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JoHn@ March 31, 2004 15:49

Solar Heat Flux
 
Hello all; How can i model the solar heat flux falling on a wall?I've tried to use heat flux boundary condition with a value say 100w/m2, however, results are totally unphysical, i got temperatures in the range of 600 to 700k. Is it the heat flux that i should modify?suggestions please. Thanks.

co2 March 31, 2004 21:58

Re: Solar Heat Flux
 
you will need to refer to a basic solar engineering book. modeling solar heat flux is not trivial. 100 W/m2 is not a bad guess for about 2 PM time period. But again this varies from place to place, time of year, cloud cover so on and so forth .. let me know what exactly you are looking to do with solar heat flux

JoHn April 1, 2004 08:02

Re: Solar Heat Flux
 
Okey. I have no problem with getting the values of the solar heat flux.The problem is the boundary condition i should use with my problem.I have a 25cm thick concrete wall.The use of a heat flux is giving me crazy temperature values, in the range of 600K inside the wall! This is surely unphysical...its like i am having an isolated system where i keep adding heat to it and the temperature rises infinitely...What BC should i use? Thanks.

co2 April 1, 2004 10:53

Re: Solar Heat Flux
 
you will need to write a UDF to release equivalent amount of heat in your wall.

heatflux (W/m2) * area of cell exposed / cell volume.

that will give u good results


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