 sq.cm. The hydraulic diameter from the geometry is
calculated as 9.32 cm. A gap of 8.89 cm is assumed from
the tip surface to the turn surface i.e. between the divider
and the tip wall. The thickness of the internal separation tip
is 2.54 cm. the height of the two pass channel is 13.97 cm.
Rest of the features of the geometry are similar to those of
Bunker [1] for a smooth tip two pass channel. But the
geometry varies at the tip surface when the case of pins is
considered
Fig 3 Experimental model [1]
Fig 4 Simulated model
3. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 09 | Sep-2014, Available @ http://www.ijret.org 37
3. DESCRIPTION OF COMPUTATIONAL
MODEL
3.1 Summary of Model
The numerical model considered in this study is a two pass
serpentine channel with sharp 180° turn. A schematic
diagram of the geometrical models used in this study is
shown in Fig. 4. The two-pass channels have rectangular
cross-section with an aspect ratio of 1:2 (the flow spanwise
width in the y-direction, is the half of the channel height in
the z-direction), where the shorter walls are the turbine
pressure side and suction side. Each channel is 139.7 and
69.9 mm with a hydraulic diameter of 93.13 mm. The
lengths of the inlet channel (first-pass) and the outlet
channel (second-pass) are about ten hydraulic diameters, and
both the inlet and outlet channels are smooth without any
turbulators. The internal separation rib (divider) is assumed
to be 25.4 mm thick so that the full tip-wall cap section is
139.7 by 165.1 mm. A distance of 88.9 mm is used for the
flow gap between the divider and the tip-wall. The smooth-tip
two-pass channel is used as a baseline for performance
comparison with the protruded-tip two-pass channels. Other
numerical details are similar to those of Bunker’s
geometrical model. The surfaces studied for the internal tip
are also similar to those studied by Bunker [1].
3.2 Computational Details
To investigate the temperature distributions and the heat
transfer augmentation in the three dimensional flow field, a
k-ε turbulence modeling was selected. The pressure and
velocity were linked by Semi Implicit Method for Pressure
Linked Equation (SIMPLE) scheme. The finite modeling
was conducted in Ansys Fluent 14.0. The Fluent code uses
finite volume method to solve the governing equations of the
flow. Mesh generation was done in Ansys Mesh Modeler.
This study examined turbulent flow and the heat transfer
characteristics for a smooth tipped surface and the protruded
surface were also checked for enhancement in heat transfer
3.3 Selection of Turbulence Model
A realizable k-ε turbulence model was selected based on the
previous studies. The realizable k-ε model is very effective
in case of flows which involve sudden turns involving sharp
streamline curvatures. As the flow involves a 180° sharp
turn it is recommended to use this turbulence model for the
current simulation. The flow features like separation,
recirculation and impingement are quite accurately resolved
by this turbulence model.
3.4 Governing Equations
The governing equations for the flow are as expressed below
Continuity equation [2]
.V 0
Dt
D
Momentum equation
X-momentum
x
xx yx zx f
x x y z
p
Dt
Du
Y-momentum
y
xy yy zy f
y x y z
p
Dt
Dv
Z-momentum
z
xz yz zz f
y x y z
p
Dt
Dw
Energy Equation for fluid [2]
) )
Pr Pr
((
i
t
i i
i
x
T
x x
u T
3.5 Boundary Conditions
Although the heat transfer on the leading and trailing walls
are important for gas turbine blade design, the heat transfer
enhancement of a protruded tip-wall over that of a smooth
tip-wall is the major concern of this paper. Therefore, except
for the external smooth tip-wall, the remaining walls are
assumed to be adiabatic. A constant heat flux is prescribed
on the bottom wall. No-slip velocity conditions are applied
at all walls. A uniform velocity (different for different Re)
and temperature are set at the inlet and an outflow condition
is chosen at the outlet. A turbulence intensity level of 10 %
and the hydraulic diameter are used to compute the
turbulence quantities at the inlet. Due to the conjugation of
fluid and solid heat transfer, the boundary conditions for the
interfaces between the dimple surfaces and the internal
dimpled tip-cap surface are automatically coupled. The fluid
is assumed to be incompressible with constant thermal
physical properties and the flow is assumed to be three
dimensional, turbulent, steady and non-rotating. The
working fluid is dry air. In this study, because of high
Reynolds numbers and the complicated computational
model, the standard wall functions of the k-ε model 2
equation models are applied on the walls for the near wall
treatment. The convergence criterion for continuity,
momentum, k and e equations is 10^4but 10^7 for the
energy equation.
