I'm trying to simulate the solar radiation for the solar collector using the DO radiation model available in ANSYS-Fluent. I'm using the solar ray tracing model as a solar load, and thus solar ray is converted to heat, and absorbed by the working fluid. I'm using the incident solar radiation value, 10,000 W/m^2 (, which is equivalent to 10 suns) as an input to the collector's top surface (Jusy a Face, not body), which is expected to be uniform on the face. I considered the non-gray surface and solar wavelength was in a range between 0.5um to 1.5 um.
I've checked with angular discretization, mesh study. Then, I've done the set up of the DO model following the above criteria, like as follows:
After that, I followed the necessary fluid properties, and set up for the solar inlet face as follows:
I found a good convergence, but I'm not sure about the outcome (Wall flux--->surface incident radiation, /m^2), as it shows not exactly the same value that I input as incoming solar radiation. Moreover, wall flux--->sun heat flux is zero on the top face.
I suspect the reason for such a curve rather than a uniform manner is the absorption coefficient value of the working fluid. In fact, there is no solid body considered for glass (solar window) but only face.
Could you please guide me, whether my DO model set up is ok or not?
Is the direction value ok in terms of Sun direction vector, beam direction?
And, which solar radiation value (surface incident radiation/incident radiation) represents my actual incoming radiation?
Thanks in advance.