VM227

VM227
Radiation Between Finite Coaxial Cylinders

Overview

Reference:	M. Modest, Radiative Heat Transfer, McGraw-Hill Book Co., Inc., New York, NY, 1992, p. 791, View Factor Evaluations 44, 45.
Analysis Type(s):	Steady State Radiosity
Element Type(s):	2D 8-Node Thermal Solid Elements (PLANE77)
Input Listing:	vm227.dat

Test Case

This test is designed to show a quick calculation of the end effects which are present in the radiation solution of two finite concentric cylinders. Concentric cylinders of length L, with radii r₁ and r₂, are created, and the radiosity method is used to determine radiation view factors upon the facing surfaces.

Figure 377: Problem sketch of finite co-axial cylinder

Figure 378: Problem Sketch

Geometric Properties

l = 10

r₁ = 1

r₂ = 3

Interior surface of external cylinder ε = 1

Axial surface of internal cylinder ε = 1

All other surfaces ε = 0

Analysis Assumptions and Modeling Notes

The model is reduced to a 2D axisymmetric case. The material is assumed to be isotropic, the surface is assumed to have uniform emissivity.

A = 108

B = 92

Results

	Target	Mechanical APDL	Ratio
VF (1-1)	0.000	0.000	0.000
VF (2-1)	0.288	0.288	1.000
VF (2-2)	0.503	0.480	0.950