measure flow through a hole in cfd post

gitsnedbutzi · August 19, 2010, 10:10

Hi,

I have a problem in CFD post.
Inside my fluid domain, I have a structure which has two holes for an opening.
I want to compare the fluid flow of those two holes.
I could use an expression to evaluate the mass flow.
However I dont have a location (plane, etc.) for those two holes.
Is it possible to select create a location for the hole?

The geometry looks something like this:

Code:

---  ----  ---
¦     ¦      ¦
¦     ¦      ¦
¦     ¦      ¦
¦     ¦      ¦
--------------

Thanks a lot!

ghorrocks · August 19, 2010, 19:26

Yes. It is a bit clunky but it can be done. You need to define a surface to integrate the flow over somehow - options include planes with limits, contour surfaces or I think you can import XYZ points as user surfaces. Then use the function calculator to get the flow rate (or whatever you want) across the surface.

gitsnedbutzi · August 20, 2010, 06:19

thanks, that helped. now i can calculate the massflow with an expression, but how could i calculate the heat flow?

ghorrocks · August 22, 2010, 19:29

use the function calculator to get the heat flux integrated over the surface.

gitsnedbutzi · August 23, 2010, 04:20

but it says that the variable is not available on the plane. is it in general only available on boundaries and interfaces, as it says in the help or is there a chance to use it on planes?

ghorrocks · August 23, 2010, 08:36

Sorry, I meant general heat flux, not the variable heat flux which is only at the walls. Integrate the enthalpy.

August 19, 2010, 10:10	measure flow through a hole in cfd post	#1
gitsnedbutzi New Member name Join Date: Mar 2009 Posts: 9 Rep Power: 17	Hi, I have a problem in CFD post. Inside my fluid domain, I have a structure which has two holes for an opening. I want to compare the fluid flow of those two holes. I could use an expression to evaluate the mass flow. However I dont have a location (plane, etc.) for those two holes. Is it possible to select create a location for the hole? The geometry looks something like this: Code: --- ---- --- ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ ¦ -------------- Thanks a lot!

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August 19, 2010, 19:26		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Yes. It is a bit clunky but it can be done. You need to define a surface to integrate the flow over somehow - options include planes with limits, contour surfaces or I think you can import XYZ points as user surfaces. Then use the function calculator to get the flow rate (or whatever you want) across the surface.

August 20, 2010, 06:19		#3
gitsnedbutzi New Member name Join Date: Mar 2009 Posts: 9 Rep Power: 17	thanks, that helped. now i can calculate the massflow with an expression, but how could i calculate the heat flow?

August 22, 2010, 19:29		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	use the function calculator to get the heat flux integrated over the surface.

August 23, 2010, 04:20		#5
gitsnedbutzi New Member name Join Date: Mar 2009 Posts: 9 Rep Power: 17	but it says that the variable is not available on the plane. is it in general only available on boundaries and interfaces, as it says in the help or is there a chance to use it on planes?

August 23, 2010, 08:36		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Sorry, I meant general heat flux, not the variable heat flux which is only at the walls. Integrate the enthalpy.