Nonconservation of energy when using system-level heat exchanger
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轩 on 24 Nov 2022
Commented: 轩 on 30 Dec 2022
Hello, when I try the heat exchanger model, I find something weird.
For fluid 1 (left), G(h_in-h_out)=125249.28kJ/s, however, for fluid 2 (right), G(h_out-h_in)=21143.1kJ/s.
I can not figure out where the problem is. If anyone can help me, thank a lot.
Yifeng Tang on 22 Dec 2022
I downloaded the model and noticed the flowrate on the right is very large. As you are still using the default port size (0.01m^2) for all the blocks, the local velocity can be very large (~50m/s), which means significant amount of enthalpy. For example, see line 315 of the source code of the reservoir block. Changing the port size to a much more reasonable value, say 0.5m^2, and you'll see the G*dh will again be (almost) conserved.
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