How can I specify mass flow rate as inlet bc and domain press. info. at same time?

soumitra2102 · December 23, 2018, 20:11

There is a fluid flowing inside a tube and the pressure (3MPa) in the tube is given.

I have also given mass flow rate value at inlet.

How can I define both of the properties in CFX-Pre?
Should I put domain reference pressure as 3MPa (and 0 relative pressure as initial condition)?

or

should I put initial condition as 3MPa relative pressure and 0MPa as domain reference pressure?

ghorrocks · December 24, 2018, 01:56

You cannot specify pressure and velocity at an inlet.

Some options include:
* Specify the pressure at the inlet and the mass flow at the outlet
* Specify the mass flow rate at the inlet and the pressure at an outlet. If the simulation is incompressible you can then simply offset the pressure field to a 3MPa inlet pressure. If the simulation is compressible you may need to try a few outlet pressures until the inlet pressure is correct.

December 23, 2018, 20:11	How can I specify mass flow rate as inlet bc and domain press. info. at same time?	#1
soumitra2102 Member Soumitra Vadnerkar Join Date: Aug 2018 Posts: 70 Rep Power: 8	There is a fluid flowing inside a tube and the pressure (3MPa) in the tube is given. I have also given mass flow rate value at inlet. How can I define both of the properties in CFX-Pre? Should I put domain reference pressure as 3MPa (and 0 relative pressure as initial condition)? or should I put initial condition as 3MPa relative pressure and 0MPa as domain reference pressure?

December 24, 2018, 01:56		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,933 Rep Power: 145	You cannot specify pressure and velocity at an inlet. Some options include: * Specify the pressure at the inlet and the mass flow at the outlet * Specify the mass flow rate at the inlet and the pressure at an outlet. If the simulation is incompressible you can then simply offset the pressure field to a 3MPa inlet pressure. If the simulation is compressible you may need to try a few outlet pressures until the inlet pressure is correct. soumitra2102 likes this. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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