International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of mechanical and civil engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in mechanical and civil engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
STUDY OF HEAT TRANSFER ON BROKEN ARC ROUGHNESS ELEMENTS ON THE ABSORBER PLATE...IAEME Publication
Performance of solar air heater can be enhanced by adding roughness to the inner periphery. The present study on the effect of various shape parameters for broken arc roughness elements of heat transfer and friction factor characteristics of rectangular duct. The duct has Reynolds number (Re) range of 3000-22300, respective roughness height (e/D) values is 0.045, arc angle (α) is 60˚ and roughness width (W/w) is 5 and relatively roughness pitch is 8.
Natural convection heat transfer inside inclined open cylinderIAEME Publication
This document summarizes an experimental study on natural convection heat transfer inside an inclined open cylinder. The study investigated the effects of inclination angle (0°, 30°, 60°, 90°) and heat flux (70-600 W/m2) on the heat transfer. Empirical correlations were developed relating the average Nusselt number to the Rayleigh number. Results showed that heat transfer, as measured by the local and average Nusselt number, increased with increasing heat flux and inclination angle from horizontal to vertical.
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.
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 an experimental study on heat transfer enhancement from surface roughness at laminar flow. Specifically, it examines using circular and oval dimples on an aluminum plate to increase heat transfer from the plate to air flowing over it at Reynolds numbers from 600 to 2000. The study finds that both circular and oval dimples enhance heat transfer compared to a flat plate, while maintaining equivalent or lower pressure drops. The experimental results are validated by comparing the measured Nusselt numbers to theoretical values for a plain vertical plate under laminar flow conditions. In general, the dimpled surfaces increase thermal performance without significantly increasing pressure drops compared to a smooth surface.
FLUID FLOW ANALYSIS IN AIR DUCT FLOW WITH AND WITHOUT INTERNAL THREADS USING ...IAEME Publication
Computational heat transfer flow modeling is one of the great challenges in the classical sciences. As with most problems in engineering, the interest in the heat transfer augmentation is increasing due to its extreme importance in various industrial applications. This paper deals with the analysis of heat transfer for fluid flowing through the pipe with and without internal threads using CFD. Using CFD codes for modeling the heat and fluid flow is an efficient tool for predicting equipment performance. CFD offers a convenient means to study the detailed flows and heat exchange processes, which take place inside the tube. Simulations were carried out using commercial CFD software ANSYS Fluent version 14.5. Friction factor and Nusselt number for air flowing through the specified tube (internal diameter = 0.005 m, length = 0.1 m) were obtained first for the plain tube and then for the tube with internal threads with pitch 5mm in the Reynolds number range of 2000 to 5000. Finally results will be compared to available experimental and analytical calculations. The data obtained by simulation are matching with the literature value for a plain tube with the discrepancy of less than plus or minus 5% for Nusselt number and for the friction factor.
Enhanced heat transfer for the tube with internal threads has been observed. Heat flux is more uniform all along the tube and decreases uniformly towards the center.
A Review on Enhancement of Heat Transfer Rate by Various Passive MethodsIRJET Journal
This document reviews various passive methods that have been used to enhance heat transfer rates in heat exchangers. It summarizes 15 research papers that studied techniques like using corrugated tubes, twisted tapes, nanofluids, and ribbed surfaces to increase heat transfer surface area and turbulence. Computational fluid dynamics simulations and experiments on different heat exchanger designs found that these passive methods can increase heat transfer rates by up to 60% while also increasing pressure drop. The optimal designs and flow conditions depended on factors like geometry, Reynolds number, and mass flow rates. Overall, passive inserts and surface modifications were shown to effectively enhance heat transfer in heat exchangers.
IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of mechanical and civil engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in mechanical and civil engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
STUDY OF HEAT TRANSFER ON BROKEN ARC ROUGHNESS ELEMENTS ON THE ABSORBER PLATE...IAEME Publication
Performance of solar air heater can be enhanced by adding roughness to the inner periphery. The present study on the effect of various shape parameters for broken arc roughness elements of heat transfer and friction factor characteristics of rectangular duct. The duct has Reynolds number (Re) range of 3000-22300, respective roughness height (e/D) values is 0.045, arc angle (α) is 60˚ and roughness width (W/w) is 5 and relatively roughness pitch is 8.
Natural convection heat transfer inside inclined open cylinderIAEME Publication
This document summarizes an experimental study on natural convection heat transfer inside an inclined open cylinder. The study investigated the effects of inclination angle (0°, 30°, 60°, 90°) and heat flux (70-600 W/m2) on the heat transfer. Empirical correlations were developed relating the average Nusselt number to the Rayleigh number. Results showed that heat transfer, as measured by the local and average Nusselt number, increased with increasing heat flux and inclination angle from horizontal to vertical.
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.
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 an experimental study on heat transfer enhancement from surface roughness at laminar flow. Specifically, it examines using circular and oval dimples on an aluminum plate to increase heat transfer from the plate to air flowing over it at Reynolds numbers from 600 to 2000. The study finds that both circular and oval dimples enhance heat transfer compared to a flat plate, while maintaining equivalent or lower pressure drops. The experimental results are validated by comparing the measured Nusselt numbers to theoretical values for a plain vertical plate under laminar flow conditions. In general, the dimpled surfaces increase thermal performance without significantly increasing pressure drops compared to a smooth surface.
FLUID FLOW ANALYSIS IN AIR DUCT FLOW WITH AND WITHOUT INTERNAL THREADS USING ...IAEME Publication
Computational heat transfer flow modeling is one of the great challenges in the classical sciences. As with most problems in engineering, the interest in the heat transfer augmentation is increasing due to its extreme importance in various industrial applications. This paper deals with the analysis of heat transfer for fluid flowing through the pipe with and without internal threads using CFD. Using CFD codes for modeling the heat and fluid flow is an efficient tool for predicting equipment performance. CFD offers a convenient means to study the detailed flows and heat exchange processes, which take place inside the tube. Simulations were carried out using commercial CFD software ANSYS Fluent version 14.5. Friction factor and Nusselt number for air flowing through the specified tube (internal diameter = 0.005 m, length = 0.1 m) were obtained first for the plain tube and then for the tube with internal threads with pitch 5mm in the Reynolds number range of 2000 to 5000. Finally results will be compared to available experimental and analytical calculations. The data obtained by simulation are matching with the literature value for a plain tube with the discrepancy of less than plus or minus 5% for Nusselt number and for the friction factor.
Enhanced heat transfer for the tube with internal threads has been observed. Heat flux is more uniform all along the tube and decreases uniformly towards the center.
A Review on Enhancement of Heat Transfer Rate by Various Passive MethodsIRJET Journal
This document reviews various passive methods that have been used to enhance heat transfer rates in heat exchangers. It summarizes 15 research papers that studied techniques like using corrugated tubes, twisted tapes, nanofluids, and ribbed surfaces to increase heat transfer surface area and turbulence. Computational fluid dynamics simulations and experiments on different heat exchanger designs found that these passive methods can increase heat transfer rates by up to 60% while also increasing pressure drop. The optimal designs and flow conditions depended on factors like geometry, Reynolds number, and mass flow rates. Overall, passive inserts and surface modifications were shown to effectively enhance heat transfer in heat exchangers.
EXPERIMENTAL STUDY ON THE ANALYSIS OF HEAT ENHANCEMENT IN CORRUGATED TWISTED ...P singh
In heat exchanger, the enthalpy is transferred between two or more fluids, at different temperatures. The major challenge in designing a heat exchanger is to make the equipment more compact and achieve a high heat transfer rate using minimum pumping power. In recent years, the high cost of energy and material has resulted in an increased effort aimed at producing more efficient heat exchange equipment. Furthermore, as a heat exchanger becomes older, the resistance to heat transfer increases owing to fouling or scaling. The heat transfer rate can be improved by introducing a disturbance in the fluid flow thereby breaking the viscous and thermal boundary layer. However, in the process pumping power may increase significantly and ultimately the pumping cost becomes high. Therefore, to achieve a desired heat transfer rate in an existing heat exchanger at an economic pumping power, several techniques have been proposed in recent years and are discussed under the classification section.
