Report - Mass Flow at Outlet Boundary

Dee Kay · October 17, 2024, 20:40

Hi All,

I am simulating a compressed air pipe flow in a long meandering pipe network with an operating pressure of ~ 650 KPa.

I am plotting the mass flow rate at the outlet and it has this profile attached. I've also attached the absolute pressure plot at the same location.

What is the physical interpretation of this plot? I expect a Mass Flow rate of ~ 65 kg/ s at this location.

Thank you for assisting.

MKuhn · October 18, 2024, 08:36

You get it. I can't say exactly, as the grid lines are missing, but it should be around 70 kg/s. The pressure drop is around 94 kPa. You have the operating at the inlet and the absolute pressure at the outlet. Since the pressure at the outlet is higher than at the inlet, your medium flows in the opposite direction. This is reason, that you have a negative massflow in your plot.

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October 18, 2024, 08:36		#2
MKuhn Senior Member Moritz Kuhn Join Date: Apr 2010 Location: Germany, Dresden Posts: 218 Rep Power: 17	You get it. I can't say exactly, as the grid lines are missing, but it should be around 70 kg/s. The pressure drop is around 94 kPa. You have the operating at the inlet and the absolute pressure at the outlet. Since the pressure at the outlet is higher than at the inlet, your medium flows in the opposite direction. This is reason, that you have a negative massflow in your plot.