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Exercise
Problem Statement
Consider a pair of concentric cylinders with a height of 24 mm. The smaller cylinder has a radius of 12 mm. The inner and outer radius of the larger, hollow cylinder is 24 mm and 25 mm, respectively. The same boundary condition and the initial condition from the shell and specimen tutorial will be used: Convection on the outer surface of the larger, hollow cylinder, and two different radiation boundary condition for each emitting surface. The larger, hollow cylinder will be set to 22 degress Celsius and the smaller cylinder will be set to -273.15 degrees Celsius.
Analytic Solution
Assume only the inner surface of the larger, hollow cylinder and the cylindrical surface of the smaller cylinder are emitting radiation. Also assume the surfaces are gray and diffuse. The net radiation of this two-surface enclosure is give below:
In this convention, the subscript "1" denotes the smaller cylinder and the subscript "2" denotes the larger, hollow cylinder. Hence, the above equation is the net radiation of the smaller cylinder.
The analytic solution shows the net radiation of the smaller cylinder is -0.428 watts.
ANSYS result
Solve this problem with the same procedure for the shell and specimen tutorial. First solve the steady state model and transfer the data to transient analysis to complete the simulation.