Hell, how can we write a UDF to include a heat flux value + convection coefficient for a wall in Fluent because we cannot define two named selections for 1 wall ?
Danke!
And I'm completely in agreement that you can only define one.
With respect
Dusan
Dear Ahmed S. Mansour ,
I agree. To make it clear, please think about an electric heater in the air environment. Physically, there exists the heat flux (e.g. in Watt/m2) and the free heat convection between the outer surface of the heater and the air. But the value of the heat transfer coefficient is depend on the heat flux and the air condition. Conversely, if we give hot air to the heater, then there is convection heat transfer to the heater wall (there is heat transfer coefficient), then we can calculate the heat flux value on the heater surface. Therefore, the two parameters are interdependent. So all we need is just to know (as an input or boundary condition) one parameter.
I hope it can make you clear....
It's easy , just fixed the stream and wall temperatures , both variable will be included as a ratio. Q/A= h * dt ... so that (Q/A)/h=dt
Regards
Hello dear Nazaruddin Sinaga and Alaa Temimy , simply we have a wall that is exposed to a heat flux for example 500 W/m^2 and at the same time it is cooled by the outside air. So we have radiation + convection. The radiation warms up the wall and the convection cools it. In ANSYS thermal, we can define both easily on the same wall.
But in FLUENT this is not allowed. The method I know is to include the heat source in the domain to select its wall to define the heat flux, then we can select the other wall and define the convection coefficient.
The heat transfer by radiation will occur and heats up the wall and also the convection will cool it. Then we can reach the solution of the temperature distribution of the wall. I just wanted to know if there was an easier way like ANSYS thermal.
Vielen vielen Dank und viel Erfolg !
Dear Ahmed S. Mansour , in your case study , you should activate radiation model first , then you can select a mixed heat sources of radiation and convection.
Regards.
Ahmed S. Mansour i guess you can add just one BC at a surface (unless the BCs work in synergy like convection and radiation).
Thank you dear Zahid Ahmed Qureshi :) and thank you so much dear Alaa Temimy for the wonderful pdf !
Vielen vielen Dank !
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