CFD post-Fluid mean temperature plot

gtheo · June 6, 2011, 06:08

Hello,

I'm using ANSYS CFX v13 to simulate the conjugate heat transfer inside a duct. I'm using CFD-post to process my results and I would like to plot a line along the flow direction with the values of the fluid MEAN temperature (in every cross section).

Can I do that in CFD post, without having to take a number of planes in various cross sections and export the fluid temperature values in order to calculate the mean in each cross section? Is there another (easier) way?

Thank you in advance!

kambireddy · June 6, 2011, 07:27

Create a variable for Avg temp at plane perpendicular to axial direction. then create chart with x axis as axial distance and y axis as avg temp over plane. Note: in Data series u need to add middle line as data series line..

gtheo · June 6, 2011, 10:01

I'm sorry, I don't quite understand, so I hope you could explain it to me a bit more.

If the flow is along the Z axis,and X axis is transversal to the flow at the horizontal pane you suggest I should create a XZ plane for Y=middle of the duct?

How can I create a variable with the mean fluid temperature? This variable should take the average temperature value in each cross section. Furthermore, how can I create a variable on a plane?

Finally, the data series for a chart should be lines (not planes). You mention that I should also create a line. The line should have the values of the avg temperature?

Thank you for your help!

kambireddy · June 6, 2011, 10:30

"If the flow is along the Z axis,and X axis is transversal to the flow at the horizontal pane you suggest I should create a XZ plane for Y=middle of the duct?"

If the flow is x direction, then you need create xy plane say plane1. over xy plane you can calculate mean temperature.

Then go to CEL expressions, create new expression as areaAve(Temperature)@Plane1. then go to variable create new variable name "avg temp" and insert above expression.

Create one line for data series. then add axial distance i.e., z in x axis and avg temp in y axis.

Hope you got it.

gtheo · June 15, 2011, 07:27

Thank you for the help!

The problem is that I need the local mean temperature along the direction of the flow and not just the mean value over the entire plane (which is only ONE value). To be more specific, I need the local mean temperature along a line in the symmetry plane of the duct, so I could create several lines perpendicular to the flow and calculate the mean temperature at each line. Each result would be the mean temperature for the specific location (point). The temperature distribution I want, would then result from the total of the points.

Is there a way to create this distribution without having to create sample lines or planes ?

Sorry if I'm becoming tiresome!!

ghorrocks · June 15, 2011, 08:46

You will need to generate the sampling lines or planes. But this can all be scripted so you just record a session file of you generating one object, then edit the session file to generate lots of them when you play it back. I assume you are also exporting this to some external package - the export can also be scripted.

velu · August 19, 2014, 11:49

can u tel me hw to take temp distribution in CFD post for a rod having conduction convection and heat generation in YZ plane..
actually i ve created YZ plane as u said. and in expressions i ve selected areaAvg but im unable to get temperature in the variable select box...

sanjeetlimbu · April 19, 2015, 15:38

Dear sir

I am doing a 2D asymmetric case for cylinder - y axis is my axis.... the plane is xy. It is a dynamic mesh - compression stroke only.
I am not able to plot the CFD post chart for the maximum temperature which is needed for comparison with empirical values..

Though I plotted the chart temp vs time for a point location .... but I am unable to do for the maximum temperature vs time...

Please suggest how to get that plot in CFD post ... ansys

Thanks !

regards
Sanjeet

ghorrocks · April 19, 2015, 19:52

Define the y variable to be a CEl expression like maxVal(T)@domain or something like that.

sanjeetlimbu · April 19, 2015, 21:51

thanks! a lot

sanjeetlimbu · April 23, 2015, 12:38

Hi I am unable to create that maximum temperature expression... can u share in detail...as I am very new to CFD post.

Also can u tell how to export the data into excel ... As I wanna compare two different case results, like one using k-e epsilon and other from RNG viscous model

Thanks

ghorrocks · April 23, 2015, 19:30

I already showed you how to implement the expression. If it is not working for you then post the error message you are getting.

Also, make sure you have done the CFX tutorials. They explain how to do the basics like this.

roi247 · November 17, 2015, 20:18

It's useful to me

S_teph_2000 · March 28, 2016, 23:27

Quote:

Originally Posted by ghorrocks

You will need to generate the sampling lines or planes. But this can all be scripted so you just record a session file of you generating one object, then edit the session file to generate lots of them when you play it back. I assume you are also exporting this to some external package - the export can also be scripted.

it's been a few years so...did you find a more "Elegant" way to do this?

ghorrocks · March 28, 2016, 23:48

No, a session file is still how I would do this. But don't forget that session files can include perl, so can include looping, branching, file IO, complex variable manipulation etc... Does that qualify as "elegant"?

