Learning Forum

[Ahmad Alqatamin]

hello,
If I apply solar radiation to a surface by setting a constant value to heat flux 1000 w/m2 on the boundary conditions, it is the same result? when I apply the radiation model and put direct solar irradiance 1000w/m2 when assuming diffuse irradiation neglected

[Mark Owens]

Hi, no, it will only be similar if the absorbtion coefficeint in the fluid is very large. If you set a wall heat flux of 1000 W/m^2 (in the thermal tab) the heat will go into the fluid cell next the the wall. If you set a radiation source of 1000 W/m^2 (in the radiation tab) the heat will be transported by the radiation solver possibly all the way to another wall if the absorbtion coefficent in the fluid is low.