Problem with k-epsilon model

torkness · February 17, 2015, 08:58

Hello,
I am trying to create a model of gas injection inside chamber. I created first model with Laminar model. Velocity of air acted as suspected. After changing model into k-epsilon (near-wall treatment - enhanced wall treatment + thermal effects) velocity of air radically changed. Velocity is going down to zero very fast. After that i changed back near wall treatment to standard but it helped only a little bit.

Medium is air, inlet velocity 10m/s. Output is pressure outlet. Both 0 Pa.

Does anyone know how i can fixe my model to get similar velocity distribution in turbulent model?

Sorry if my english is bad. Thank You for help

Here is laminar model:
http://imgbox.com/uayVR7oi

k-epsilon with enhanced wall treatment
http://imgbox.com/xtEWB6G1

k-epsilon
http://imgbox.com/zdGEdpq6

Here is link to my project (in Ansys 14.5)
https://dl.dropboxusercontent.com/u/6374861/13.wbpz

torkness · February 18, 2015, 04:47

OK i solved the problem. It was density model of air. After coming back to constant everything is normal again.

Does anyone know good density model of air i can use?
Still my heat exchange between air and solid is lame. Flow of air with temperature of 9k°C after 600s is rising temperature of aluminium body for only 100°C (from 300°C).

Does anyone handled similar problem?

torkness · February 27, 2015, 02:44

How anyone can get some help here? >_<

February 17, 2015, 08:58	Problem with k-epsilon model	#1
torkness New Member Dawid Join Date: Jun 2014 Posts: 14 Rep Power: 11	Hello, I am trying to create a model of gas injection inside chamber. I created first model with Laminar model. Velocity of air acted as suspected. After changing model into k-epsilon (near-wall treatment - enhanced wall treatment + thermal effects) velocity of air radically changed. Velocity is going down to zero very fast. After that i changed back near wall treatment to standard but it helped only a little bit. Medium is air, inlet velocity 10m/s. Output is pressure outlet. Both 0 Pa. Does anyone know how i can fixe my model to get similar velocity distribution in turbulent model? Sorry if my english is bad. Thank You for help Here is laminar model: http://imgbox.com/uayVR7oi k-epsilon with enhanced wall treatment http://imgbox.com/xtEWB6G1 k-epsilon http://imgbox.com/zdGEdpq6 Here is link to my project (in Ansys 14.5) https://dl.dropboxusercontent.com/u/6374861/13.wbpz Last edited by torkness; February 18, 2015 at 01:46.

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February 18, 2015, 04:47		#2
torkness New Member Dawid Join Date: Jun 2014 Posts: 14 Rep Power: 11	OK i solved the problem. It was density model of air. After coming back to constant everything is normal again. Does anyone know good density model of air i can use? Still my heat exchange between air and solid is lame. Flow of air with temperature of 9k°C after 600s is rising temperature of aluminium body for only 100°C (from 300°C). Does anyone handled similar problem?

February 27, 2015, 02:44		#3
torkness New Member Dawid Join Date: Jun 2014 Posts: 14 Rep Power: 11	How anyone can get some help here? >_<