I the following changes to the previous model:
1) Set the operating density to density of SCCO2
2) Changed the outlet BC from "Outflow" to "Pressure outlet BC".
The red plot is the new model with pressure outlet BC and specified operating density, while the blue is the previous model with outflow BC.
The model looks better as the magnitude of the fluctuations is smaller than the previous one, but it still has some fluctuations.
I observed something about the model.
- For both models, when there is no reverse flow, there are no fluctuations or overshoots. At 224 seconds, the reverse flow is about 0.4 %, and fluctuations were not observed. But at 381 seconds, the reverse flow was about 38%, and the fluctuations were pronounced during those times. Maybe the reverse flow at the outlet causes the fluctuations/overshoots in the plot.
Do you have any ideas how to eliminate/reduce the reverse flow? I have extended the domain, but it doesn't seems to help.
Thank you for your time.