In this work, a study of transient heat transfer in double tube heat exchanger has enhanced. The inner tube of the setup was made with corrugation on both inner and outer walls by twisting the pipe from one end, which gives the more swirling motion to the fluid particles flowing over it. The flow inside the pipe was considered as turbulent, and the analysis was done experimentally and theoretically by using the ANSYS workbench. The experimental results were compared with the experimental values taken in the setup done by considering the inner tube as normal pipe. In both heat exchangers the values were taken and compared with the theoretical analysis. Temperature distribution and heat transfer rate were calculated and the details of the study have been discussed in this paper.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
A Review on Heat Transfer Improvent of Plate Heat ExchangerIJERA Editor
Plate heat exchanger has found a wide range of application in various industries like food industries, chemical industries, power plants etc. It reduces the wastage of energy and improves the overall efficiency of the system. Hence, it must be designed to obtain the maximum heat transfer possible. This paper is presented in order to study the various theories and results given over the improvement of heat transfer performance in a plate heat exchanger. However, there is still a lack in data and generalized equations for the calculation of different parameters in the heat exchanger. It requires more attention to find out various possible correlations and generalized solutions for the performance improvement of plate heat exchanger.
This document describes an experimental study of heat transfer in a rectangular duct with and without internal V-shaped ribs. Experiments were conducted with air flow in turbulent regime (Reynolds numbers 3000-18000) in smooth duct and ducts with continuous or discrete internal V-shaped ribs. Temperature and pressure measurements were taken to determine heat transfer coefficients and friction factors for different configurations. Results showed that continuous ribs enhanced heat transfer more than discrete ribs, but also increased pressure drop more substantially. Heat transfer enhancement was dependent on rib geometry and position.
Numerical Analysis of Heat Transfer Enhancement in Pipe-inPipe Helical Coiled...iosrjce
This document presents a numerical analysis of heat transfer enhancement in pipe-in-pipe helical coiled heat exchangers. Computational fluid dynamics (CFD) was used to analyze the effect of varying parameters like inner tube diameter, mass flow rates, and flow configuration (parallel vs. counter flow). The results show that overall heat transfer coefficients increase with increasing inner Dean number and mass flow rates. Heat transfer rates also increase with higher inner mass flow rates. Counter flow configuration provides better heat transfer than parallel flow. Increasing the inner tube size decreases the total heat transfer rate due to a reduction in annulus cross-sectional area. Measured inner Nusselt numbers agree reasonably well with existing correlations.
IRJET- Effect of Wavy Tube on Heat Transfer in a Concentric Tube Heat Exch...IRJET Journal
This document provides a review of research on using a wavy inner tube in a concentric tube heat exchanger to enhance heat transfer. It first discusses different heat transfer augmentation techniques, including active, passive and compound methods. It then reviews several previous studies that experimentally and numerically examined heat transfer performance of wavy tube heat exchangers. These studies found that a wavy inner tube could increase heat transfer by over 100% compared to a plain tube by generating swirl flow and turbulence. The document also reviews research on other passive techniques like wire coil inserts and their effects on heat transfer and pressure drop. Overall, the review shows that wavy tube and other passive inserts can significantly enhance heat transfer in heat exchangers.
Experimental analysis of heat transfer enhancementin circulariaemedu
This document summarizes an experimental study on enhancing heat transfer in a circular double tube heat exchanger using rectangular inserts. Air was passed through the inner tube while hot water flowed through the outer tube. Heat transfer coefficients and friction factors were determined for the plain tube and with inserts. The results showed that heat transfer was enhanced by 0.9 to 1.9 times with the inserts due to flow disruption, while friction factors increased by 1 to 1.7 times. Heat transfer coefficients increased with Reynolds number whereas friction factors decreased. Validation experiments on a plain tube agreed well with theoretical predictions within 10% uncertainty.
This document describes a computational fluid dynamics (CFD) analysis of natural convection flow through a square cavity using ANSYS software. The study investigates laminar natural convection heat transfer in two-dimensional vertical air cavities for a range of Rayleigh numbers from 103 to 106 and an aspect ratio of 1. The geometry of the square cavity is created and meshed in ANSYS. Steady-state simulations are performed using the finite volume method. Boundary conditions of isothermal side walls and adiabatic top and bottom walls are applied. Contour plots and streamlines of velocity and temperature are analyzed to understand heat transfer trends. Nusselt number correlations as a function of Rayleigh number are proposed based
1) The document presents an experimental study of heat transfer through a uniformly heated vertical tube air heater.
2) The study investigates the effect of tube length, diameter, and heat flux on heat transfer and buoyancy induced airflow.
3) It was found that the heat transfer coefficient increases with increasing heat flux but decreases with increasing tube diameter and length, while air outlet temperature increases with tube length and heat flux but decreases with diameter.
Heat exchangers are used widely in industrial application such as chemical,
food processing, power production, refrigeration and air-conditioning
industries. Helical coiled heat exchangers are used in order to obtain a large
heat transfer per unit volume and to enhance the heat transfer rate on the inside
surface. In the present study, CFD simulations are carried out for a counter
flow tube in tube helical heat exchanger where hot water flows through the
inner tube and cold water flows through the outer tube. From the simulation
results heat transfer coefficient, pressure drop and nusselt number are
calculated. The heat transfer characteristics of the same are compared with that
of a counter flow tube in tube straight tube heat exchanger of same length
under same temperature and flow conditions. CFD simulation results showed
that the helical tube in tube heat exchanger is more effective than the straight
tube in tube heat exchanger.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
An Experimental Research on Heat Transfer Enhancement of a Circular Tube with...IRJESJOURNAL
ABSTRACT:- In the literature, internal tube baffles are widely studied. There is a lack of data for baffles mounted on outside of the tubes. This study aims to fill this gap. Therefore, the effect of baffle inclination angles on heat transfer improvement has been studied experimentally. The experiments were carried out for forced convection of air on a circular tube with inclined baffles. Air has been used as the cold fluid. Experimental results for eight different velocities of air flow (2 – 20 m/s) are presented. Pitch between baffles is 12 mm.The baffle inclination angles with respect to the tube axis were 45º, 60º and 80º. Water temperature is fixed as 65 °C. According to the experimental results, the baffles with an inclination angle of 45º enhance the heat transfer over 60º and 80º around 13.7 % and 10.5 %, respectively. However, pressure drop values for 45º and 60º are 18 % higher than pressure drop values for 80º. The empirical correlations of the Nusselt number have also been obtained for each angle.
This document summarizes an experimental study on heat transfer and flow friction characteristics of a solar water heater with inserted baffles inside tubes. The study found that inserting full-length baffles inside tubes enhanced heat transfer and improved solar water heater performance compared to plain tubes. Maximum collector efficiency and outlet fluid temperature occurred at 12:45 hours for both baffled and plain tubes, but values were higher for baffled tubes. Friction factor was also lower for the baffled tube design at the point of maximum outlet temperature. The baffled tube design improved heat transfer and solar water heater performance relative to the plain tube design.
IRJET- Experimental Analysis of Convective Heat Transfer Augmentation of Bi-M...IRJET Journal
This document provides a literature review of research on bi-metallic plate heat exchangers to enhance convective heat transfer. It discusses 8 studies that experimentally analyzed heat transfer coefficients and pressure drops of different combinations of bi-metallic plates under forced convection. The goal of improving heat transfer efficiency while minimizing pressure losses is important for industries using such heat exchangers like power plants, refrigeration, and chemical processes. The document focuses on reviewing work done to optimize the design of bi-metallic heat exchangers.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document discusses a study on the fatigue analysis of glass fiber reinforced composites. It describes how glass fiber reinforced epoxy laminate composite samples were manufactured using vacuum bagging technique. The samples were then cut and tested under varying cyclic loads on a fatigue testing machine. The results showed that the glass fiber reinforced composites could withstand fatigue loads efficiently compared to aluminum and the number of cycles before failure decreased as the applied load increased. The document concludes that future work could extend these tests under different loading conditions to improve stress variation understanding and enable application in aircraft structures.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Los planes departamentales de agua y saneamiento básico buscan mejorar la coordinación entre entidades para planificar e implementar proyectos de agua potable, alcantarillado y saneamiento básico a nivel regional. Estos planes pueden mejorar la cobertura y calidad de los servicios, pero también representan desventajas como la pérdida de autonomía municipal y mayores tarifas para los consumidores.
Las instrucciones describen cómo hacer velas de colores usando sal teñida y tizas de cera. Se instruye rayar las tizas de cera y mezclarlas con sal teñida de colores, luego derretir la mezcla y verterla en moldes para que se endurezca en velas de colores personalizadas.
