Exterior Shape Factors From Interior Shape Factors

Shape factors for steady heat conduction enable quick and highly simplified calculations of heat transfer rates within bodies having a combination of isothermal and adiabatic boundary conditions. Many shape factors have been tabulated, and most undergraduate heat transfer books cover their derivatio...

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Main Author: Lienhard, John H
Other Authors: Massachusetts Institute of Technology. Department of Mechanical Engineering
Format: Article
Language:en_US
Published: ASME International 2019
Online Access:https://hdl.handle.net/1721.1/121994
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author Lienhard, John H
author2 Massachusetts Institute of Technology. Department of Mechanical Engineering
author_facet Massachusetts Institute of Technology. Department of Mechanical Engineering
Lienhard, John H
author_sort Lienhard, John H
collection MIT
description Shape factors for steady heat conduction enable quick and highly simplified calculations of heat transfer rates within bodies having a combination of isothermal and adiabatic boundary conditions. Many shape factors have been tabulated, and most undergraduate heat transfer books cover their derivation and use. However, the analytical determination of shape factors for any but the simplest configurations can quickly come to involve complicated mathematics, and, for that reason, it is desirable to extend the available results as far as possible. In this paper, we show that known shape factors for the interior of two-dimensional objects are identical to the corresponding shape factors for the exterior of those objects. The canonical case of the interior and exterior of a disk is examined first. Then, conformal mapping is used to relate known configurations for squares and rectangles to the solutions for the disk. Both a geometrical and a mathematical argument are introduced to show that shape factors are invariant under conformal mapping. Finally, the general case is demonstrated using Green's functions. In addition, the “Yin-Yang” phenomenon for conduction shape factors is explained as a rotation of the unit disk prior to conformal mapping.
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spelling mit-1721.1/1219942022-09-28T08:29:46Z Exterior Shape Factors From Interior Shape Factors Lienhard, John H Massachusetts Institute of Technology. Department of Mechanical Engineering Massachusetts Institute of Technology. Robust Design Group Shape factors for steady heat conduction enable quick and highly simplified calculations of heat transfer rates within bodies having a combination of isothermal and adiabatic boundary conditions. Many shape factors have been tabulated, and most undergraduate heat transfer books cover their derivation and use. However, the analytical determination of shape factors for any but the simplest configurations can quickly come to involve complicated mathematics, and, for that reason, it is desirable to extend the available results as far as possible. In this paper, we show that known shape factors for the interior of two-dimensional objects are identical to the corresponding shape factors for the exterior of those objects. The canonical case of the interior and exterior of a disk is examined first. Then, conformal mapping is used to relate known configurations for squares and rectangles to the solutions for the disk. Both a geometrical and a mathematical argument are introduced to show that shape factors are invariant under conformal mapping. Finally, the general case is demonstrated using Green's functions. In addition, the “Yin-Yang” phenomenon for conduction shape factors is explained as a rotation of the unit disk prior to conformal mapping. 2019-08-16T14:02:10Z 2019-08-16T14:02:10Z 2019-04 2019-01 Article http://purl.org/eprint/type/JournalArticle 0022-1481 https://hdl.handle.net/1721.1/121994 Lienhard, John H., V. et al. "Exterior Shape Factors From Interior Shape Factors." Journal of Heat Transfer 141, 6 (April 2019): 061301 © 2019 American Society of Mechanical Engineers en_US http://dx.doi.org/10.1115/1.4042912 Exterior Shape Factors From Interior Shape Factors Creative Commons Attribution 4.0 International license https://creativecommons.org/licenses/by/4.0/ application/pdf ASME International ASME
spellingShingle Lienhard, John H
Exterior Shape Factors From Interior Shape Factors
title Exterior Shape Factors From Interior Shape Factors
title_full Exterior Shape Factors From Interior Shape Factors
title_fullStr Exterior Shape Factors From Interior Shape Factors
title_full_unstemmed Exterior Shape Factors From Interior Shape Factors
title_short Exterior Shape Factors From Interior Shape Factors
title_sort exterior shape factors from interior shape factors
url https://hdl.handle.net/1721.1/121994
work_keys_str_mv AT lienhardjohnh exteriorshapefactorsfrominteriorshapefactors