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-   -   Mdot and P_Flow_Rate in dpm (http://www.cfd-online.com/Forums/fluent/114604-mdot-p_flow_rate-dpm.html)

Alimohamadi_nasr March 13, 2013 21:19

Mdot and P_Flow_Rate in dpm
 
Dear all,
what is the difference between Mdot and P_Flow_Rate in dpm?

Mdot is used in DEFINE_DPM_ACRETION and has dimension of kg/s, and is defined as:
Flow rate of the particle stream as it hits the face (in kg/s).

P_Flow_Rate has same unit and define in Model Specific Macros as :
"Each particle in a steady flow calculation represents a "stream'' of many particles that follow the same path. The number of particles in this stream that passes a particular point in a second is the "strength'' of the stream. P_FLOW_RATE returns the strength multiplied by P_MASS(p) at the current particle position."

but the quantity of these two variable are different and it seems that Mdot is smaller about Mdot=P_Flow_Rate*timestep.

what is the applcation of each of them?

msaeedsadeghi March 14, 2013 01:42

Mdot means whole particles flow rate.
But P_FLOW_RATE means flow rate of each parcell of particles.

Alimohamadi_nasr March 14, 2013 02:44

Dear msaeedsadeghi
thanks for your reply. I check the mass of each parcel. it is equal the Mdot and P_Flow_Rate is the whole particles flow rate. I compare my result from UDF with mass of parcel at "particle Tracks".


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