3.6 Grid Dependence Study
A grid dependence test is carried out in order to select the
appropriate mesh before simulating the flow. The details of
the mesh independence will be included in a separate study
paper. For the grid independence test four different grid
were chosen- 18410 cells, 54321 cells, 91152 cells and
115842 cells studied. Various parameters like temperature,
4. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 03 Issue: 09 | Sep-2014, Available @ http://www.ijret.org 38
pressure and eddy viscosity were evaluated over these grids.
It was found that the grids with 91152 cells and 115842 cells
showed the closest results amongst the four. Hence in order
to avoid the computational time and also to reduce
computational resources the grid with 91152 cells was
selected for further simulations.
3. RESULTS AND DISCUSSIONS
3.1 Definition of Parameters
Before explaining the results the following parameters are
defined
The local Nusselts number is given by
The overall Nusselts number is given by
k
hD
Nu h
3.2 Validation of Model
Before finalizing the simulation and processing further
calculations we need to validate the results
It is seen from Fig 5 and Fig 6 that the values of the
numerical results are in accordance with the experimental
results of Bunker [1] with a maximum deviation less than 15
%. The results have been simulated using the realizable k-ε
turbulence model with a standard wall function. A good
agreement between the experimental results and the current
computational model has been achieved. This validates our
numerical simulations.
Fig. 5 Nusselts number for current study and Bunker’s [1]
experimental results for a smooth tip two pass channel
Fig. 6 Pressure drop for current study and Bunker’s [1]
experimental results for a smooth tip two pass channel
After the model validation the results have been computed
for different configurations of the tip i.e. by modifying the
surface of the tip with arrangement of pins at different
locations and with different dimensions as explained further.
Also the mass flow rates from numerical and calculated
results have been compared. Both the results give almost the
same values indicating the simulated model is valid. The
values are a listed in the Table 1.
Table 1
Param
eter
Study Re=20
0000
Re=30
0000
Re=35
0000
Re=45
0000
Mass
Flow
Rate(
kg/s)
Nume
rical
0.3601 0.5624 0.6302 0.8102
Calcul
ated
0.3748 0.5624 0.6562 0.8434
%
deviat
ion
3.99 nil
3.99 3.99
In order to understand the flow patterns and the temperature
regions the temperature contours over the tip surface have
been plotted. Fig 7 shows the temperature contours for a
smooth surface at a Reynolds number Re=200000. From the
temperature contours it is seen that the corners of the tip are
the portions which are more vulnerable to high temperatures.
Fig. 7 Temperature contour for smooth channel at
Re=200000
0
200
400
600
800
1000
Nu
Re
This
study
Bunker
[1]
0
1000
2000
3000
4000
5000
6000
200000
300000
350000
450000
Δp (pressure drop)
Re (Reynolds number)
This
study
Bunker
[1]
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4. OVERALL COMPARISONS
Two types of surfaces were compared. The configuration of the two surfaces were same only the heights of the pins used at the corners were different, more height in the latter case. The configuration is as shown in the fig.8.
(a) (b) Fig. 8 a) Case I - D=0.5 cm, H=1 cm (H/D=1:2) b) Case II - D=0.4 cm, H=0.8 cm (H/D=1:2) Case I: - Pin fins of diameter 5 mm with a height of 10 mm. The area added by the fins accounts to 1.766 sq.cm by each pin fin. Therefore the total area added by 4 pins for Case I is 7.065 sq.cm Case II: - Pin fins of diameter 4 mm with a height of 8 mm. The area added by the fins accounts to 1.1304 sq.cm by each pin fin. Therefore the total area added by 4 pins for Case I is 4.5216 sq.cm
4.1 Streamlines of Case I & Case II as Compared to Smooth Surface
From fig 7.16 it is seen that the flow does not produce any type of whirls while taking the turn. It is also evident that the flow interacts with the pin fins at the corners thus enhancing the heat transfer of the tip at the corners as well as over the other surface.
