The Wall Heat Flux has no value

song · May 22, 2012, 07:16

Hi,dears
I am work on a simulation on cfx 11.0.
There is "fulid solid" interface which is the surface of a blade with cooling tunnels in it.
The tempreture distribution of the blade surface is correct compared to a literature ,and the trend of Wall Heat transfer coffient is nomal (but the value is about 10 times bigger than it in literature)
But the Wall Heat Flux shows zero at the whole area of the interface of the fluid domain ,and the interface at solid domain has a few area with value at the tip and boot.
And if relation h=Q/(wall temperature-Bulk Temperature) is used in cfx, why does the Wall Heat transfer coffient have such value?

Thanks vary much!

ghorrocks · May 22, 2012, 07:28

Have you set the convection bulk fluid reference temperature? There will be a comment in your output file about this.

song · May 22, 2012, 08:28

Have you set the convection bulk fluid reference temperature? There will be a comment in your output file about this.

hi, ghorrocks, thank you for your reply!
I have not set the reference temperature and where can I find this set? I didn't find it.
Is it have a default value if it didn't set it since the heat transfer cofficient already had its value? So what is the problem with Wall heat flux?I was planning to calculate the heat transfer cofficient manually by using Wall heat flux.
Thank you!

ghorrocks · May 22, 2012, 08:35

Just look on the other side of the interface to get the wall heat flux.

Your other questions are best answered by doing some tutorial examples.

song · May 22, 2012, 08:47

I have looked the other interface side (solid side) and more than 95% of the area shows zero and only have values at tip and root which is wrong physically. So I wonder if there was something wrong in my settings.
Thank you!

song · May 29, 2012, 02:38

Problem resolved.
I used CFX 13.0 instead of 12.0, then Wall Heat Flux is OK ...

May 22, 2012, 07:16	The Wall Heat Flux has no value	#1
song New Member Join Date: May 2012 Posts: 4 Rep Power: 14	Hi,dears I am work on a simulation on cfx 11.0. There is "fulid solid" interface which is the surface of a blade with cooling tunnels in it. The tempreture distribution of the blade surface is correct compared to a literature ,and the trend of Wall Heat transfer coffient is nomal (but the value is about 10 times bigger than it in literature) But the Wall Heat Flux shows zero at the whole area of the interface of the fluid domain ,and the interface at solid domain has a few area with value at the tip and boot. And if relation h=Q/(wall temperature-Bulk Temperature) is used in cfx, why does the Wall Heat transfer coffient have such value? Thanks vary much!

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May 22, 2012, 07:28		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	Have you set the convection bulk fluid reference temperature? There will be a comment in your output file about this.

May 22, 2012, 08:28		#3
song New Member Join Date: May 2012 Posts: 4 Rep Power: 14	Have you set the convection bulk fluid reference temperature? There will be a comment in your output file about this. hi, ghorrocks, thank you for your reply! I have not set the reference temperature and where can I find this set? I didn't find it. Is it have a default value if it didn't set it since the heat transfer cofficient already had its value? So what is the problem with Wall heat flux?I was planning to calculate the heat transfer cofficient manually by using Wall heat flux. Thank you!

May 22, 2012, 08:35		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	Just look on the other side of the interface to get the wall heat flux. Your other questions are best answered by doing some tutorial examples.

May 22, 2012, 08:47		#5
song New Member Join Date: May 2012 Posts: 4 Rep Power: 14	I have looked the other interface side (solid side) and more than 95% of the area shows zero and only have values at tip and root which is wrong physically. So I wonder if there was something wrong in my settings. Thank you!

May 29, 2012, 02:38		#6
song New Member Join Date: May 2012 Posts: 4 Rep Power: 14	Problem resolved. I used CFX 13.0 instead of 12.0, then Wall Heat Flux is OK ...