EXPERIMENTAL STUDY ON THE ANALYSIS OF HEAT ENHANCEMENT IN CORRUGATED TWISTED ...P singh
In heat exchanger, the enthalpy is transferred between two or more fluids, at different temperatures. The major challenge in designing a heat exchanger is to make the equipment more compact and achieve a high heat transfer rate using minimum pumping power. In recent years, the high cost of energy and material has resulted in an increased effort aimed at producing more efficient heat exchange equipment. Furthermore, as a heat exchanger becomes older, the resistance to heat transfer increases owing to fouling or scaling. The heat transfer rate can be improved by introducing a disturbance in the fluid flow thereby breaking the viscous and thermal boundary layer. However, in the process pumping power may increase significantly and ultimately the pumping cost becomes high. Therefore, to achieve a desired heat transfer rate in an existing heat exchanger at an economic pumping power, several techniques have been proposed in recent years and are discussed under the classification section.
In this work, a study of transient heat transfer in double tube heat exchanger has enhanced. The inner tube of the setup was made with corrugation on both inner and outer walls by twisting the pipe from one end, which gives the more swirling motion to the fluid particles flowing over it. The flow inside the pipe was considered as turbulent, and the analysis was done experimentally and theoretically by using the ANSYS workbench. The experimental results were compared with the experimental values taken in the setup done by considering the inner tube as normal pipe. In both heat exchangers the values were taken and compared with the theoretical analysis. Temperature distribution and heat transfer rate were calculated and the details of the study have been discussed in this paper.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
A Review on Heat Transfer Improvent of Plate Heat ExchangerIJERA Editor
Plate heat exchanger has found a wide range of application in various industries like food industries, chemical industries, power plants etc. It reduces the wastage of energy and improves the overall efficiency of the system. Hence, it must be designed to obtain the maximum heat transfer possible. This paper is presented in order to study the various theories and results given over the improvement of heat transfer performance in a plate heat exchanger. However, there is still a lack in data and generalized equations for the calculation of different parameters in the heat exchanger. It requires more attention to find out various possible correlations and generalized solutions for the performance improvement of plate heat exchanger.
This document describes an experimental study of heat transfer in a rectangular duct with and without internal V-shaped ribs. Experiments were conducted with air flow in turbulent regime (Reynolds numbers 3000-18000) in smooth duct and ducts with continuous or discrete internal V-shaped ribs. Temperature and pressure measurements were taken to determine heat transfer coefficients and friction factors for different configurations. Results showed that continuous ribs enhanced heat transfer more than discrete ribs, but also increased pressure drop more substantially. Heat transfer enhancement was dependent on rib geometry and position.
Numerical Analysis of Heat Transfer Enhancement in Pipe-inPipe Helical Coiled...iosrjce
This document presents a numerical analysis of heat transfer enhancement in pipe-in-pipe helical coiled heat exchangers. Computational fluid dynamics (CFD) was used to analyze the effect of varying parameters like inner tube diameter, mass flow rates, and flow configuration (parallel vs. counter flow). The results show that overall heat transfer coefficients increase with increasing inner Dean number and mass flow rates. Heat transfer rates also increase with higher inner mass flow rates. Counter flow configuration provides better heat transfer than parallel flow. Increasing the inner tube size decreases the total heat transfer rate due to a reduction in annulus cross-sectional area. Measured inner Nusselt numbers agree reasonably well with existing correlations.
IRJET- Effect of Wavy Tube on Heat Transfer in a Concentric Tube Heat Exch...IRJET Journal
This document provides a review of research on using a wavy inner tube in a concentric tube heat exchanger to enhance heat transfer. It first discusses different heat transfer augmentation techniques, including active, passive and compound methods. It then reviews several previous studies that experimentally and numerically examined heat transfer performance of wavy tube heat exchangers. These studies found that a wavy inner tube could increase heat transfer by over 100% compared to a plain tube by generating swirl flow and turbulence. The document also reviews research on other passive techniques like wire coil inserts and their effects on heat transfer and pressure drop. Overall, the review shows that wavy tube and other passive inserts can significantly enhance heat transfer in heat exchangers.
Experimental analysis of heat transfer enhancementin circulariaemedu
This document summarizes an experimental study on enhancing heat transfer in a circular double tube heat exchanger using rectangular inserts. Air was passed through the inner tube while hot water flowed through the outer tube. Heat transfer coefficients and friction factors were determined for the plain tube and with inserts. The results showed that heat transfer was enhanced by 0.9 to 1.9 times with the inserts due to flow disruption, while friction factors increased by 1 to 1.7 times. Heat transfer coefficients increased with Reynolds number whereas friction factors decreased. Validation experiments on a plain tube agreed well with theoretical predictions within 10% uncertainty.
This document describes a computational fluid dynamics (CFD) analysis of natural convection flow through a square cavity using ANSYS software. The study investigates laminar natural convection heat transfer in two-dimensional vertical air cavities for a range of Rayleigh numbers from 103 to 106 and an aspect ratio of 1. The geometry of the square cavity is created and meshed in ANSYS. Steady-state simulations are performed using the finite volume method. Boundary conditions of isothermal side walls and adiabatic top and bottom walls are applied. Contour plots and streamlines of velocity and temperature are analyzed to understand heat transfer trends. Nusselt number correlations as a function of Rayleigh number are proposed based
1) The document presents an experimental study of heat transfer through a uniformly heated vertical tube air heater.
2) The study investigates the effect of tube length, diameter, and heat flux on heat transfer and buoyancy induced airflow.
3) It was found that the heat transfer coefficient increases with increasing heat flux but decreases with increasing tube diameter and length, while air outlet temperature increases with tube length and heat flux but decreases with diameter.
Heat exchangers are used widely in industrial application such as chemical,
food processing, power production, refrigeration and air-conditioning
industries. Helical coiled heat exchangers are used in order to obtain a large
heat transfer per unit volume and to enhance the heat transfer rate on the inside
surface. In the present study, CFD simulations are carried out for a counter
flow tube in tube helical heat exchanger where hot water flows through the
inner tube and cold water flows through the outer tube. From the simulation
results heat transfer coefficient, pressure drop and nusselt number are
calculated. The heat transfer characteristics of the same are compared with that
of a counter flow tube in tube straight tube heat exchanger of same length
under same temperature and flow conditions. CFD simulation results showed
that the helical tube in tube heat exchanger is more effective than the straight
tube in tube heat exchanger.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
An Experimental Research on Heat Transfer Enhancement of a Circular Tube with...IRJESJOURNAL
ABSTRACT:- In the literature, internal tube baffles are widely studied. There is a lack of data for baffles mounted on outside of the tubes. This study aims to fill this gap. Therefore, the effect of baffle inclination angles on heat transfer improvement has been studied experimentally. The experiments were carried out for forced convection of air on a circular tube with inclined baffles. Air has been used as the cold fluid. Experimental results for eight different velocities of air flow (2 – 20 m/s) are presented. Pitch between baffles is 12 mm.The baffle inclination angles with respect to the tube axis were 45º, 60º and 80º. Water temperature is fixed as 65 °C. According to the experimental results, the baffles with an inclination angle of 45º enhance the heat transfer over 60º and 80º around 13.7 % and 10.5 %, respectively. However, pressure drop values for 45º and 60º are 18 % higher than pressure drop values for 80º. The empirical correlations of the Nusselt number have also been obtained for each angle.
This document summarizes an experimental study on heat transfer and flow friction characteristics of a solar water heater with inserted baffles inside tubes. The study found that inserting full-length baffles inside tubes enhanced heat transfer and improved solar water heater performance compared to plain tubes. Maximum collector efficiency and outlet fluid temperature occurred at 12:45 hours for both baffled and plain tubes, but values were higher for baffled tubes. Friction factor was also lower for the baffled tube design at the point of maximum outlet temperature. The baffled tube design improved heat transfer and solar water heater performance relative to the plain tube design.
IRJET- Experimental Analysis of Convective Heat Transfer Augmentation of Bi-M...IRJET Journal
This document provides a literature review of research on bi-metallic plate heat exchangers to enhance convective heat transfer. It discusses 8 studies that experimentally analyzed heat transfer coefficients and pressure drops of different combinations of bi-metallic plates under forced convection. The goal of improving heat transfer efficiency while minimizing pressure losses is important for industries using such heat exchangers like power plants, refrigeration, and chemical processes. The document focuses on reviewing work done to optimize the design of bi-metallic heat exchangers.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document discusses a study on the fatigue analysis of glass fiber reinforced composites. It describes how glass fiber reinforced epoxy laminate composite samples were manufactured using vacuum bagging technique. The samples were then cut and tested under varying cyclic loads on a fatigue testing machine. The results showed that the glass fiber reinforced composites could withstand fatigue loads efficiently compared to aluminum and the number of cycles before failure decreased as the applied load increased. The document concludes that future work could extend these tests under different loading conditions to improve stress variation understanding and enable application in aircraft structures.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Los planes departamentales de agua y saneamiento básico buscan mejorar la coordinación entre entidades para planificar e implementar proyectos de agua potable, alcantarillado y saneamiento básico a nivel regional. Estos planes pueden mejorar la cobertura y calidad de los servicios, pero también representan desventajas como la pérdida de autonomía municipal y mayores tarifas para los consumidores.
