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

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.

2016 ◽  
Vol 10 (8) ◽  
pp. 12
Author(s):  
Hussein J. Akeiber ◽  
Mazlan A. Wahid ◽  
Hasanen M. Hussen ◽  
Abdulrahman Th. Mohammad ◽  
Bashar Mudhaffar Abdullah ◽  
...  

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.


1977 ◽  
Vol 42 (4) ◽  
pp. 571-577 ◽  
Author(s):  
R. T. Balmer ◽  
A. D. Strobusch

It is shown that for cylindrical and spherical bodies there is a critical radius below which the addition of any form of insulation to the body will increase rather than decrease the cooling of the body. It is proposed, therefore, that it would be thermally detrimental to newborn homeotherms to be born with a protective covering (fur or down) if their body size were less than this critical size, and consequently that the degree of natal covering is not necessarily related to the overall development of the species when the birth size is less than this critical size. A critical weight is derived from the critical radius for basically spherical animals which compares favorably with typical birth weights of various altricial homeotherms. The effect of the overall conductive-convective heat transfer caused by a basically cylindrical animal rolling up into a ball is also discussed.


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