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-   -   Urgent: Pump Boundary Condition (http://www.cfd-online.com/Forums/fluent/95957-urgent-pump-boundary-condition.html)

husker January 9, 2012 03:37

Urgent: Pump Boundary Condition
 
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?

Regards

LuckyTran January 14, 2012 01:37

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.

shk12345 January 14, 2012 05:47

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

shk


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