Mdot and P_Flow_Rate in dpm

Alimohamadi_nasr · March 13, 2013, 21:19

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".

March 13, 2013, 21:19	Mdot and P_Flow_Rate in dpm	#1
Alimohamadi_nasr Member Ali Mohamadi Join Date: Aug 2012 Posts: 32 Rep Power: 14	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?

March 14, 2013, 01:42		#2
msaeedsadeghi Senior Member SSL Join Date: Oct 2012 Posts: 226 Rep Power: 15	Mdot means whole particles flow rate. But P_FLOW_RATE means flow rate of each parcell of particles. Alimohamadi_nasr, Strawlee and gush like this.

March 14, 2013, 02:44		#3
Alimohamadi_nasr Member Ali Mohamadi Join Date: Aug 2012 Posts: 32 Rep Power: 14	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". msaeedsadeghi likes this.