Las instrucciones describen cómo hacer velas de colores usando sal teñida y tizas de cera. Se instruye rayar las tizas de cera y mezclarlas con sal teñida de colores, luego derretir la mezcla y verterla en moldes para que se endurezca en velas de colores personalizadas.
The document discusses best practices for customer service in social media, specifically for the Allegro social media group. It provides 10 commandments or guidelines for social media customer service on Allegro, including responding to messages quickly, working as a team, being honest, speaking in a way customers can understand, treating each customer individually, and not separating complaints from positive interactions. The presentation aims to improve social media customer service.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
Este documento explora el tema de la publicidad, definiéndola de varias maneras y discutiendo tanto sus ventajas como desventajas. También analiza cómo la publicidad funciona para fabricantes, empresas de servicios y desde perspectivas económica, conservadora e informativa.
El documento contrasta las diferencias entre ángeles y amigos, señalando que mientras los ángeles son asignados por Dios para cuidarnos, los amigos nos toman de la mano y nos acercan a Dios por amor. También explica que los amigos comparten nuestras alegrías, sueños y triunfos, y viven por nosotros, mientras que los ángeles observan desde la distancia y cumplen una misión celestial. En última instancia, concluye que aunque un ángel quisiera ser nuestro amigo, un amigo también puede ser
O documento descreve um evento de dois dias sobre gestão do conhecimento e redes sociais em ambientes corporativos. O programa inclui discussões sobre estratégias de redes sociais corporativas, compartilhamento de conhecimento em mídias sociais e construção de narrativas digitais. O objetivo é promover a interação entre participantes por meio de casos reais e dinâmicas para aprendizagem prática.
Primeira vez que o termo Saúde Funcional é colocado oficialmente no escopo do Conselho Municipal de Saúde de Santos - 13 de março de 1998. Esse foi o primeiro passo para a Política Nacional de Saúde Funcional.
Este documento describe cómo investigar y utilizar analizadores de protocolos de red. Explica que estos analizadores capturan y decodifican paquetes de red para identificar problemas y comportamientos inusuales. Luego recomienda descargar e instalar el analizador Windump y muestra algunos de sus usos como filtrar tráfico por puerto, protocolo o host.
La Unión Europea ha acordado un paquete de sanciones contra Rusia por su invasión de Ucrania. Las sanciones incluyen restricciones a las transacciones con bancos rusos clave y la prohibición de la venta de aviones y equipos a Rusia. Los líderes de la UE esperan que las sanciones aumenten la presión económica sobre Rusia y la disuadan de continuar su agresión contra Ucrania.
This program cannot be run in DOS mode. The document appears to be computer code or system information related to running a program in different operating modes. It provides technical details but no higher level context about the purpose or functionality of the program.
Este documento proporciona información sobre juegos de computadora gratuitos que los niños y adolescentes pueden descargar legalmente, incluyendo detalles sobre el tipo de juegos y los requisitos técnicos. También advierte a los lectores revisar los juegos antes de descargar para evitar virus y sugiere evitar juegos para adultos.
O documento discute um projeto de lei que acaba com o monopólio da Caixa Econômica Federal nos contratos de loterias federais, permitindo que lotéricas façam acordos com outras instituições financeiras. O projeto também aumenta o percentual de retorno das apostas de 9% para 11% e define regras mínimas para a remuneração dos lotéricos. O deputado Beto Mansur, autor do projeto, afirma que as novas regras incentivarão o empreendedorismo das lotéricas.
Effect of Wavy Tube on Heat Transfer in a Concentric Tube Heat Exchanger: A R...IRJET Journal
This document provides a review of research on using a wavy inner tube in a concentric tube heat exchanger to enhance heat transfer. Several studies have found that a wavy inner tube can increase the Nusselt number, friction factor, and thermal performance factor compared to a plain inner tube. Computational fluid dynamics simulations have also validated that wavy fins and tubes promote longitudinal vortices that augment heat transfer, while transverse vortices have a negative effect. Overall, experiments and models show that a wavy inner tube can enhance heat transfer in a concentric tube heat exchanger by over 100% in some cases.
CFD Analysis for Heat Transfer Enhancement of a Corrugated Plate Heat Exchang...ijtsrd
The flow properties of heat transfer across such corrugated channels are very distinct from parallel plate channels. The primary flow direction is parallel to the waviness of the channel of the corrugated channel, although the local flow direction is still changed due to the waviness of the channel. By flow recirculation, separation and re attachment, the thermal boundary layer formed on its walls is regularly disrupted and the convective heat transfer coefficient is thus increased. In this work, in corrugated channels, the convective heat transfer and pressure drop characteristics of flow have been tested numerically. On channels of uniform heat flux and fixed corrugation over a Reynolds number spectrum, 10000 = Re = 30000, numerical research was conducted. The impacts of channel configuration, variation in Reynold’s number, and concentration variations of nanoparticles in base fluid on heat transfer are discussed. As opposed to the traditional corrugated channel, a major heat transfer gain was associated with the proposed corrugated channel. Based on the nanofluid concentration, Reynold number and channel configuration of the corrugated channel, the average Nusselt number increased by a factor of 2.2 up to 2.8 compared to that of the semi circular corrugated channel. Compared with the effect of channel configuration variation, triangular corrugated channel was the best Nusselt numbers, followed by the shape Semi circular Triangular , and Semi circular corrugated channel with the lowest results. Prof. Pushparaj Singh | Rishi Kesh Jha "CFD Analysis for Heat Transfer Enhancement of a Corrugated Plate Heat Exchanger using Different Corrugated Channel Configurations" 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/ijtsrd35706.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/35706/cfd-analysis-for-heat-transfer-enhancement-of-a-corrugated-plate-heat-exchanger-using-different-corrugated-channel-configurations/prof-pushparaj-singh
15. experimental investigation of heat transfer characteristics ofNEERAJKUMAR1898
1) The document describes an experimental investigation of heat transfer characteristics of a trapezoidal channel with a sharp edged wavy plate.
2) The study measured heat transfer and pressure drop for different plate configurations including a plane plate, trapezoidal plate, and trapezoidal plate with a sharp edged wavy plate.
3) The results showed that the trapezoidal plate and plate with a sharp edge increased heat transfer compared to the plane plate, with the sharp edged wavy plate configuration providing the highest enhancement of up to 85% in heat transfer.
CFD Analysis of Concentric Tube Heat Exchanger Using Twisted TapesIJARIIT
In this paper, the three dimensional CFD modeling studies on heat transfer, friction factor and thermal performance
of concentric tube heat exchanger using twisted tapes (Plain, V-cut, , Jagged V-cut) with different twist ratios (y=2.0, 4.0) are
used. Twisted tapes are used to augment the heat transfer by creating turbulence in the fluid flow. Various methods are applied
to increase thermal performance of heat transfer devices such as treated surfaces, rough surfaces, swirling flow devices, coiled
tubes, and surface tension devices. Out of these twisted tape method is used to increase the thermal performance. Twisted tape
inserts on effectiveness of heat exchanger has analyzed for different Reynolds Number. The maximum thermal performance
factor was obtained by the Jagged V-cut twisted tape (H=50) insert compare to other twisted tapes. Simultaneously the friction
factor has been analyzed
This document summarizes a research project that aims to thermally enhance a plate-fin heat exchanger using secondary structures called cross-cuts. Cross-cuts are sections removed from fins perpendicular to airflow to disrupt boundary layer development. The project will test various cross-cut configurations and validate correlations from a previous study. A plate-fin heat sink will be compared to designs with one and two cross-cuts. The goal is to validate that a single cross-cut provides the best thermal performance improvement of 4-13% over the base design within a pumping power range of 0.01-1W.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Irjet v4 i12326Effect of External Threaded Inside Tube on Heat Transfer Rate ...IRJET Journal
This document reviews the use of an internal threaded tube in a concentric tube heat exchanger to enhance heat transfer rates. It discusses how passive heat transfer augmentation techniques like threaded tubes can increase turbulence and disrupt boundary layers to improve heat transfer efficiency. The review analyzes previous studies that experimentally compared heat transfer performance and pressure drop between plain and threaded inner tubes. Results indicated that threaded tubes increased heat transfer coefficients and Reynolds numbers while potentially reducing fouling compared to plain tubes. Further experimentation and CFD simulation were proposed to validate theoretical predictions and determine the threaded tube design's feasibility for applications like radiators and air conditioners.
