In this paper heat transfer in single phase through micro-channels was studied. The validation of classical correlations of conventional channels to micro-channels is explored. It is found that classical approach is in good agreement with the experimental results of heat transfer in micro-channels .The material used for micro-channel heat sink (MCHS) is copper, experiments were conducted using water as cooling agent in
this study. Micro-channels are made with the help of EDM machine on the upper surface of MCHS. Variation of heat transfer rates, effect of friction factor, effect of pressure drop and variation in temperature distribution is investigated in this study. It is observed in the study that with decrease in
velocity flow friction also decreases.
NUMERICAL INVESTIGATION OF LAMINAR NANOFLUID FLOW IN MICRO CHANNEL HEAT SINKS IAEME Publication
The effect of using nanofluids on heat transfer and aerodynamics characteristics in rectangular shaped micro channel heat sink (MCHS) is numerically investigated for Reynolds number range of (100-400 ) and different value of heat flux (50 , 100, 150 ) / . In this study,the MCHS performance using tow type of nanofluid with volume
fraction 10% was used as a coolant is examined. The three-dimensional steady, laminar flow and heat transfer governing equations are solved using The computational fluid dynamics code (FLUENT). The MCHS performance is evaluated in terms of temperature profile, heat transfer,velocity profile, pressure drop and friction factor.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
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.
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.
EXPERIMENTAL INVESTIGATION ON BOILING HEAT TRANSFER USING R134AJournal For Research
The heat transfer characteristic of R134a during boiling were experimentally investigated in a horizontal mini channels. The experiments used different parameters like saturation temperature, mass flux, vapour quality, channel diameter, channel geometry and thermo physical properties on the heat transfer coefficients. Several literatures are used to find a assessment correlations and experimental analysis to prepare an experimental setup and their results validation. Boiling heat transfer correlations and theoretical solutions are used to predict the experimental data in this research.
Evaluation of Convective Heat Transfer Coefficient of Air Flowing Through an ...Bishal Bhandari
The heat transfer coefficient is the most influential parameter in designing of the ducts. The heat transfer coefficient varies with varying velocity, inclination and heat input. The nature of the graph of the convective heat transfer coefficient for a different velocity of air and at a different inclination of the circular Duct was plotted and the result was discussed.
Experimental Study of Heat Transfer Analysis in Vertical Rod Bundle of Sub Ch...IJMER
The ability of the fluid in taking the heat generated by the nuclear reactor fuel is one
important aspect of reactor safety. These capabilities must be kept high enough to maintain integrity of
the fuel cladding as inside retaining radioactive substances. Study characteristics of forced convection in
the fluid water using seven vertical cylinders heated uniformly in the composition ratio of hexagons with
Pitch/Diameter (P/D) at 1.58 in the hexagon-shaped shell model of the reactor core test equipment in
order to obtain the correlation equation displacement convection force. In this study, the heat flux and
velocity of fluid flow greatly affect the temperature of the fluid. The greater the heat flux given the fluid
temperature is getting higher because of the greater heat flux on the cylinder heating the heat absorbed
by the fluid is also getting bigger. Similarly, the velocity of fluid flow, increasing the velocity of the fluid
flow, the smaller the fluid temperature because by increasing the velocity of fluid flow in the sub channel
the heat received by the fluid on the wane led to the smaller fluid temperature. Heat transfer coefficient
results obtained at a velocity flow of 0.1 m s-1
is 500 Wm-2K
-1
to 23 500 Wm-2K
-1
, at a velocity flow of 0.3
m s
-1
is 3 100 Wm-2K
-1
up to 2 800 Wm-2K
-1
and in velocity flow of 0.5 m s-1
is 3 500 Wm-2K
-1
to 32 500
Wm-2K
-1
. In this experimental study use forced convection flow has a Reynolds number range from 3 991
to 29 537 and Graetz numbers from 1 371 to 41 244. The correlation of forced convection heat transfer as
follows: Nu forced = 1.641 Gz 0.4267
NUMERICAL INVESTIGATION OF LAMINAR NANOFLUID FLOW IN MICRO CHANNEL HEAT SINKS IAEME Publication
The effect of using nanofluids on heat transfer and aerodynamics characteristics in rectangular shaped micro channel heat sink (MCHS) is numerically investigated for Reynolds number range of (100-400 ) and different value of heat flux (50 , 100, 150 ) / . In this study,the MCHS performance using tow type of nanofluid with volume
fraction 10% was used as a coolant is examined. The three-dimensional steady, laminar flow and heat transfer governing equations are solved using The computational fluid dynamics code (FLUENT). The MCHS performance is evaluated in terms of temperature profile, heat transfer,velocity profile, pressure drop and friction factor.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
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.
