Learning Forum

[divpatel]

I m doing ANSYS fluent simulation, where the fluid is the water, the solid portion is the fins, and the flow is flowing at Reynolds of 20, so laminar flow with energy turned on, and heat flux of 10000 w/m^2 is being added to the system from the top, here i have given the flow and the solid the initial temp of 300k , but the solid has the sudden jump in temperature, and then slowly rises which makes sense as it heats from the top more heat is progressively going to get transferred from fluid to solid, what i cant explain is the sudden temperature jump .

i have attached some pictures, if someone can let me know about this, of if I have set the initial temp in wrong way. do let me know thank you,

[Karthik R]

Thermal resistance on the fin side is much lower compared to the fluid - primarily driven by the high thermal conductivity. Is this what you are experiencing?

[Rob]

And maybe answer my question in here too https://forum.ansys.com/discussion/37005/sudden-temperature-jump-for-solid

[divpatel]

its steady state analysis in fluent

[Rob]

If you're adding heat to a solid, why would the boundary sit at the initial temperature?

[divpatel]

I m adding heat flux to the top part which has a 1mm gap between it and the fins and as seen i have the line measuring temp at the bottom, i thought i d see a major temp contour from top to bottom but i think it just gains that extra energy cuz of better heat conduction in solids

[Rob]

And in steady state we're modelling the equilibrium condition. The heat flux bc will raise the temperature in the wall cells to reach the set flux value: this can lead to very high temperatures if the flow can't carry the heat away.