A brief review on mixed convection heat transfer in channel flow with vortex ...IJERA Editor
In an effort to increase processor speeds, 3D IC architecture is being aggressively pursued by researchers and
chip manufacturers. This architecture allows extremely high level of integration with enhanced electrical
performance and expanded functionality, and facilitates realization of VLSI and ULSI technologies. However,
utilizing the third dimension to provide additional device layers poses thermal challenges due to the increased
heat dissipation and complex electrical interconnects among different layers. The conflicting needs of the
cooling system requiring larger flow passage dimensions to limit the pressure drop, and the IC architecture
necessitating short interconnect distances to reduce signal latency warrant paradigm shifts in both of their
design approach. Additional considerations include the effects due to temperature non-uniformity, localized
hot spots, complex fluidic connections, and mechanical design. This paper reviews the advances in electronic
chip cooling in the last decade and provides a vision for code signing integrated cooling systems. For various
heat fluxes on each side of a chip acting as discrete heat source, the current single-phase cooling technology is
projected to provide adequate cooling, albeit with high pressure drops. Effectively mitigating the high
temperatures surrounding local hot spots remains a challenging issue. Various forms of tabulators above the
chips, different geometric arrangements of the chips positioned top and bottom wall of the duct serves very
well in the heat augmentation technique with better performance
Heat transfer enhancement_fusion reactor.pdfSandeepRimza1
jet impingement technique with a sectorial extended surface (SES) concept for the modular heliumcooled
divertor has been studied within the framework of the post ITER tokamak, at the Institute for
plasma research (IPR), INDIA. Experimental and numerical studies have been conducted to predict the
thermal-hydraulic performance of a finger-type divertor design with proposed SES. Critical thermal
hydraulic parameters, effective heat transfer coefficient and pressure loss have been measured in the
experiment for the reference divertor as well as for a divertor with SES. The experimental mock-ups are
made to full scale respecting Reynolds and Prandtl number similarities. Air is used as the simulant to
represent helium, which is used as the coolant in prototype. A novel heat concentrator has been
developed to simulate the high heat flux, by electrical heating.
This document summarizes a study on the thermal analysis of circular inclined pipes subjected to natural convection using computational fluid dynamics (CFD). The study investigated the effect of parameters like tube diameter, heat supplied, and tube inclination on the temperature and heat transfer coefficient through experimental testing and CFD analysis. The experimental results were validated against CFD results, with less than 5% error found between the two. It was found that temperature increased with increasing pipe diameter and heat supply. The temperature was also strongly influenced by heat flux and diameter, and weakly dependent on tube inclination.
HEAT TRANSFER AUGMENTATION IN A PLATE-FIN HEAT EXCHANGER: A REVIEWIAEME Publication
The improvement of the performance of heat exchangers with gas as the working fluid becomes particularly important due to the high thermal resistance offered by gases in general. In order to compensate for the poor heat transfer properties of gases, the surface area density of plate heat exchangers can be increased by making use of the secondary fins such as, off-set fins, triangular fins, wavy fins, louvered fins etc. In addition, a promising technique for the enhancement of heat transfer is the use of longitudinal vortex generators. The longitudinal vortices are produced due to the pressure difference generated between the front and back surface of the vortex generator.
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.
NUMERICAL ANALYSIS OF THERMAL PERFORMANCE OF LOUVER FINijiert bestjournal
Louver fins are widely used in heat exchanger for a utomotive applications such as radiator,intercooler,condenser,heater core etc. This study presents numerical analysis of effect of variation of louver pitch on heat transfer rate of louver fins. The three dimensional governing equations for fluid flow and heat transfe r are solved using ANSYS Fluent 14.5 for air flow of 4 m/s to 9 m/s. The variations of t emperature,pressure and heat transfer rate are studied using computational model. The enhancem ent of heat rate is observed as louver pitch is reduced.
Enhancement of Heat Transfer and Thermo-Hydraulic Performance Using Triangula...IJERA Editor
Solar heat has been thrust area of research to explore renewable energy utilisation for the past few decades. In
solar air heaters artificial roughness is tried on the surface of the absorber plate by adding small roughness
elements to enhance the heat transfer rate. In the present work triangular protrusion are provided to act as
roughness elements over the surface of the aluminum absorber plate. The experimental study is carried out on
the effect of change in apex angle of protrusions on the heat transfer rate by keeping the other design parameters
unchanged. Maximum heat transfer rate and thermo-hydraulic performance between the range of apex angle 300
and 600 is studied. The Nusselt number is between 50 and 110, friction factor 4.5-6.7x10-3, Stanton number is 6-
14x10-3. The heat transfer rate and thermo-hydraulic performance are observed to be maximum for 450 apex
angle and least for the 600 plate.
EXPERIMENTAL STUDY OF HEAT TRANSFER FROM PLATE FIN ARRAY IN MIXED CONVECTION ...ijiert bestjournal
The document presents an experimental study on mixed convection heat transfer from plate fin arrays. Experiments were conducted on 9 plate fins attached to a 150mm by 150mm aluminum base plate. Temperature measurements were taken at varying fan velocities and input powers to determine heat transfer coefficients and relationships between parameters like Nusselt number, Reynolds number, and Grashof number. Key findings included that plate fins provided better heat transfer performance than solid pins, and the dimensionless parameter Gr/Re2 could be used to identify the mixed convection heat transfer region.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
The heat transfer and friction factor were
experimentally investigated in a louvered strip inserted tube in
turbulent flow region. A copper tube of (I.D=28mm, O.D=32mm)
and 900mm length was used. A louvered strip insert with
different geometrical configuration was inserted into the smooth
tube. A uniform heat flux condition was created by wrapping
heating tape of 2500 watt around the test section. Fibre glass
cloth was used as a thermal insulator which surrounds the
heating tape. Outer surface temperature of the tube were
measured at five different equally spaced points of test section by
k-typethermocouples. Two thermocouples were used to measure
the inlet and outlet temperature of water. The Reynolds numbers
were varied in the range of 2500 to 4000 with constant heat flux
of 24 kw/m2 for smooth tube and louvered strip inserted. Nusselt
number and friction factor obtained for louvered strip (with
forward backward arrangement) > Nusselt number and friction
factor for louvered strip (with semi-forward semi-backward
arrangement)> Nusselt number and friction factor for louvered
strip (with forward arrengement).
experimental investigation of heat transfer intensification of pin fins under...INFOGAIN PUBLICATION
Recent development era in technology has huge requirement of high performance lightweight, and compact heat transfer equipment. To accomplish this demand fins are widely used as effective elements for heat transfer enhancement. One of the commonly used heat exchanger fins is the pin fin which offers an economical and trouble free solution in many situations. This is more important in cooling of air conditioning equipment, thermal power plants, gas turbine blade, aerospace industry, combustion chamber liners, and biomedical devices, electrical and electronic component. Therefore now a day’s industries are utilizing thermal system with pin fins and analyse the various influencing parameters on performance of pin fin of different geometry under force convection. The turbulence occurred due to these techniques are good enough to enhance heat transfer rate. This article is focused on comprehensive review of work carried out in this technology.
This document summarizes research on heat transfer augmentation techniques in circular and non-circular tubes. Both active and passive methods are used, with passive methods not requiring external power. For circular tubes, research is reviewed on using displaced inserts like twisted tapes and wire coil inserts in laminar and turbulent flow. Heat transfer enhancement of up to 36% was achieved in laminar flow and up to 9.8 times in turbulent flow compared to plain tubes. Computational fluid dynamics (CFD) analysis was also used to study flow and heat transfer with inserts. For non-circular tubes, heat transfer in ducts with triangular, rectangular, and trapezoidal cross-sections was investigated.
