Discussion Forum

Dear All,
I have simulated a resistive heater model (1200um x 80000um; width of heating element- 50 um) and used the shell model approximation by coupling 'Electric current, Shell' and 'Conjugate heat transfer' physics to incorporate the joule heating effect.

I have done the steady state analysis wherein I have obtained a temp of 293.16K compared to the normal temp of 293.15K i.e. an increment of just 0.01K with a fluid flow and i/p voltage of 1V. However, transient analysis of the same for 0.02s gave a max temp of about 45000K with the same flow. I would like to know why their is such a huge temperature difference coming up?

The range settings for transient analysis for 0.02s were- range (0, 0.001,0.02) and it took about 12.5 hrs to compute. Here the convergence plot showed saturation after about 100 time steps corresponding to 0.005 sec. Thus I had also set a diff settings of range (0, 0.0005,0.005) which took about 5 hrs to compute. In none of the cases the graph plot for temperature vs time is saturating although the convergence plot showed a saturation value. Hence I think the it needs to solve for a greater time for the transient analysis to complete. However it is taking quiet a long time to do so. I shall be highly obliged if anyone can kindly help me with the above problem to solve the above temerature ambiguity and longer solution time.

Looking forward for your help,
Thanks,
Debashis