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Centrifugal fan P-Q characteristics

Question asked by Xenofon Kalogeropoulos on Feb 27, 2014
Latest reply on Feb 27, 2014 by Jared Conway

Hi everyone,


I have modelled up a small centrifugal fan (Scroll + Impeller ~40mm O.D.) and now I would like to obtain its characteristic performance (P-Q) curve.

My blower is discharging into an open environment (atmospheric pressure / room temperature)


I have set up my simulation the following way:


-Internal Analysis + local rotating region

-Fluid medium: air


  1. B.C.s


-Rotating speed of the impeller: 7000 rpm

-Real wall bounbdarr on the scroll walls

-Local Initial mesh on the impeller body



Now I am strugling to understand how to set up the next two BCs. Which is the correct way?


  1. Define the Inlet Static Pressure and the Environmental Outlet Pressure and solve for Outlet Flow rate?


  1. Define the Inlet Flow rate and the Environmental Outlet Pressure and solve for Inlet Static Pressure?


Ideally my intuition says that If I want to find the Pressure as a function of Flowrate [P(Q)], I should set the Outlet Flowrate and then let the solver compute the inlet Pressure.

But apparently I cant define both the Environmental Pressure Condition and the Outlet Flowrate on the outlet Lid.


So what do you think guys? Will option 1 or 2 give me the proper PQ characteristics or do I have to follow another approach that I haven't thought of?


I would welcome your thoughts and suggestions.


Best regards