Experimental Investigation of a Dimpled Plate by Natural Convection Heat Tran...IRJET Journal
This document summarizes previous research on using dimpled surfaces to enhance heat transfer via natural convection. It begins by defining natural convection and explaining how dimpled surfaces promote turbulence and vortex formation, augmenting heat transfer. The document then reviews several studies that experimentally investigated heat transfer over dimpled plates and tubes. Most found that heat transfer increased with dimple density, depth, and Reynolds number. The objectives of the proposed new study are to analyze heat transfer from vertically heated dimpled plates with variations in dimple shape, size, and arrangement. It is hypothesized that dimpled plates will enhance thermal performance over smooth plates through increased surface area and reduced flow separation.
Building Production Ready Search Pipelines with Spark and MilvusZilliz
Spark is the widely used ETL tool for processing, indexing and ingesting data to serving stack for search. Milvus is the production-ready open-source vector database. In this talk we will show how to use Spark to process unstructured data to extract vector representations, and push the vectors to Milvus vector database for search serving.
Infrastructure Challenges in Scaling RAG with Custom AI modelsZilliz
Building Retrieval-Augmented Generation (RAG) systems with open-source and custom AI models is a complex task. This talk explores the challenges in productionizing RAG systems, including retrieval performance, response synthesis, and evaluation. We’ll discuss how to leverage open-source models like text embeddings, language models, and custom fine-tuned models to enhance RAG performance. Additionally, we’ll cover how BentoML can help orchestrate and scale these AI components efficiently, ensuring seamless deployment and management of RAG systems in the cloud.
Full-RAG: A modern architecture for hyper-personalizationZilliz
Mike Del Balso, CEO & Co-Founder at Tecton, presents "Full RAG," a novel approach to AI recommendation systems, aiming to push beyond the limitations of traditional models through a deep integration of contextual insights and real-time data, leveraging the Retrieval-Augmented Generation architecture. This talk will outline Full RAG's potential to significantly enhance personalization, address engineering challenges such as data management and model training, and introduce data enrichment with reranking as a key solution. Attendees will gain crucial insights into the importance of hyperpersonalization in AI, the capabilities of Full RAG for advanced personalization, and strategies for managing complex data integrations for deploying cutting-edge AI solutions.
TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
- The top challenges for privacy leaders, practitioners, and organizations in 2024
- Key themes to consider in developing and maintaining your privacy program
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
Climate Impact of Software Testing at Nordic Testing DaysKari Kakkonen
My slides at Nordic Testing Days 6.6.2024
Climate impact / sustainability of software testing discussed on the talk. ICT and testing must carry their part of global responsibility to help with the climat warming. We can minimize the carbon footprint but we can also have a carbon handprint, a positive impact on the climate. Quality characteristics can be added with sustainability, and then measured continuously. Test environments can be used less, and in smaller scale and on demand. Test techniques can be used in optimizing or minimizing number of tests. Test automation can be used to speed up testing.
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...Neo4j
Leonard Jayamohan, Partner & Generative AI Lead, Deloitte
This keynote will reveal how Deloitte leverages Neo4j’s graph power for groundbreaking digital twin solutions, achieving a staggering 100x performance boost. Discover the essential role knowledge graphs play in successful generative AI implementations. Plus, get an exclusive look at an innovative Neo4j + Generative AI solution Deloitte is developing in-house.
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und überflüssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
In the rapidly evolving landscape of technologies, XML continues to play a vital role in structuring, storing, and transporting data across diverse systems. The recent advancements in artificial intelligence (AI) present new methodologies for enhancing XML development workflows, introducing efficiency, automation, and intelligent capabilities. This presentation will outline the scope and perspective of utilizing AI in XML development. The potential benefits and the possible pitfalls will be highlighted, providing a balanced view of the subject.
We will explore the capabilities of AI in understanding XML markup languages and autonomously creating structured XML content. Additionally, we will examine the capacity of AI to enrich plain text with appropriate XML markup. Practical examples and methodological guidelines will be provided to elucidate how AI can be effectively prompted to interpret and generate accurate XML markup.
Further emphasis will be placed on the role of AI in developing XSLT, or schemas such as XSD and Schematron. We will address the techniques and strategies adopted to create prompts for generating code, explaining code, or refactoring the code, and the results achieved.
The discussion will extend to how AI can be used to transform XML content. In particular, the focus will be on the use of AI XPath extension functions in XSLT, Schematron, Schematron Quick Fixes, or for XML content refactoring.
The presentation aims to deliver a comprehensive overview of AI usage in XML development, providing attendees with the necessary knowledge to make informed decisions. Whether you’re at the early stages of adopting AI or considering integrating it in advanced XML development, this presentation will cover all levels of expertise.
By highlighting the potential advantages and challenges of integrating AI with XML development tools and languages, the presentation seeks to inspire thoughtful conversation around the future of XML development. We’ll not only delve into the technical aspects of AI-powered XML development but also discuss practical implications and possible future directions.
AI 101: An Introduction to the Basics and Impact of Artificial IntelligenceIndexBug
Imagine a world where machines not only perform tasks but also learn, adapt, and make decisions. This is the promise of Artificial Intelligence (AI), a technology that's not just enhancing our lives but revolutionizing entire industries.
Let's Integrate MuleSoft RPA, COMPOSER, APM with AWS IDP along with Slackshyamraj55
Discover the seamless integration of RPA (Robotic Process Automation), COMPOSER, and APM with AWS IDP enhanced with Slack notifications. Explore how these technologies converge to streamline workflows, optimize performance, and ensure secure access, all while leveraging the power of AWS IDP and real-time communication via Slack notifications.
“An Outlook of the Ongoing and Future Relationship between Blockchain Technologies and Process-aware Information Systems.” Invited talk at the joint workshop on Blockchain for Information Systems (BC4IS) and Blockchain for Trusted Data Sharing (B4TDS), co-located with with the 36th International Conference on Advanced Information Systems Engineering (CAiSE), 3 June 2024, Limassol, Cyprus.
Threats to mobile devices are more prevalent and increasing in scope and complexity. Users of mobile devices desire to take full advantage of the features
available on those devices, but many of the features provide convenience and capability but sacrifice security. This best practices guide outlines steps the users can take to better protect personal devices and information.
National Security Agency - NSA mobile device best practices
E351923
1. Dhananjay R.Giramet al. Int. Journal of Engineering Research and Application www.ijera.com
Vol. 3, Issue 5, Sep-Oct 2013, pp.19-23
www.ijera.com 19 | P a g e
Experimental &Theoretical Analysis Of Heat Transfer
Augmentation From Dimpled Surface
Dhananjay R.Giram1
, A.M.Patil 2
1M.E.Reasearch Scholar, PVPIT, Budhgaon,
2 Professor, Vice Principal, PVP Institute of Technology, Budhgaon
ABSTRACT
In the present work the heat transfer characteristics and the pressure drop of the forced convection apparatus of
six dimpled plates is studied. Six test plates with varying dimple densities; by varying the input voltage Nusselt
No. variation was recorded. It is found that Nusselt No. increases as the dimple density increases .Also it was
found that percentage increase in Nusselt No. is greater for staggered dimple arrangement. The sample
experimental results obtained are presented in graphical forms as shown in Figure shows the calculated results
based on the observations to show the comparative Nusselt numbers enhancements with that obtained with
different parameters combinations.
Dimpled typical technique that offers a higher heat transfer increase at the cost of mild pressure drop penalty.
This study investigates the heat transfer characteristics of Plate with dimpled surface. Over the past couple of
years the focus on using concavities or dimples provides enhanced heat transfer has been documented by a
number of researchers.
I. NOMENCLATURE
A Effective heat transfer surface area , m2
Cp Specific heat at constant pressure for the air,
Jkg-1
K-1
Cd Coefficient of discharge for orifice
D Pipe diameter ,m
d Orifice Diameter, m
g Acceleration of gravity, msec-1
H Height of test plate, m
h Convection heat transfer coefficient, Wm-2
K-1
K Thermal conductivity of gas, Wm-1
K-1
L Characteristics length of plate, mm
m Mass flow rate, kg/s
Nu Nusselt number
Nuo Nusselt number obtained for plain plate
Nu18 Nusselt number obtained dimpled plate with
18 number of dimples
Nu20 Nusselt number obtained dimpled plate with
20 number of dimples
Nu30 Nusselt number obtained dimpled plate with
22 number of dimples
Nu50 Nusselt number obtained dimpled plate with
24 number of dimples
Nu56 Nusselt number obtained dimpled plate with
33 number of dimples
Nu/Nuo Baseline Nusselt number ratio
q Heat transfer rate, W/m2
Re Reynolds number
T Temperature, o
C
Tb Mean bulk temperature, o
C
Tin Air inlet temperature, o
C
Tout Air outlet temperature, o
C
Ts Average surface temperature, o
C
w Width of test plate, mm
II. INTRODUCTION
Extensive research effort has been focused on
reducing the consumption of nonrenewable energy.
