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Potato in microwave oven : problem in pulsing microwave source

Posted 21.01.2018, 13:38 GMT-5 2 Replies

Prateek Katare
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Hello!

I was fiddling around with the "potato in microwave" example of microwave heating and noticed that it uses continous microwave heating. Practically, at < 100% power setting, the microwave uses PWM.

So I defined an analytic function to mimic the pulsed microwave source (at 20% duty cycle) and fed it into the "P in" part of the EMW (electromagnetic waves) physics

However, I got the same results as the full-power (100% futy cycle). I even changed the solver to "Strict" but no difference.

I also made another model that uses only "heat transfer" and fed the analytic function to its "heat source" section - this was successful and the heating plots follow the periodicity of the defined function.

So what did I miss here? Why does coupling two physics (EMW and HT) in the potato heating simulation mislead COMSOL into treating a pulsed source as just a continous source?

Thanks in advance !

2 Replies Last Post 19.02.2018, 05:04 GMT-5
Sohan Birla
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Posted: 6 years ago 26.01.2018, 15:31 GMT-5

Prateek, If your material dielctric proeprties are not temperature dependent, the EM solver do not see the need for calcualting EM field for marching time steps.

Prateek, If your material dielctric proeprties are not temperature dependent, the EM solver do not see the need for calcualting EM field for marching time steps.
Prateek Katare
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Posted: 6 years ago 19.02.2018, 05:04 GMT-5

Thanks Sohan

I eventually tried a frequency-transient study and it worked just fine. Couple of points to be noted though 1) Solver must be "strict" 2) The study needed to be "segregated" else the solution never converged.

So now I have the pulsed EM heating simulation working just fine.

Thanks Sohan I eventually tried a frequency-transient study and it worked just fine. Couple of points to be noted though 1) Solver must be "strict" 2) The study needed to be "segregated" else the solution never converged. So now I have the pulsed EM heating simulation working just fine.

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