June 6, 2011, 06:08	CFD post-Fluid mean temperature plot	#1
gtheo New Member George Theo Join Date: Apr 2011 Posts: 13 Rep Power: 15	Hello, I'm using ANSYS CFX v13 to simulate the conjugate heat transfer inside a duct. I'm using CFD-post to process my results and I would like to plot a line along the flow direction with the values of the fluid MEAN temperature (in every cross section). Can I do that in CFD post, without having to take a number of planes in various cross sections and export the fluid temperature values in order to calculate the mean in each cross section? Is there another (easier) way? Thank you in advance!

November 17, 2015, 20:18	Thank you for the help	#13
roi247 Member Rui Join Date: Apr 2015 Location: Montreal. CA Posts: 49 Rep Power: 11	It's useful to me

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June 6, 2011, 07:27		#2
kambireddy New Member Redddy Join Date: Sep 2010 Posts: 25 Rep Power: 16	Create a variable for Avg temp at plane perpendicular to axial direction. then create chart with x axis as axial distance and y axis as avg temp over plane. Note: in Data series u need to add middle line as data series line..

June 6, 2011, 10:01		#3
gtheo New Member George Theo Join Date: Apr 2011 Posts: 13 Rep Power: 15	I'm sorry, I don't quite understand, so I hope you could explain it to me a bit more. If the flow is along the Z axis,and X axis is transversal to the flow at the horizontal pane you suggest I should create a XZ plane for Y=middle of the duct? How can I create a variable with the mean fluid temperature? This variable should take the average temperature value in each cross section. Furthermore, how can I create a variable on a plane? Finally, the data series for a chart should be lines (not planes). You mention that I should also create a line. The line should have the values of the avg temperature? Thank you for your help!

June 6, 2011, 10:30		#4
kambireddy New Member Redddy Join Date: Sep 2010 Posts: 25 Rep Power: 16	"If the flow is along the Z axis,and X axis is transversal to the flow at the horizontal pane you suggest I should create a XZ plane for Y=middle of the duct?" If the flow is x direction, then you need create xy plane say plane1. over xy plane you can calculate mean temperature. Then go to CEL expressions, create new expression as areaAve(Temperature)@Plane1. then go to variable create new variable name "avg temp" and insert above expression. Create one line for data series. then add axial distance i.e., z in x axis and avg temp in y axis. Hope you got it.

June 15, 2011, 07:27		#5
gtheo New Member George Theo Join Date: Apr 2011 Posts: 13 Rep Power: 15	Thank you for the help! The problem is that I need the local mean temperature along the direction of the flow and not just the mean value over the entire plane (which is only ONE value). To be more specific, I need the local mean temperature along a line in the symmetry plane of the duct, so I could create several lines perpendicular to the flow and calculate the mean temperature at each line. Each result would be the mean temperature for the specific location (point). The temperature distribution I want, would then result from the total of the points. Is there a way to create this distribution without having to create sample lines or planes ? Sorry if I'm becoming tiresome!!

June 15, 2011, 08:46		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	You will need to generate the sampling lines or planes. But this can all be scripted so you just record a session file of you generating one object, then edit the session file to generate lots of them when you play it back. I assume you are also exporting this to some external package - the export can also be scripted.

August 19, 2014, 11:49		#7
velu New Member velmurugan Join Date: Feb 2014 Location: VIT University, Vellore Posts: 2 Rep Power: 0	can u tel me hw to take temp distribution in CFD post for a rod having conduction convection and heat generation in YZ plane.. actually i ve created YZ plane as u said. and in expressions i ve selected areaAvg but im unable to get temperature in the variable select box...

April 19, 2015, 19:52		#9
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Define the y variable to be a CEl expression like maxVal(T)@domain or something like that.

April 19, 2015, 21:51		#10
sanjeetlimbu Member sanjeet Limbu Join Date: Mar 2015 Posts: 91 Rep Power: 11	thanks! a lot

April 23, 2015, 12:38		#11
sanjeetlimbu Member sanjeet Limbu Join Date: Mar 2015 Posts: 91 Rep Power: 11	Hi I am unable to create that maximum temperature expression... can u share in detail...as I am very new to CFD post. Also can u tell how to export the data into excel ... As I wanna compare two different case results, like one using k-e epsilon and other from RNG viscous model Thanks

April 23, 2015, 19:30		#12
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	I already showed you how to implement the expression. If it is not working for you then post the error message you are getting. Also, make sure you have done the CFX tutorials. They explain how to do the basics like this.

March 28, 2016, 23:48		#15
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	No, a session file is still how I would do this. But don't forget that session files can include perl, so can include looping, branching, file IO, complex variable manipulation etc... Does that qualify as "elegant"?