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.
EXPERIMENTAL INVESTIGATION ON BOILING HEAT TRANSFER USING R134AJournal For Research
The heat transfer characteristic of R134a during boiling were experimentally investigated in a horizontal mini channels. The experiments used different parameters like saturation temperature, mass flux, vapour quality, channel diameter, channel geometry and thermo physical properties on the heat transfer coefficients. Several literatures are used to find a assessment correlations and experimental analysis to prepare an experimental setup and their results validation. Boiling heat transfer correlations and theoretical solutions are used to predict the experimental data in this research.
Evaluation of Convective Heat Transfer Coefficient of Air Flowing Through an ...Bishal Bhandari
The heat transfer coefficient is the most influential parameter in designing of the ducts. The heat transfer coefficient varies with varying velocity, inclination and heat input. The nature of the graph of the convective heat transfer coefficient for a different velocity of air and at a different inclination of the circular Duct was plotted and the result was discussed.
Experimental Study of Heat Transfer Analysis in Vertical Rod Bundle of Sub Ch...IJMER
The ability of the fluid in taking the heat generated by the nuclear reactor fuel is one
important aspect of reactor safety. These capabilities must be kept high enough to maintain integrity of
the fuel cladding as inside retaining radioactive substances. Study characteristics of forced convection in
the fluid water using seven vertical cylinders heated uniformly in the composition ratio of hexagons with
Pitch/Diameter (P/D) at 1.58 in the hexagon-shaped shell model of the reactor core test equipment in
order to obtain the correlation equation displacement convection force. In this study, the heat flux and
velocity of fluid flow greatly affect the temperature of the fluid. The greater the heat flux given the fluid
temperature is getting higher because of the greater heat flux on the cylinder heating the heat absorbed
by the fluid is also getting bigger. Similarly, the velocity of fluid flow, increasing the velocity of the fluid
flow, the smaller the fluid temperature because by increasing the velocity of fluid flow in the sub channel
the heat received by the fluid on the wane led to the smaller fluid temperature. Heat transfer coefficient
results obtained at a velocity flow of 0.1 m s-1
is 500 Wm-2K
-1
to 23 500 Wm-2K
-1
, at a velocity flow of 0.3
m s
-1
is 3 100 Wm-2K
-1
up to 2 800 Wm-2K
-1
and in velocity flow of 0.5 m s-1
is 3 500 Wm-2K
-1
to 32 500
Wm-2K
-1
. In this experimental study use forced convection flow has a Reynolds number range from 3 991
to 29 537 and Graetz numbers from 1 371 to 41 244. The correlation of forced convection heat transfer as
follows: Nu forced = 1.641 Gz 0.4267
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.
Numerical Analysis of Heat Transfer Enhancement in Pipe-inPipe Helical Coiled...iosrjce
These paper focuses on the effect of the inside tubes at constant value of mass flow rate and variation
of annulus mass flow rate on effect of Dean Number and overall heat transfer coefficient with constant wall
temperature, CFD analysis of a helically coiled heat exchanger. Also deals with the effect of Dean Number with
respect to Reynolds Number and Nusselt Number and Overall Heat Transfer coefficient on change of coil
configuration of helically coiled tube. The particular difference in this study in comparison with the other
similar studies was the boundary conditions for the helical coils. The results indicate that with the decrease the
inner coil diameter, the overall heat transfer coefficient is increased
Thermal analysis of various duct cross sections using altair hyperworks softwaresushil Choudhary
In this work thermal analysis and comparison of various duct cross sections is done computationally using Altair
Hyperworks Software. Simple Analytical results were obtained for conduction and convection through the ducts
which can be used to build up thermal circuit. The inner surface of all ducts is maintained at constant
temperature and ambient air is at certain temperature that is less than inner surface temperature of pipe. Due to
temperature difference heat will flow from higher temperature to lower temperature. Due to temperature
difference heat will flow from higher temperature to lower temperature. The material of pipe provides
conductive resistance and air provides convective resistance. Hence this is a mix mode of heat transfer. The heat
transfer takes place in one dimension only and properties are considered to be isotropic. The ducts are assumed
to be made of aluminium having known thermal conductivity and density. The surroundings of ducts have
known convective heat transfer coefficient and temperature. The results are obtained on hyperview which are for
heat flux, temperature gradient and grid temperature. The different characteristics can be obtained by varying the
material of the ducts.
