Analytical modeling of temperature distribution in an anisotropic cylinder with circumferentially-varying convective heat transfer

2014 ◽  
Vol 79 ◽  
pp. 1027-1033 ◽  
Author(s):  
D. Sarkar ◽  
K. Shah ◽  
A. Haji-Sheikh ◽  
A. Jain
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Analytical Modeling ◽  
Anisotropic Cylinder

scholarly journals Prediction of Convective Heat Transfer Coefficient and Temperature Distribution of Air-Conditioned Spaces Using Numerical Simulation

2016 ◽  
Vol 10 (8) ◽  
pp. 12
Author(s):  
Hussein J. Akeiber ◽  
Mazlan A. Wahid ◽  
Hasanen M. Hussen ◽  
Abdulrahman Th. Mohammad ◽  
Bashar Mudhaffar Abdullah ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Transfer Coefficient ◽  
Temperature Distribution ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Convective Heat Transfer Coefficient ◽  
Solution Technique ◽  
Geometrical Parameters

Accurate and efficient modeling of convective heat transfer coefficient (CHTC) by considering the detailed room geometry and heat flux density in building is demanding for economy, environmental amiability, and user satisfaction. We report the three-dimensional finite-volume numerical simulation of internal room flow field characteristics with heated walls. Two different room geometries are chosen to determine the CHTC and temperature distribution. The conservation equations (elliptic partial differential) for the incompressible fluid flows are numerically solved using iterative method with no-slip boundary conditions to compute velocity components, pressure, temperature, turbulent kinetic energy, and dissipation rate. A line-by-line solution technique combined with a tri-diagonal matrix algorithm (TDMA) is used. The temperature field is simulated for various combinations of air-change per hour and geometrical parameters. The values of HTCs are found to enhance with increasing wall temperatures.

Heat transfer modeling within the microclimate between 3D human body and clothing: effects of ventilation openings and fire intensity

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Miao Tian ◽  
Jun Li
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Temperature Distribution ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Human Body ◽  
Thermal Environment ◽  
Heat Transfer Process ◽  
Fire Intensity ◽  
Content Type

PurposeThe purpose of this study is to determine the effect of ventilation openings and fire intensity on heat transfer and fluid flow within the microclimate between 3D human body and clothing.Design/methodology/approachOn account of interaction effects of fire and ventilation openings on heat transfer process, a 3D transient computational fluid dynamics model considering the real shape of human body and clothing was developed. The model was validated by comparing heat flux history and distribution with experimental results. Heat transfer modes and fluid flow were investigated under three levels of fire intensity for the microclimate with ventilation openings and closures.FindingsTemperature distribution on skin surface with open microclimate was heavily depended on the heat transfer through ventilation openings. Higher temperature for the clothing with confined microclimate was affected by the position and direction of flames injection. The presence of openings contributed to the greater velocity at forearms, shanks and around neck, which enhanced the convective heat transfer within microclimate. Thermal radiation was the dominant heat transfer mode within the microclimate for garment with closures. On the contrary, convective heat transfer within microclimate for clothing with openings cannot be neglected.Practical implicationsThe findings provided fundamental supports for the ease and pattern design of the improved thermal protective systems, so as to realize the optimal thermal insulation of the microclimate on the garment level in the future.Originality/valueThe outcomes broaden the insights of results obtained from the mesoscale models. Different high skin temperature distribution and heat transfer modes caused by thermal environment and clothing structure provide basis for advanced thermal protective clothing design.

Convective Heat Transfer Studies in Mini-Channels Using Digital Interferometry

2009 ◽  
Author(s):  
V. Sajith ◽  
Divya Haridas ◽  
C. B. Sobhan ◽  
G. R. C. Reddy
Keyword(s):  
Heat Transfer ◽  
Image Processing ◽  
Temperature Distribution ◽  
Convective Heat Transfer ◽  
Digital Image Processing ◽  
Convective Heat ◽  
Digital Image ◽  
Test Section ◽  
Average Heat ◽  
Mini Channels

