[dhiraj kumar]

hello everyone. I have a solar receiver tube in which at outer surface of the receiver I have to apply non-uniform heat flux [cosine profile - q(θ) = qnet ·
cos θ(−90 ≤ θ ≤ 90)] with radiation and convection losses to ambient.

radiation loss = σεS[T^4 - Tsky^4]
where: ε = 0.95
s = outer face surface area
Tsky = 278 k

convection loss = hS(T − Ta)
where : h = 50 w/k-m^2
Ta = 298 k

Can anyone give me the idea for writing the UDF for Ansys fluent for this condition.

Thanks !