(a)
(b)
(c) Fig 9 a) Streamlines of smooth surface at Re=200000 b) Streamlines of pin finned surface Case I at Re=200000 c) Streamlines of pin finned surface Case II at Re=200000
4.2 Velocity Vectors of the Three Surfaces
(a)
(b)
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(c) Fig 10 Velocity Vectors of three surface at Re=450000 Fig 10 shows the velocity vectors of smooth tip two pass channel and pin finned tip two pass channel. It can be clearly seen that due to the pin fins turbulence is created at the corners of the tip region. The flow interacts with surface of the tip due to the pins and also remains near the pins for a considerable amount of time. After heating there is time for the flow to mix with the incoming cooling fluid, thereby improving cooling at the tip section.
4.3 Comparisons of the Three Surfaces
(a)
(b)
(c) Fig 11.a) Nusselts number comparison of three surfaces b) Pressure drop comparison of three surfaces c) Heat transfer coefficient comparison of three surfaces From fig 11 it can be seen that the values of Nusselts number and surface heat transfer coefficient are greater for the pin finned surfaces as compared to the smooth surface. The pressure drop values are alost same for all the three surfaces.
5. CONCLUSIONS
From the above studies the following conclusions can be made
Pin fins can prove to be a great heat transfer enhancement tool if configured in proper numbers and arrangement.
Compared to the smooth surface the pin finned surfaces provided an additional area for heat transfer.
The pin fins provided at the corners and at the periphery of the tip force the vortices generated towards the tip wall thereby improving the turbulent mixing of the heated fluid with the incoming cold fluid.
The pin fins provided also helped in uniform distribution of heat over the tip.
The heat transfer enhancement of the pin finned surfaces is about 1.5 times higher than that of the smooth surface.
All the augmentation has been obtained at a pressure drop of less than 10 %.
REFERENCES
[1] Ronald S. Bunker,” The Augmentation of Internal Blade Tip-Cap Cooling by Arrays of Shaped Pins,” Journal of Turbomachinery, OCTOBER 2008, Vol. 130 / 041007-1
[2] Gongnan Xie, Bengt Sundén.” Numerical predictions of augmented heat transfer of an internal blade tip-wall by hemispherical dimples,” International Journal of Heat and Mass Transfer 53 (2010) 5639–5650.
[3] Gongnan Xie, Bengt Sundén, “Computational Analysis of Pin-Fin Arrays Effects on Internal Heat
0
200
400
600
800
1000
1200
200000
300000
350000
450000
Nusselts Number Nu
Reynolds Number Re
Smooth Surface
Case I
Case II
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
200000
300000
350000
450000
Pressure drop Δp
Reynolds Number Re
Smooth surface
Case I
Case II
0
100
200
300
400
200000
300000
350000
450000
h
Reynolds Number
Smooth Surface
Case I
Case II
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Transfer Enhancement of a Blade Tip Wall,” Journal of Heat Transfer, MARCH 2010, Vol. 132 / 031901- 1
[4] Gongnan Xie, Bengt Sundén,Weihing Zhang,“Comparisons of Pins/Dimples,Protrusions cooling concepts for a turbine blade tip wall at high Reynolds numbers,” Journal of Heat Transfer, June 2011,Vol.133/061902-1
[5] Robert KIML, Sadanari MOCHIZUKI, Akira MURATA and Matej SULITKA, “Rib-Induced Secondary Flow Structures inside a High Aspect Ratio Trapezoidal Channel,” Proceedings of the International Gas Turbine Congress 2003 Tokyo November 2-7, 2003.
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