[YOUNS]

Hello guys.

I work CFD analysis by turbine and turbine housing of the turbocharger(twin scroll, Inlet scroll of turbine housing is two.).
Final purpose is verify thermal distribution on the Backplate which is backside radial turbine.
Here, I have boundary conditions from engine by Inlet temperature, Inlet mass flow, Outlet pressure and turbine speed.
This is:
Inlet Temperature: 922.6 deg.C
Inlet Mass Flow: 0.27 kg/s
Outlet Pressure: 188.8 kPa
Turbine rotational speed: 160,000 rpm


Here, I set mass flow 0.135 kg/s and 922.6 deg.C each inlet ( 0.135 + 0.135 = 0.27 ), rotation speed: 160,000 rpm.
But, To you guys know, it can't set total pressure at outlet.
So I set 0.27 kg/s mass flow.

But.... I gave the message "Overflow" from CFX solver....
Mach number is expressed very high in solver message...

How to set boundary condition by this condition?

[ghorrocks]

Defining the mass flow in and out is numerically badly posed. It is never going to converge. Read the CFX documentation on choice of boundary conditions and the best practises guide for turbomachinery.

In you case you should probably put a mass flow outlet boundary and a total pressure inlet.