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Old   January 9, 2012, 03:37
Default Urgent: Pump Boundary Condition
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Hi all,

I'm on a centrifugal pump analysis. My boundary conditions are 1 atm absolute pressure at the inlet and 1.66 atm static pressure at the outlet. Rotating speed of the impeller is 2100 rpm.

As a result, I obtain negative mass flow rate at the inlet which means the fluid flows reversely.

Where am I wrong? What am I supposed to do in order to monitor mass flow rate under known pressure drop values?

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Old   January 14, 2012, 01:37
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Lucky Tran
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A negative mass flow rate can mean that mass is entering the normal boundary. So the mass flow is going into your inlet. Are you sure your mass flow rate is reversed?

Fluent uses the outward facing normal convention for calculating fluxes.

Last edited by LuckyTran; January 14, 2012 at 10:49.
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Old   January 14, 2012, 05:47
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shoeb khan
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Sometimes when the flow is entering from the negative side of x,y or z axis fluent take it as negative mass flow inlet.

Check if that is the case in your situation

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