When I use cfx to analyze the twin screw expander with material air ,how can I set up

Damon · August 10, 2017, 01:24

Once I use the air Ideal gas ,it will go to error in 5 steps. And when I use the IAPWS IF97 ,it can work successfully.

ghorrocks · August 10, 2017, 04:11

You are comparing an air simulation to a water simulation. There are lots of reasons why that could cause problems.

Damon · August 10, 2017, 04:40

When the air expand in the expander ,the temperature, dencity and preasure will decrease with the increase of the volume ,I don't know whether air Ideal gas model is suitable for this simulation.

Damon · August 10, 2017, 04:41

Quote:

Originally Posted by ghorrocks

You are comparing an air simulation to a water simulation. There are lots of reasons why that could cause problems.

When the air expand in the expander ,the temperature, dencity and preasure will decrease with the increase of the volume ,I don't know whether air Ideal gas model is suitable for this simulation.

ghorrocks · August 10, 2017, 04:48

I don't know either. This might help: https://www.cfd-online.com/Wiki/Ansy...ible_answer.3F

August 10, 2017, 01:24	When I use cfx to analyze the twin screw expander with material air ,how can I set up	#1
Damon New Member Wang Xinwei Join Date: May 2017 Posts: 4 Rep Power: 9	Once I use the air Ideal gas ,it will go to error in 5 steps. And when I use the IAPWS IF97 ,it can work successfully.

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August 10, 2017, 04:11		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	You are comparing an air simulation to a water simulation. There are lots of reasons why that could cause problems.

August 10, 2017, 04:40		#3
Damon New Member Wang Xinwei Join Date: May 2017 Posts: 4 Rep Power: 9	When the air expand in the expander ,the temperature, dencity and preasure will decrease with the increase of the volume ,I don't know whether air Ideal gas model is suitable for this simulation.

August 10, 2017, 04:48		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	I don't know either. This might help: https://www.cfd-online.com/Wiki/Ansy...ible_answer.3F