Heat Transfer Analysis of Refrigerant Flow in an Evaporator TubeIJMER
the paper aim is to presenting the heat transfer analysis of refrigerant flow in an evaporator
tube is done. The main objective of this paper is to find the length of the evaporator tube for a pre-defined
refrigerant inlet state such that the refrigerant at the tube outlet is superheated. The problem involves
refrigerant flowing inside a straight, horizontal copper tube over which water is in cross flow. Inlet
condition of the both fluids and evaporator tube detail except its length are specified. here pressure and
enthalpy at discrete points along the tube are calculated by using two-phase frictional pressure drop model.
Predicted values were compared using another different pressure drop model. A computer-code using
Turbo C has been developed for performing the entire calculation
THE EFFECT OF GEOMETRICAL PARAMETERS ON HEAT TRANSFER AND HYDRO DYNAMICAL CHA...ijmech
Compact size and high heat transfer coefficient of helical coil heat exchangers causes them to have an
important role in various industrial applications. This paper investigate numerically on the influence of
different parameters such as coil radius, coil pitch and diameter of tube on the hydrodynamic and
heat transfer characteristics of helical double tube heat exchangers using the CFD software which is
based on the principles of heat transfer, fluid mechanics and thermodynamics. The results indicated that
heat transfer augmentation occurs by increasing of the inner Dean Number, inner tube diameter, curvature
ratio and by the reduction of the pitch of heat exchanger coil. By increasing the radius of coils, the
secondary flow effects due to centrifugal forces diminishes and flow of fluid through the coils tends to flow
in a straight path and as a result, the friction coefficient decreases consequently.
An Experimenatl Study on Heat Transfer Behaviors of A Welded - Aluminum Minic...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
EFFECT OF DAM LOCATION ON THE PERFORMANCE CHARACTERISTICS OF TWO -LOBE BEARIN...ijmech
This paper presents the effect of pressure dam parameters on the static and dynamic characteristics of two
lobe pressure dam bearing. The modified Reynolds equation is derived on the basis of micropolar fluid
theory. The Galerkin approach of finite element method has been used to solve modified Reynold’s
equation for carrying out the performance characteristics. The characteristics, which have been calculated
for a wide range of dam parameters, have been found to be greatly influenced with the variation of the
micropolar parameters. Effect of various dam locations is presented on two micropolar parameter,
coupling number (N2) which couples the linear and angular momentum equation, arising the micro
rotational effect of the suspended particles in the fluid and characteristics length (lm) which represents the
interaction between the micropolar fluid and the film gap.
Effect of cylindrical texture on dynamic characteristics of journal bearingijmech
Effect of cylindrical texture on dynamic characteristics of hydrodynamic journal bearing is presented in this paper. The Reynolds equation is discretized by finite difference method and solved numerically in an iterative scheme satisfying the appropriate boundary conditions. Stiffness and damping coefficients of fluid film and stability parameters are found using the first-order perturbation method for different eccentricity ratios and various texture parameters like texture depth and texture portion. From the present study, it has found that cylindrical texture exhibits better stability than plain journal bearing.
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.
Numerical Analysis of Heat Transfer Enhancement in Pipe-inPipe Helical Coiled...iosrjce
These paper focuses on the effect of the inside tubes at constant value of mass flow rate and variation
of annulus mass flow rate on effect of Dean Number and overall heat transfer coefficient with constant wall
temperature, CFD analysis of a helically coiled heat exchanger. Also deals with the effect of Dean Number with
respect to Reynolds Number and Nusselt Number and Overall Heat Transfer coefficient on change of coil
configuration of helically coiled tube. The particular difference in this study in comparison with the other
similar studies was the boundary conditions for the helical coils. The results indicate that with the decrease the
inner coil diameter, the overall heat transfer coefficient is increased
Thermal analysis of various duct cross sections using altair hyperworks softwaresushil Choudhary
In this work thermal analysis and comparison of various duct cross sections is done computationally using Altair
Hyperworks Software. Simple Analytical results were obtained for conduction and convection through the ducts
which can be used to build up thermal circuit. The inner surface of all ducts is maintained at constant
temperature and ambient air is at certain temperature that is less than inner surface temperature of pipe. Due to
temperature difference heat will flow from higher temperature to lower temperature. Due to temperature
difference heat will flow from higher temperature to lower temperature. The material of pipe provides
conductive resistance and air provides convective resistance. Hence this is a mix mode of heat transfer. The heat
transfer takes place in one dimension only and properties are considered to be isotropic. The ducts are assumed
to be made of aluminium having known thermal conductivity and density. The surroundings of ducts have
known convective heat transfer coefficient and temperature. The results are obtained on hyperview which are for
heat flux, temperature gradient and grid temperature. The different characteristics can be obtained by varying the
material of the ducts.