Improving the efficiency of the universal process of
heat exchange is one such area which continues to
attract a lot of attention. Enhancing the efficiency of
heat transfer is useful in a variety of practical
applications such as macro and micro scale heat
exchangers, gas turbine internal airfoil cooling, fuel
elements of nuclear power plants, powerful
semiconductor devices, electronic cooling, combustion
chamber liners, biomedical devices, etc. Compact heat
exchangers and gas turbine internal airfoil cooling are
two applications which have been the subject of study
for a number of researchers over the recent years.
Compact heat exchangers are used extensively
in the trucking industry as radiators to reduce the
excess thermal energy. Improved efficiency of compact
heat exchangers can permit smaller radiators leading to
smaller frontal area and thus can lead to substantial fuel
saving. In a compact heat exchanger there are three
important aspects of heat transfer. The first aspect to
consider is the convection of heat from the fluid to the
tube wall of the heat exchanger. The heat is then
conducted through the walls of the tube. Finally, the
heat is removed from the tube surface by convection to
the air flowing through it. Air-side resistance to heat
transfer in compact heat exchangers comprises between
70-80 percent of the total resistance and hence any
improvement in the efficiency of a compact heat
exchangers is focused on augmenting the air side
convective heat transfer.
Heat exchangers are widely used in various
thermal power plants, means of transport, heating and
RESEARCH ARTICLE OPEN ACCESS
2. Dhananjay R.Giramet al. Int. Journal of Engineering Research and Application www.ijera.com
Vol. 3, Issue 5, Sep-Oct 2013, pp.19-23
www.ijera.com 20 | P a g e
air conditioning systems, electronic equipment’s, and
space vehicles. In all these applications, improvements
in the efficiency of heat exchangers can lead to
substantial cost, space and material savings. Therefore,
considerable research work has been done in the past to
seek effective ways to increase the efficiency of heat
exchangers [10].
The study of improved heat transfer
performance is referred to as heat transfer
enhancement, augmentation, or intensification. In
general, this means an increase in heat transfer
coefficient. For both single-phase and two-phase heat
transfer, effective heat transfer enhancement techniques
have been reported. However, in the present work wire
coils inserts are used in the inner tube to increase heat
transfer rate.
Use of dimpled surface can significantly
intensify the heat transfer enhancement. Some typical
wire insert are water tube boilers, condensers,
evaporators, radiators, heat exchangers in chemical and
textile industries, compact heat exchangers etc. Using
coil wire insert tubes not only increase the swirl flow
but also reduce the hydrodynamic resistance for the
fluid flow over the surface. The swirls formed inside
the tube results in thinning and disturbing the thermal
boundary layer formed over the surface during coolant
flow and hence, increasing the turbulence. And serve
ultimately to bring about enhancement of heat transfer
between the fluid and its neighboring surface at the
price of less increase in pressure penalty.
III. LITERATURE REVIEW
A variety of experimental and analytical
works has been carried out on enhancement of heart
transfer. Especially the heat transfer enhancement by
forced convection have concerned by many researcher
and practitioners. Relevant literature pertaining to this
title reviewed from different points is as below:
R.K.Ali[1] investigated experimentally the
heat transfer from a heat source simulating an
electronic chip mounted on a printed circuit board
placed downstream of a guide fence on the lower wall
of the flow passage with two different aspect ratios
(H/W = 0.3 and 1). The channel height to the heat
source height ratios (H/B) are of 10 and 3. The effect of
the guide fence height (b) and the spacing between the
guide fence and the heat source (S) were investigated.
The guide fence was orientated such that guide fence
extension point was varied from the midpoint of the
front face of the heat source to the endpoint of the side
face at 5000 6 ReL 6 30,000. The results for the heat
source without guide fence displayed noticeable
difference when compared with the flow over smooth
plate placed on the lower wall of the flow passage. An
enhancement in the convective heat transfer coefficient
up to 20% is obtained when decreasing the flow
passage height to the heat source height ratio from 10
to 3. Also, higher Nusselt number is located at the front
face and the vertical sides of the heat source compared
with that of the top surface. Nusselt number increases
with the increase in both Reynolds number and the
guide fence height while the effect of spacing between
the guide fence and the heat source depending on the
guide fence height. Correlations for the average Nusselt
number were obtained utilizing the present
measurements within the investigated range of the
different parameters.
Arthur Bergles[2] investigated Phase-change
processes, such as pool and flow boiling, are generally
very effective modes of heat transfer. However, the
demands of modern thermal systems have required the
development of methods to enhance boiling systems.
While heat fluxes above 108W/m2 have been
accommodated in carefully controlled situations, the
required fluid and the convective conditions usually
dictate maximum heat fluxes several orders of
magnitude lower. Two major contemporary areas,
enhanced surfaces for pool boiling and enhanced
surfaces and inserts for forced convection boiling
/vaporization, are discussed, as they facilitate the
attainment of high heat fluxes. In addition to these
passive techniques, active techniques and compound
techniques are mentioned. The taxonomy of enhanced
heat transfer is covered, and recommendations are
given for future work.
Yaroslav Chudnovsky[3] investigated vortex
heat transfer enhancement of heat transfer by a system
of 3D surface cavities (dimples) having specific
geometry, dimensions and mutual orientation Each
dimple acts as a “vortex generator” which provides an
intensive and stable heat and mass transfer between the
dimpled surface and gaseous heating media. The
obtained method includes mixing of the fluid by
creating artificial surface such as dimples or other
techniques.
Qiuwang Wang , Qiuyang Chen, Ling
Wang[4] studied technique to enhance heat transfer in
cooling channels of plate-type fuel elements in reactor
cores, the experimental research is conducted on the
heat transfer and pressure drop in horizontal narrow
rectangular channels with mounted longitudinal vortex
generators (LVGs) for water flow with Prandtl number
Pr = 4–5. The parameters examined were: flow velocity
from 0.5 to 3.4 m/s, Reynolds number from 3000 to
20,000, heat flux 43.6 kW/m2, maximum system
pressure 1.3 atm, and viscosity ratio from 1.05 to 1.2. It
is found that the LVGs could greatly improve the heat
transfer rate by 10–45%. Thermal performance is
compared under three constraints, i.e., identical mass
flow rate (IMF), identical pressure drop(IPD) and
identical pumping power (IPP). It is found that the heat
transfer performance of channel with LVGs on two
sides are better than those on one side. Application of
LVGs to plate-type fuel element is a potential
technique for next generation advanced nuclear reactors
concepts.
Srinath V. Ekkad , David Kontrovitz [5]has
presented detailed heat transfer distributions are
presented over a jet impingement target surface with
dimples. Jet impingement by itself is an extremely
3. Dhananjay R.Giramet al. Int. Journal of Engineering Research and Application www.ijera.com
Vol. 3, Issue 5, Sep-Oct 2013, pp.19-23
www.ijera.com 21 | P a g e
effective heat transfer enhancement technique. This
study investigates the effect of jet impingement on a
target surface with a dimple pattern. The effect of
dimple location, underneath the jets or between the jets,
is investigated. The effect of dimple depth is also
investigated. The average jet Reynolds number is
varied from 4800 to 14 800. The heat transfer
measurements are obtained using the transient liquid
crystal technique. Results for dimpled target surfaces
are normalized with data for plane target surfaces to
determine whether the presence of dimples enhances
heat transfer. Results show that the presence of dimples
on the target surface, in-line or staggered with respect
to jet location, produce lower heat transfer coefficients
than the non-dimpled target surface. The bursting
phenomena associated with flow over dimples produces
disturbances of the impingement jet structures resulting
in lower levels of heat transfer coefficients on the target
surface.
A.Slanciauskas [6]studied the effect of
roughness elements on heat transfer in fluids is
different from their effect in gases because of the
different thermal resistance of the viscous sub layer.
The distinctive feature of the process was examined in
every detail and generalized by two rules deduced, one
for fluids with Pr> 5 and another for gases. For fluids,
small equally dispersed roughness elements can disturb
the viscous sub layer sufficiently. For gases, the
enhancement is reached by creation of many
reattachment zones after obstacles. Two- to three-fold
heat transfer enhancement within the limits of Reynolds
analogy is attainable.
