Learning Forum

[Андрей Ромашов]

Hello. As title suggests I'm trying to simulate a solar collector.

I have modelled 2 parabolic mirrors which focus incident sun beams onto a central pillar. Mirrors and the pillar are cooled by natural convection in surrounding air. The goal is to determine steady state temperature in the focal point of the mirrors. I have tried using solar loads in Fluent with or without DO radiation model enabled. In both cases incident solar radiation seems to heat up the pillar and mirrors as expected, although reflected radiation does not seem to heat up anything. So I have 2 questions:

1) Does Solar Loading in Fluent simulate heating by reflected sun beams?

2) How would you approach solving this problem?

Thanks in advance.

[Rob]

Solar load is merely the direct contribution from the sun to the system energy. You also need a radiation model to then account for focussing & bouncing of the energy. DO, S2S or Monte Carlo will work, assuming there's no absorbtion by the gas or solids I'd go with S2S. I'd also be wary of the solar load model, other than to determine the direction and intensity of the energy: read up on what the model does to make sure you're using the right part of it. 

[Jon Reed]

I am trying to do something similar and was hoping to get further guidance...

I have modelled a small parabolic torugh collector and a hollow cylindrical receiver filled with water, yet I cannot seem to achieve any sort of temperature rise at the pipe outlet.

What parameters/ set-up conidtions should be used?

I am an ANSYS amateur I'm afraid! 

[Rob]

Heat transfer will be by absorption, so what are the material properties & is the tube transparent/reflecting/aborbing energy? Which radiation model as they don't all see the fluid/solid material in the same way.