Heat Transfer Analysis of Refrigerant Flow in an Evaporator TubeIJMER
the paper aim is to presenting the heat transfer analysis of refrigerant flow in an evaporator
tube is done. The main objective of this paper is to find the length of the evaporator tube for a pre-defined
refrigerant inlet state such that the refrigerant at the tube outlet is superheated. The problem involves
refrigerant flowing inside a straight, horizontal copper tube over which water is in cross flow. Inlet
condition of the both fluids and evaporator tube detail except its length are specified. here pressure and
enthalpy at discrete points along the tube are calculated by using two-phase frictional pressure drop model.
Predicted values were compared using another different pressure drop model. A computer-code using
Turbo C has been developed for performing the entire calculation
THE EFFECT OF GEOMETRICAL PARAMETERS ON HEAT TRANSFER AND HYDRO DYNAMICAL CHA...ijmech
Compact size and high heat transfer coefficient of helical coil heat exchangers causes them to have an
important role in various industrial applications. This paper investigate numerically on the influence of
different parameters such as coil radius, coil pitch and diameter of tube on the hydrodynamic and
heat transfer characteristics of helical double tube heat exchangers using the CFD software which is
based on the principles of heat transfer, fluid mechanics and thermodynamics. The results indicated that
heat transfer augmentation occurs by increasing of the inner Dean Number, inner tube diameter, curvature
ratio and by the reduction of the pitch of heat exchanger coil. By increasing the radius of coils, the
secondary flow effects due to centrifugal forces diminishes and flow of fluid through the coils tends to flow
in a straight path and as a result, the friction coefficient decreases consequently.
An Experimenatl Study on Heat Transfer Behaviors of A Welded - Aluminum Minic...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
EFFECT OF DAM LOCATION ON THE PERFORMANCE CHARACTERISTICS OF TWO -LOBE BEARIN...ijmech
This paper presents the effect of pressure dam parameters on the static and dynamic characteristics of two
lobe pressure dam bearing. The modified Reynolds equation is derived on the basis of micropolar fluid
theory. The Galerkin approach of finite element method has been used to solve modified Reynold’s
equation for carrying out the performance characteristics. The characteristics, which have been calculated
for a wide range of dam parameters, have been found to be greatly influenced with the variation of the
micropolar parameters. Effect of various dam locations is presented on two micropolar parameter,
coupling number (N2) which couples the linear and angular momentum equation, arising the micro
rotational effect of the suspended particles in the fluid and characteristics length (lm) which represents the
interaction between the micropolar fluid and the film gap.
Effect of cylindrical texture on dynamic characteristics of journal bearingijmech
Effect of cylindrical texture on dynamic characteristics of hydrodynamic journal bearing is presented in this paper. The Reynolds equation is discretized by finite difference method and solved numerically in an iterative scheme satisfying the appropriate boundary conditions. Stiffness and damping coefficients of fluid film and stability parameters are found using the first-order perturbation method for different eccentricity ratios and various texture parameters like texture depth and texture portion. From the present study, it has found that cylindrical texture exhibits better stability than plain journal bearing.
Structural dynamic analysis of bio inspired carbon polyethylene MAV wingsijmech
Flapping wing micro air vehicles (FWMAVs) are small unmanned aircrafts or flying robots which are intended to be used for surveillance, reconnaissance, biochemical sensing, targeting, tracking, etc. To perform such missions, MAVs are required to do some specific operations such as hovering; slow and high speed flying; quick landing and take-off, etc. During flapping motion through surrounding air, wings experience inertial and aerodynamic forces. For making successful flights in such conditions, wings must have properties such as flexibility, strength, low weight, long fatigue life, etc. For producing such properties, wing material plays a crucial
role. Most of the research related to MAVs is based on aerodynamics and controls. Present research is based on materials and structural aspects of flapping wings. Here materials used are carbon fibres for making wing skeleton and polyethylene for wing membrane. The design for
the wing of 113.8 mm length is inspired from giant hummingbird’s wing. The wing sketch was developed in gambit software by taking position data, generated using digitizer, from printed image of hummingbird wing. Developed sketch was printed and used, as a guide, for making the wing skeleton. The polyethylene film with adhesive was laminated on the skeleton at 150 ºC.
Natural frequencies, nature of mode shapes, and damping characteristics of fabricated wings are determined here
EXPERIMENTAL STUDIES ON THE INTAKE PORT OF A DIESEL ENGINE TO DETERMINE SWIRLijmech
This paper focuses on experimentalstudies of intake port of a four cylinder diesel engine for different
vacuum pressures and valve lift positions. In this study, the cylinder head is experimented through a paddle
wheel flow setup, which gives the flow coefficient and swirl number asoutput. Main scope of the work is to
understand the flow behaviour through the intake port and finally to determine mean flow coefficient and
mean swirl number for different valve lift ratios L/D, where L is valve lift and D is bore diameter.