IV. EXPERIMENTAL SET UP
Fig: Experimental Setup
Blower is used to supply air. The heat
exchange module developed, was connected to air flow
bench to force the air parallel to the dimpled test
surface. The strip plate heater fixed at the bottom of the
test plate, was connected to power socket through
dimmer stat. Dimmer stat readings were varied to give
the required heat input to the test plate. Calibrated
Copper-Constantan thermocouple wires were used to
measure the temperatures. Provisions were made to fix
the thermocouple junction on the test surface.
Temperatures of air at inlet and outlet of the heat
exchange module are also measured Digital
temperature indicators were used to show the
temperature readings (in o
C) recorded by thermocouple
wires. Photo shows the image of experimental set-up.
V. EXPERIMENTAL PROCEDURE
In this section the procedure for the
experimentation is outlined thoroughly. As mentioned
in the earlier sections seven mild steel plates of
dimensions 150x100x12 mm3
were fabricated. Six
plates were dimpled with different dimple densities and
schemes of dimple arrangements, using round nose
tool. Tests for forced convection heat transfer
measurement were decided to conduct on the plain and
dimpled surfaces. Plate heater was fixed at the bottom
of the test plate. The depth of the dimple was kept as 3
mm to maintain δ/D ratio as 0.33. Later on depth of
dimple was increased to 4 mm to give δ/D ratio as 0.41.
The procedure for experimentation used is explained
stepwise as follows
1. Switch on both the temperature indicators to
ensure that both of them indicate accurate
temperature readings initially.
2. Start the power supply to heater at required
dimmer stat reading.
3. After achieving a suitable temperature (say 60o
C)
at the test surface, ensure that temperatures
recorded at all the test surface points are same.
Start the blower to force the air flow over the test
surface.
4. Adjust the regulating valve manually to adjust the
mass flow rate of air to indicate the desired
pressure differential reading on water manometer.
5. After achieving the steady state condition note
down temperatures at different points on test
surface, inlet and outlet air temperatures and
pressure drop readings across the test section.
6. The readings are checked for repeatability.
7. For the same heat input to the test surface, repeat
the procedure for flow rates of air i.e. at 04 cm, 06
cm and 08 cm of water column difference.
8. Change the heat input by varying dimmer stat
readings and repeat the whole procedure. The
dimmer stat readings were varied as 60 Volts, 80
Volts and 100 Volts .
9. The same procedure is repeated for the all test
plates.
VI. MATHEMATICAL MODELLING
Ts =((T1+T2+T3+T4+T5)/5) ,
Ta= ((Tai+Tao)/2)
Q = Cd
22
21
a2a1
ρ
ρ
2gH1aa
w
,
m = ρ Q
4. Dhananjay R.Giramet al. Int. Journal of Engineering Research and Application www.ijera.com
Vol. 3, Issue 5, Sep-Oct 2013, pp.19-23
www.ijera.com 22 | P a g e
m = ρ a1V, V=
1ρa
m
, Re =
μ
ρVd 1
q = h As (Ts-Tbm) = m Cp (T6 – T7) h =
)T-(TA
)T-(TCm
bmss
76p
Nu =
k
dh 1
, ƒ =
1
2
d
L
2
ρV
P
0
100
200
300
400
500
600
700
3688 4400 5030 5968
NusseltNo(Nu)
Reynolds No(Re)
Nu00
Nu18
Nu50
Figure 2: Reynold number v/s Nusselt number
VII. RESULTS AND DISCUSSION
Looking to the nature of the curves, it is found
that plate with 50 dimples is having highest average
heat transfer coefficient and hence highest average
Nusselt number, in all the heat input conditions in the
range of Reynolds number from 3688 to 5968.
VIII. CONCLUSION
The main conclusions are summarized as:
1. Heat transfer rate from the test surface increases with
increase in mass flow rate of flowing fluid and heat
input.
2. The use of dimples on the surface results in heat
transfer augmentation in forced convection heat
transfer with lesser pressure drop penalty.
3. The value of maximum Nusselt number obtained for
staggered arrangement of dimples is greater than that
for inline arrangement, keeping all other parameters
constant. It shows that for heat transfer enhancement
staggered arrangement is more effective than the inline
arrangement.
4. At all Reynolds number considered Nusselt number
augmentation increases as the dimple density of test
plates increases (all other experimental and geometric
parameters are kept constant).This is because the more
number of dimples produce:(i) increase in the strength
and intensity of vortices and associated secondary
flows ejected from the dimples (ii) increases in the
magnitudes of three-dimensional turbulence production
and turbulence transport. But the percent increase in
Nusselt number enhancement per unit percent increase
in area decreases beyond a particular value of dimple
density. More number of dimples beyond a particular
value is believed to trap fluid which then acts as a
partially insulating pocket to decrease the rate of
Nusselt number enhancement with increase in further
dimple density. It also results in decrease in rate of
Nusselt number enhancement after a certain value of
dimple density of plate (here 22 numbers of dimples for
staggered arrangement and 24 numbers of dimples for
inline arrangement). Thus it can be commented that the
optimum value of dimple density lies in between 22
and 33 numbers of dimples for staggered arrangement
and in between 24 and 35 for inline arrangement of
dimples on the considered surface area.
5. At all Reynolds number considered Nusselt number
augmentation increases with increase in dimple depth
.But the rate of increase in Nusselt number per unit
increase in surface area are low after increasing the
dimple depth beyond a certain value. This is attributed
to larger region of stronger re-circulating flow
developed due to dipper dimple. The strong
recirculating flows produced believe to trap the fluid
which again acts as partially insulating zones results in
lowering the rate of increase of Nusselt number
enhancement. This concludes that there lies a optimum
value of dimple depth and corresponding δ/D value
where the rate of Nusselt number enhancement is
maximum
IX. SUGGESTIONS FOR FUTURE
WORK
1. In the present work experiments were carried for
limited and low range of Reynolds number. This could
be extended for the higher range of Reynolds number
and using larger dimensions of the test surface.
2. Different shapes like rectangular or triangular shapes
of dimples can be used instead of circular dimples on
the test surface.
3. Performance of combination of above mentioned
shaped dimples can be experimented and compared.
4. Test plate material can be changed such as copper
(which is very good conductor of heat) and
performance is compared with different material
combinations
X. ACKNOWLEDGEMENTS
The authors are thankful to the Principal of
SKN Sinhgad College of Engineering, Pandharpur for
giving all support for completing the work.
REFERENCES
5. Dhananjay R.Giramet al. Int. Journal of Engineering Research and Application www.ijera.com
Vol. 3, Issue 5, Sep-Oct 2013, pp.19-23
www.ijera.com 23 | P a g e
[1] R.K.Ali 2009 Elsevier Inc “ Augmentation
of heat transfer from heat source placed
downstream a guide”
[2] Arthur E. Bergles “ high-flux processes
through enhanced heat transfer”
[3] Yaroslav Chudnovsky 2004 AI ChESpring
Technical Meeting “vortex heat transfer
enhancement for chemical industry fired
heaters
[4] Qiuwang Wang , Qiuyang Chen, Ling Wang ,
Min Zeng, Yanping Huang, Zejun Xiao ,2006
Elsevier “ Experimental study of heat transfer
enhancement in narrow rectangular channel
with longitudinal vortex generators”
[5] Srinath V. Ekkad , David Kontrovitz 2002
Elsevier Science “jet impingement heat
transfer on dimpled target surfaces”
[6] A.Slanciauskas oct1999 Elsevier “Two
friendly rules for the turbulent heat transfer
enhancement”
[7] Juin chen . 2001 Elsevier Science “Heat
transfer enhancement in dimpled tubes.”
[8] Y. Chen M. Fiebig N. K.Mitra March 1998
“ Heat transfer enhancement of a finned oval
tube with punched longitudinal vortex
generators in-line”
[9] Betul Ayhan Sarac Tulin Bali , March 2007
“An experimental study on heat transfer and
pressure drop characteristics of decaying swirl
flow through a circular pipe with a vortex
generator
[10] M.R. Shaeri, M. Yaghoubi 2009 Elsevier
“Numerical analysis of turbulent convection
heat transfer from an array of perforated fins”
[11] Moon H.K., T. O’Connell, Glezer B.,
“Channel Height Effect on Heat Transfer and
Friction in a Dimpled Passage”, ASME J. Gas
Turbine and Power, 122, April 2000, pp.307-
313.
[12] Kuethe A. M., 1971, ‘‘Boundary Layer
Control of Flow Separation and Heat
Exchange,’’ US Patent No. 3,578,264