Convective heat transfer in micro and mini channels has been recommended as an effective heat removal method for various electronic packages and systems. Experimental and theoretical investigations on the thermal performance of micro and mini channels have gained immense attention and hence, heat transfer studies in mini channels are of great importance. Some of the experimental results found in the literature on heat transfer in small-dimension channels are of contradicting nature even though some generally agreeing results are also found. One of the probable reasons for such deviations is the intrusive nature of the measurement techniques used. The traditional method of temperature measurement in channels uses the thermocouple probe, and for obtaining temperature distribution across the channel either a number of probes or a moving probe technique is required, both of which disturb the flow field and cause measurement errors. Hence a non intrusive measurement technique, such as an optical method is preferable for temperature measurement in small channels. In the present work, convective heat transfer studies have been performed on water flowing through a mini channel of hydraulic diameter 4 mm, using the non-intrusive technique of laser interferometry, coupled with digital image processing. The channel is fabricated using high quality optical glass and aluminum blocks. Mach Zehnder Interferometry is used for obtaining the temperature distribution in the channel. The experimental arrangement consists of two identical channels, one placed in the test section and the other in the reference section of the interferometric set up. As the test section is heated, a density variation is produced in the medium, which causes a refractive index variation, deforming interference fringes. This enables the calculation of the temperature distribution inside the channel. The interferograms are grabbed using a CCD camera and an AVT Fire package software. Digital image processing technique, using MATLAB software is used for locating the fringe-centers, and calculating the temperature distribution. The temperature profiles are obtained at different sections of the channel for various values of the average Reynolds number and various heating levels. The local and average heat flux values are obtained from the constructed temperature distributions. Variations of the local and average heat transfer coefficients and Nusselt number are determined and discussed. Results of parametric studies are compared and contrasted with relevant entry length solutions from the literature.

On the Convective Heat Transfer in a Tube of Elliptic Cross Section Maintained Under Constant Wall Temperature

1986 ◽  
Vol 108 (1) ◽  
pp. 33-39 ◽  
Author(s):  
M. A. Ebadian ◽  
H. C. Topakoglu ◽  
O. A. Arnas
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Temperature Distribution ◽  
Convective Heat Transfer ◽  
Cross Section ◽  
Convective Heat ◽  
Wall Temperature ◽  
Elliptic Cross Section ◽  
Constant Wall Temperature ◽  
Elliptic Cross

The convective heat transfer problem along the portion of a tube of elliptic cross section maintained under a constant wall temperature where hydrodynamically and thermally fully developed flow conditions prevail is solved in this paper. The successive approximation method is used for the solution utilizing elliptic coordinates. Analytical expressions for temperature distribution and Nusselt number corresponding to the first cycle of approximation are obtained in terms of the ellipticity of the cross section. In the case of a circular section, the first cycle approximation of the Nusselt number is obtained as 3.7288 compared to the exact value of 3.6568. Representative temperature distribution curves are plotted and compared to those corresponding with constant wall heat flux conditions.

Mechanism of Convective Heat Transfer of Airflow in Deep Airway

2011 ◽  
Vol 243-249 ◽  
pp. 4998-5002
Author(s):  
Yi Jiang Wang ◽  
Guo Qing Zhou ◽  
Lei Wu ◽  
Yong Lu
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Temperature Distribution ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Constant Heat Flux ◽  
Constant Heat ◽  
Mining Depth ◽  
Axial Temperature ◽  
Criterion Equation

With the increase of mining depth, an investigation of the convective heat transfer of airflow in deep airway is urgently required. The velocity and temperature distribution were derived by using the turbulence model for smooth tube. In order to simplify calculation and avoid the complicated calculation of integration, with the help of velocity-temperature distribution analogy, the criterion equation of convective heat transfer was obtained by using the model of constant heat flux. The coefficient of convective heat transfer between airflow and airway was calculated, and criterion correlation of convective heat transfer was regressed according to test data. Test results show that the axial temperature distribution of airflow is linear, which is encouraging agreement with theoretical calculating results. Hence model of constant heat flux is a viable method for studying the convective heat transfer of airflow in deep airway.

scholarly journals Heat Transfer Analysis and Performance Measurements of Hollow Pin-fin in Natural Convection