EXPERIMENTAL ANALYSIS AND MODELLING OF GRINDING AISI D3 STEELijmech
Grinding of hardened steels for the realisation of better surface quality of the workpiece is an essentiality
of high productivity environments. The surface grinding of high carbon high chromium steels like AISI D3
with a production level grinding wheel used in the industry is the driver of the present research article. The
experimentation is done in dry as well as pool cooling conditions to ascertain the better of the two
conditions in providing a better set of cutting forces and surface finish. A mathematical model for
evaluating the forces generated during grinding is evolved and on comparison of the results obtained from
the model with the ones from experimentation is found to be correlating. The usage of production level
vitrified grinding wheel has shown good results in terms of lower forces generated and good surface finish
during surface grinding. The results are optimised and the set of inputs which yield good surface finish and
low forces are given. Dry grinding of AISI D13 yields good surface finish than wet grinding. Surface finish
of 0.14 microns is achievable using dry grinding.
OPTIMIZATION OF A TURBINE USED IN COAL FIRED THERMAL POWER PLANTS BASED ON IN...ijmech
The purpose of current study is to analyze the effect of inlet steam temperature coming from the boiler on
thermoeconomic performance of a steam turbine used in a coal fired thermal power plant. Second law of
thermodynamics is used to develop the thermoeconomic model for the turbine. Analyses based on exergetic
and exergoeconomic criteria are done for the turbine used in a 210 MW power plant. Methodology is
explained with the help of an example. Effect of inlet steam temperature on the exergetic efficiency of the
turbine, unit product cost of turbine and unit product boiler has been shown. Optimization has been done
for the turbine as a trade off between the unit product cost of inlet steam from the boiler and unit product
cost of the turbine.
AN ERGONOMIC APPROACH TO DESIGN HAND BLOCK TOOL FOR TEXTILE PRINTING HANDICRA...ijmech
Hand block textile printing is an important operation in small scale textile industries of India. Hand tool
mechanisms designed to reduce the various risk factors have rarely been studied. To make comfortable
handle design, musculoskeletal disorders prevalence investigation of workers associated with hand block
printing operation has been done. Data related to musculoskeletal discomfort were collected from 80
workers (age group 18-60 years) using questionnaire. Rapid upper limb assessment (RULA) technique was
applied for postural analysis. New hand block tool was designed using Autodesk Inventor 2014
(Educational Institute Version i.e. V5R12) and then analyzed with HyperMesh (Version 12.0) software.
Most of the workers reported that working with existing hand block tool is not comfortable. RULA
technique resulted as final score of arm and wrist for the working with existing hand block tool was found
out to be 5. After the modifications in hand block tool by using the ergonomics principles and
anthropometric data, RULA final score of arm and wrists for the working with developed hand block tool
was found out to be 3. The developed hand block tool has been revealed to be better than the existing one in
term of comfort level, it is improved 42.69% and production rate 29.62% increase as compared to the
existing hand block tool, it could offer an improved working facility and trim down unwanted workplace
injuries.
Yleiskatsaus yhteisömanagerin tehtäviin. Mitä tekee yhteisömanageri, entä sisältömanageri? Yhteisön määritelmä. Tarpeet. Motivaatio. Tavoitteellisuus. Mittarit. Yhteisöjen johtaminen. Millainen on hyvä yhteisömanageri. Yhteisömanageroinnin tulevaisuus.
Experimental Investigation of Vertical Downward Flow Boiling Heat Transfer i...IJMER
The present work is carried to determine the two phase heat transfer coefficient during flowing
vertical downward in the minichannel. The minichannel test section is made up of aluminum having
hydraulic diameter 1.33mm. The experiments were carried out by varying mass flow rate from 0.1g/sec to
0.3g/sec of steam at three different vapour qualities of 0.2, 0.4 and 0.6. The result showed as the heat flux
increases there is an increase in two phase heat transfer coefficient upto 20000W/m2 0C. In addition to
that there is a decrease in treand of heat transfer coefficient for vapour quality.
