{"id":158807,"date":"2021-05-24T16:14:17","date_gmt":"2021-05-24T16:14:17","guid":{"rendered":"\/forum\/forums\/topic\/radiative-heat-flux\/"},"modified":"2022-04-21T14:15:14","modified_gmt":"2022-04-21T14:15:14","slug":"radiative-heat-flux","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/radiative-heat-flux\/","title":{"rendered":"Radiative Heat Flux"},"content":{"rendered":"
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I am new to modeling radiative heat transfer using Ansys\/Fluent. Any pointers to model the following problem will be greatly appreciated.<\/p>\n

The computational domain is cylindrical cavity with 0.5 m radius and 3 m long, and the boundary surfaces are black surfaces at 300K. The medium is a participating medium with an absorption coefficient of 0.1 m^-1 (gray gas) and temperature 1200K. In this problem, I would like to calculate the radiative heat flux to the cylindrical surface.<\/p>\n

Here is the setup that I used.<\/p>\n

Radiation Model: Discrete Ordinate (DO) method with 4 divisions along theta and phi directions and number of bands as zero (gray gas).<\/p>\n

Material models: Absorption coefficient as 0.1 m^-1 and scattering coefficient as 0.0 m^-1.<\/p>\n

Cell Zone Conditions: Set as Participates in Radiation<\/p>\n

Boundary Condition: For “Thermal” condition, selected “Radiation” and set “External Emissivity” as 1.0, and “External Radiation Temperature” as 300K. For “Radiation”, set the BC Type as opaque, and “Internal Emissivity” as 1.0 and “Diffusion Fraction” as 0.0<\/p>\n

I tried two different options.<\/p>\n

·        In the first case, flow, energy, and DO equations are solved. In this case, as expected, the temperature became uniform at the end of the iterations and radiative heat flux became a very small value. <\/p>\n

·        In the second case, I solved only DO equation (turned off the flow and energy equations under Solution -> Control -> Equations), since I wanted to calculate the radiative heat flux when the temperature inside the cavity is 1200K and wall temperature is 300K. DO method converged in a few iterations. However, the radiative heat flux at the wall is showing as zero. I guess, this is because the energy equation is not solved. Is there any way I can calculate the radiative heat flux, after DO method converges? <\/p>\n

Attached is an image of the heat flux distribution for this case from a published paper.<\/p>\n

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\n\"HeatFlux.PNG\"
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