2019 ◽  
Vol 8 (6S) ◽  
pp. 727-731
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Temperature Distribution ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Thermal Performance ◽  
Temperature Drop ◽  
Heat Transfer Analysis ◽  
Pin Fin ◽  
And Performance

The Fin act as dissipiating elements, selection of proper geometry plays crusial role in increasing the rate of heat transfer and performance of the system. This work has been undertaken to investigate and compare thermal performance of solid and hollow pin-fin. Heat transfer analysis of solid and hollow pin fin carried and the results was compared with the experimental results. experiment was conducted to analyze the natural convection around solid hollow pin fin, and compare thermal performance of hollow pin fin with the solid pin fin of same dimension and orientation. The experimental result of temperature distribution shows that the faster temperature drop along the length. The high value of convective heat transfer in the initial phase due to which faster temperature drop takes place. Convection is found to be dominating due to less area for conduction along the length. Theoretical value and experimental value are close to each for temperature distribution as well the convective heat transfer coefficient. Efficiency is reduced in the case of hollow fin but the effectiveness of the hollow pin fin is increased by 1.76 times from an economical point of view, holoow pin fin is more efficient solution.

Analytical Solution for Temperature Distribution in a Multilayer Body With Spatially Varying Convective Heat Transfer Boundary Conditions on Both Ends

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Long Zhou ◽  
Mohammad Parhizi ◽  
Ankur Jain
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Boundary Conditions ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Thermal Conduction ◽  
The Body ◽  
Theoretical Understanding ◽  
Linear Algebraic Equations ◽  
Spatially Varying

Abstract Analytical modeling of thermal conduction in a multilayer body is of practical importance in several engineering applications such as microelectronics cooling, building insulation, and micro-electromechanical systems. A number of analytical methods have been used in past work to determine multilayer temperature distribution for various boundary conditions. However, there is a lack of work on solving the multilayer thermal conduction problem in the presence of spatially varying convective heat transfer boundary condition. This paper derives the steady-state temperature distribution in a multilayer body with spatially varying convective heat transfer coefficients on both ends of the body. Internal heat generation within each layer and thermal contact resistance between layers are both accounted for. The solution is presented in the form of an eigenfunction series, the coefficients of which are shown to be governed by a set of linear, algebraic equations that can be easily solved. Results are shown to be in good agreement with numerical simulation and with a standard solution for a special case. The model is used to analyze heat transfer for two specific problems of interest involving spatially varying convective heat transfer representative of jet impingement and laminar flow past a flat plate. In addition to enhancing the theoretical understanding of multilayer heat transfer, this work also contributes toward design and optimization of practical engineering systems comprising multilayer bodies.

scholarly journals EXPERIMENTAL INVESTIGATIONS OF CONVECTIVE HEAT TRANSFER OVER AN AIRFOIL SURFACE

2012 ◽  
pp. 232-237
Author(s):  
SAMPATH EMANI ◽  
SIDDHARDHA SEETALA ◽  
SIVAYAZI KAPPAGANTULA
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Measuring Transducer ◽  
Experimental Investigations ◽  
Heat Transfer Characteristics ◽  
Airfoil Surface ◽  
Drag And Lift ◽  
Lift And Drag

As experimentation becomes more complex, the need for the co-operation in it of technical elements from outside becomes greater and the modern laboratory tends increasingly to resemble the factory and to employ in its service increasing numbers of purely routine workers. This experimentation involves calculation of flow and Convective heat transfer characteristics of an airfoil. Firstly we are placing the airfoil in the wind tunnel having pressure distribution measurement equipment. There we are placing Digital 2 –component force measuring Transducer by which we are getting the lift and drag values acting on the airfoil .so from the above information we are going to calculate the coefficient of drag so that we can know design considerations so as to reduce the drag and lift force acting on the airfoil shaped bodies. Another parameter we are analyzing here is the temperature distribution at various points which requires an airfoil drilled at different points and counter sunken with respective screws for thermocouples insertion. Thermocouples are used to measure the reading of the temperature distribution at given points .Initially the reading is taken without any heat input to the airfoil specimen, after giving the heat energy externally we are going to determine the value of convective heat transfer from the airfoil element to the surroundings. So according to this we are going to temperature distribution of the airfoil.

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