DESIGN OF STACKED MICROCHANNEL HEAT SINKS USING COMPUTATIONAL FLUID DYNAMICP singh
The heat extraction problem is becoming an important factor in the development of micro-electronics. Over the last decade, micromachining technology has been increasingly used for the development of highly efficient cooling devices called heat sink because of its undeniable advantages such as less coolant demands and small dimensions. One of the most important micromachining technologies is micro channels. Hence, the study of fluid flow and heat transfer in micro channels which are two essential parts of such devices, have attracted more attentions with broad applications in both engineering and medical problems. Heat sinks are classified into single-phase or two-phase according to whether boiling of liquid occurs inside the micro channels
The microchannel heat sink is designed for electronic chips that could be effectively cooled by means of forced convection, by water flowing through the microchannels. This project presents a Computational Fluid Dynamics (CFD) flow simulation modeling, where water is made to flow across different cross-sectional microchannel heat sinks placed on heat source. The flow simulation of water and convective heat transfer are carried by using commercial software “Solid Works Flow Simulation”. In the CFD process stacked microchannels of various cross-sections viz., rectangular, triangular, pentagonal and circular are designed, then by defining the computational domain, boundary conditions as inlet mass flow (1e-5 kg/s),outlet pressure ( static pressure) and heat flux(750w/cm2) and by considering the parallel and counter flow direction of water in different cross-sectional microchannels the temperature drop in heat sink, pressure drop across the channels and amount of volumetric heat transfer coefficient are analyzed and compared.
Thermal and fluid characteristics of three-layer microchannels heat sinksjournal ijrtem
ABSTRACT : A heat sink with three layers of microchannels with different flow arrangements has been studied numerically using CFD fluent software version 15. The different flow arrangements using uniform and divergence channels on thermal characteristics of heat sinks at the same mass flow rate are investigated. The results indicated that, uniform channels with counter-flow 1 arrangement provide the best temperature uniformity and divergence channels with counter flow gives the best heat sink performance.
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.
Experiment on single-mode feedback control of oscillatory thermocapillary con...IJERA Editor
Feedback control was carried out on nonlinear thermocapillary convections in a half-zone liquid bridge of a high
Prandtl number fluid under normal gravity. In the liquid bridge, the convection changed from a two-dimensional
steady flow to a three-dimensional oscillatory flow at a critical temperature difference. Feedback control was
realized by locally modifying the free surface temperature using local temperature measured at different
positions. The present study aims to confirm whether the control method can effectively suppress oscillatory
flows with every modal structure. Consequently, the control was theoretically verified to be effective for
oscillatory flows with every modal structure in a high Marangoni number range.
Research Inventy : International Journal of Engineering and Scienceinventy
Research Inventy : International Journal of Engineering and Science
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
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.
Esign and thermal evaluation of shell and helical coil heat exchangereSAT Journals
Abstract
Heat exchangers are the important engineering equipments used for transferring heat from one fluid to another. Heat exchangers are widely used in various kinds of application such as power plants, nuclear reactors, refrigeration and air-conditioning systems, heat recovery systems, petrochemical, mechanical, biomedical industries. Helical coil heat exchangers are gaining wide importance now-a-days because it can give high heat transfer coefficient in small footprint of surface area. This paper focuses on the designing of shell and helical coil heat exchanger and its thermal evaluation with counter flow configuration. The thermal analysis is carried out considering the various parameters such as flow rate of cold water, flow rate of hot water, temperature, effectiveness and overall heat transfer coefficient.
Keywords— Helical coil heat exchanger, Counter flow, Flow rate, effectiveness, heat transfer coefficient etc.
Design and Experimental Analysis of Rectangular Wavy Micro Channel Heat sinkAM Publications
An experimental investigation has been explore in order to study the flow of fluid and heat transfer characteristics on a Rectangular Wavy microchannel heat sink. Various applications are envisaged for the use of microchannel heat sink in electrical and electronic power generation and distribution. The Heat sink with microchannel is designed on an Aluminium specimen with Rectangular Wavy configuration with a channel cross section of 1mm x 0.5mm.To improve the heat transfer performance of the cooling system is achieved by using nanoparticles in the fluid passing through the microchannel heat sink. Results are presented by using different concentration (with 1% to 3%) of Nano fluids in water for the heat sink. Various cooling characteristics including thermal resistance, temperature drop and pressure drop across the microchannel heat sink are analysed for different volume concentrations, different volumetric flow rates and Reynolds number. Other significant characteristics for the measurement of heat transfer characteristics across this microchannel heat sink are also analysed and presented in this experiment.
