Air at High Pressure

cfd seeker · September 29, 2013, 06:35

Hi Dear fellows

I am trying to model the Air Reducer/Pressure Reducer in Fluent. The Inlet pressure is 250 bars and mass flow rate is 0.36 kg/s. The desired outlet pressure is around 8-9 bars.

I am using Pressure inlet boundary condition @inlet and Mass flow inlet boundary condition @outlet(with appropriate direction vectors so that mass flow out from the outlet).

Since air is compressed at high pressure of 250 bars so Ideal gas model cannot be used. I have read that due to high variation of temperature from inlet to outlet Peng-Robinson Real Gas model should be used instead. But when I set this model in the materials panel for air and compute Reference values from the Inlet boundary, the density reported is very very less i.e of the orders of 10^-5. In actual scenario the density is high(around 300 kg/m^3) due to high pressure at which the air is stored in air bottles.

I don't know what mistake I am making....if any body has done such problem or has handled air at high pressures or used real gas models for air in Fluent kindly help me.

Thanks in advance.
Regards

like.no.other · September 30, 2013, 08:49

Hi
I think you should use able-noble EOS in High pressure and temperature flow

cfd seeker · September 30, 2013, 15:58

Thanks for your reply.

Can you tell me what's the specialty of this model?

September 29, 2013, 06:35	Air at High Pressure	#1
cfd seeker Senior Member Join Date: Mar 2011 Location: Germany Posts: 552 Rep Power: 20	Hi Dear fellows I am trying to model the Air Reducer/Pressure Reducer in Fluent. The Inlet pressure is 250 bars and mass flow rate is 0.36 kg/s. The desired outlet pressure is around 8-9 bars. I am using Pressure inlet boundary condition @inlet and Mass flow inlet boundary condition @outlet(with appropriate direction vectors so that mass flow out from the outlet). Since air is compressed at high pressure of 250 bars so Ideal gas model cannot be used. I have read that due to high variation of temperature from inlet to outlet Peng-Robinson Real Gas model should be used instead. But when I set this model in the materials panel for air and compute Reference values from the Inlet boundary, the density reported is very very less i.e of the orders of 10^-5. In actual scenario the density is high(around 300 kg/m^3) due to high pressure at which the air is stored in air bottles. I don't know what mistake I am making....if any body has done such problem or has handled air at high pressures or used real gas models for air in Fluent kindly help me. Thanks in advance. Regards

September 30, 2013, 08:49		#2
like.no.other Member like.no.other Join Date: Sep 2011 Posts: 35 Rep Power: 15	Hi I think you should use able-noble EOS in High pressure and temperature flow __________________ www.CFDiran.ir

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September 30, 2013, 15:58		#3
cfd seeker Senior Member Join Date: Mar 2011 Location: Germany Posts: 552 Rep Power: 20	Thanks for your reply. Can you tell me what's the specialty of this model?