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EXPERIMENTAL ANALYSIS OF HEAT TRANSFER AND FLUID FLOW IN MICRO-CHANNEL HEAT SINK
1. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.5, No.3, August 2016
DOI: 10.14810/ijmech.2016.5302 13
EXPERIMENTAL ANALYSIS OF HEAT TRANSFER
AND FLUID FLOW IN MICRO-CHANNEL HEAT SINK
Rajesh Sharma, Amoljit Singh Gill and Vikas Dhawan
Mechanical Engineering Department, Cec, Landran
ABSTRACT
In this paper heat transfer in single phase through micro-channels was studied. The validation of classical
correlations of conventional channels to micro-channels is explored. It is found that classical approach is
in good agreement with the experimental results of heat transfer in micro-channels .The material used for
micro-channel heat sink (MCHS) is copper, experiments were conducted using water as cooling agent in
this study. Micro-channels are made with the help of EDM machine on the upper surface of MCHS.
Variation of heat transfer rates, effect of friction factor, effect of pressure drop and variation in
temperature distribution is investigated in this study. It is observed in the study that with decrease in
velocity flow friction also decreases.
KEYWORDS
micro-channel; electronics cooling; friction factor
1. INTRODUCTION
Micro-channel heat exchangers are extensively used in various applications and industries for
saving energy and resources. Investigation of micro-channels is based on the single phase internal
flow correlation for convective heat transfer:
u
h
k
h N
D
= (1)
Nusselt number remains a constant for internal flow. Above mentioned correlation is investigated
by Tuckerman and pease [1]. Their results encouraged and motivated others to investigate heat
transfer in micro-channels. Due to miniaturizations of the electronic components and due to space
considerations and demand for high speeds, the cooling of electronic components has become a
tough challenge. So we need compact heat exchangers which can cool these components at faster
rates and may be small in their size so, micro channel type compact heat exchangers offer
advantages due to higher heat transfer coefficients. The large surface to volume ratios helps in
enhanced heat transfer rates in micro-channels.
Micro-channels are the heat sinks which can transfer large amount of heat and can be fabricated
by different techniques [2]. Micro-channels were used first time by Tuckerman and Pease [1]
.They used water as a coolant under laminar conditions through micro-channels. They used
micro-channels for electronics cooling and able to achieve heat fluxes as high as 790 W/cm2
with
the chip temperature maintained below 110ºC. Various other authors investigated heat transfer in
micro-channels [3-7].
X.F. Peng et al. [8] concluded that for flow in micro-channels, the low values of the inner
diameter limit the significance of the mixed convection. Chein-Yuh Yang et. al.[9] investigated
that at lower values of Re (Reynolds No.) the temperature variation increases along length and
2. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.5, No.3, August 2016
14
heat losses are higher in the downstream. As the value of Re increases thermal resistance and
friction factor decreases but pressure drop, heat transfer coefficient and pumping power increases
[10].
Surface roughness plays an important role in the micro-channel performances [11], since at micro
level it is nearly impossible to obtain smooth surface. Large roughness of the micro-channel
causes high friction factor [12-13]. The convective heat transfer rate can be enhanced by varying
boundary conditions, geometry, or by enhancement of thermal conductivity of the fluid [14].
Nowadays nano particles are used for the enhancement of heat transfer rates but they also rises
presuree drop [15-19].
The controlling factors for the enhanced heat transfer in micro-channels are velocity of working
fluid ,type of heat transfer i.e. single phase or vapor phase, type of material used for heat
exchanger ,pressure drop and friction factor.
In present study investigations are made on the above mentioned factors and presented in the
form of figures or graphs. It is observed that the conventional heat transfer relations and equations
are also applicable to microchannels. Various literatures [1, 20-23] also validate the same.
2. EXPERIMENTAL SETUP AND PROCEDURES
Water as a working or cooling fluid is taken from a reservoir with the help of a pump, which
provides steady and smooth flow over wide range of flow rates. Flow rate from 0.3 L/min. to 3.5
L/min are used in this investigation. The fluid enters into the copper micro-channel test section
through inlet plenum. The fluid takes the heat from the micro-channel test section, which is
heated by using cartilage heating system. Hot fluid then exits from the test section and passes
through the heat exchanger which is used for lowering the temperature of working fluid i.e. water.
After that working fluid goes to reservoir. Closed loop cooling system is used in the experimental
set-up.
The equivalent hydraulic diameter was calculated using the following expression:
4hD A P= (2)
Figure 1 Flow Diagram Experimental Setup
3. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.5, No.3, August 2016
15
Thermocouples were used to measure the temperatures of micro-channel walls (shown in Figure
2). Data acquisition system as shown in Figure 3 is used to read the temperatures and provides
temperature distribution across the length of micro-channels. Heat gain by the coolant is provided
by the following equation:
, ,( )p m o m iq c Q T Tρ= − (3)
where Q is volumetric flow rate, , ,( )m o m iT andT inlet and outlet fluid temperatures.
The actual picture of micro-channel heat sink is shown in Figure 4.The heat transfer coefficient is
determined from the following relation:
/[ ( )]w mh q NA T T= − (4)
The desired flow rates are obtained with the help of needle valve used in the circuit. After the
stabilization of flow, heat is supplied to the MCHS through cartridge heaters provided in the
bottom of MCHS. The temperature measurements from all the sensors were stored using data
acquisition system during the experimentations. Following correlations given in Table1 are used
for investigations.
Figure 2 Position of Thermocouples in Micro Channel
Figure 3 Data Acquisition System Heat Sink
4. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.5, No.3, August 2016
16
3. RESULTS AND DISCUSSION
The heat transfer correlations used for laminar flows in channels are shown in Table 1 these
correlations have been widely used in the literature for comparison against experimental results
for micro-channels. The correlations presented in the table are according to different flow and
boundary conditions.
Figure 4 Actual Microchannel Heat Sink with Adapters
Table 1 Convection Correlations for Flow in a Micro Channel Heat Sink
conditions Correlations
Laminar fully developed 64
Re
Laminar fully developed, uniform
heat flux
Pr ≥ 0.6
36.4=Nu
Laminar fully developed, uniform
Ts,
Pr ≥ 0.6
66.3=Nu
Laminar, thermal entry length,
uniform Ts 3/2
Pr]Re)/[(04.01
PrRe)/(0668.0
66.3
LD
LD
Nu
+
+=
The changes in pressure drop with respect to velocity i.e. Reynolds no. is shown in Figure 5. It
was observed that with increase in velocity the pressure drop also increases.But it is also observed
that effect of heat flux on pressure drop is negligible.
5. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.5, No.3, August 2016
17
Figure 5 Reynolds Number Versus Pressure Drop at Different Heat Fluxes
The variation of experimental fanning friction factor with Reynolds number varying from 350 to
2200 is shown in Figure 6 for micro-channels having hydraulic diameter 0.61 mm and depth 2.5
mm. It was observed that fanning friction decreases up to certain limit with increases in Reynolds
no. and after that it decreases. The shape of the graph was observed as ‘S’ in shape.
Figure 6 Reynolds Number Versus Fanning Friction Factor .
It has been from the Figure 7 that there is negligible effect of heat flux on fanning friction. As
seen form figure that the fanning friction line remains straight with variation in heat flux values.
0
1
2
3
4
5
6
0 500 1000 1500 2000dP(Kpa)
Re
Heat flux
17.77
w/cm²
Heat flux
35.55
w/cm²
9.8
10
10.2
10.4
10.6
10.8
11
11.2
11.4
11.6
0 1000 2000
f.re
Re
Heat
flux
17.77
w/cm²
6. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.5, No.3, August 2016
18
Figure 7 Heat Flux Verses Fanning Friction at Different Reynolds Numbers
It was observed that with increase in mass flow rate, the heat transfer rate also increases, which is
given by the relation
pq mc T′′ = ∆
(8)
So with large mass flow rates rise in temperature of micro-channel walls becomes low i.e. cooling
will be better.
Same trends were observed for other heat fluxes, as shown in Figures 8 (a),(b), (c) and (d).As
flow rate was increased from 0.5 LPM to 2.5 LPM, it was observed that the heat removal rate also
increases rapidly.It is also seen from the figure that with increases in flow rate of microchannels
will be able to resist the increase in temperature.
(a) (b)
7. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.5, No.3, August 2016
19
(c) (d)
(e)
Figure 8 Temperature distributions along the length of micro channel heat sink (MCHS) in non-
dimensional form at different flow rates (a)17.77 W/cm2
,(b)35.55 W/cm2
, (c)53.33 W/cm2
, (d)71.11
W/cm2
and (e) 88.88 W/cm2
5. CONCLUSION
Experimental analysis was made for the fluid flow and heat transfer with micro-channels.The
conclusions made throughout the study are discussed in this section.When mass flow rate
decreases, friction factor also decreases due to decrease in velocity of flowing fluid. The pressure
drop increases with increase in velocity of fluid, thereby increases heat flux removal rate. Initially
fanning friction factor decreases as there is increase in mass flow rate. But after certain value of
mass flow rate it starts increasing. The heat transfer rate from MCHS increases with increase in
mass flow rate. And in turn pressure loss is converted into heat which is carried by the water
which was used as cooling agent.So it is observed that conventional mathematical correlations or
equations used for conventional channels can be used for micro-channels.
8. International Journal of Recent advances in Mechanical Engineering (IJMECH) Vol.5, No.3, August 2016
20
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