[MNMK]

Hello,

I would like to adjust my heat flux according to the wall temperature during my simulation. This means that when the temperature @ user location reaches ( Y ), the heat flux should be ( Z ). Therefore, I first write an expression for the location temperature (e.g., probe(Temperature)@user Location). Then I use this in the second expression as I mentioned above.

However, I encountered an error: “The following unrecognized name was referenced: user location.”


Can anyone guide me please?

wishes,

[ghorrocks]

The CFX reference manual says the <Location> for the @probe function should be a point object, giving examples of a source point of a cartesian monitor point. Did you define your point as a source point or a cartesian monitor point?

[MNMK]

Hi Glenn,

I would like to be able to change my heat source (W) by changing the temperature of my user location, e.g., ´TL=Probe(Temperature)@user Location`, which is a point.

As I mentioned, I have written two expressions: the first for TL, the temperature of the user point, and the second for the heat source, e.g., if(TL1<130, HS1+HS2,if(TL1<=130,HS1+15%*Hs2, HS1 )).
I have tried to define TL as an additional variable, which I then use in the second expression; however, it did not work.

The TL was referenced as an unrecognized name.

what could be the problem?

bests,

[ghorrocks]

You need to define a monitor point called "user Location", or a point source term called "user Location".

[MNMK]

Hi,

I did not understand your meaning. My aim is not to monitor the values. I would like to change my heat source by changing the temperature at a specific location. As you mentioned, I defined a monitor point in Cartesian coordinates: Location x y z, with the output variable Temperature, and I named it Monuser. I also used it in my first expression: TL1 = avg(Temperature)@Monuser. Then, I used it in the second expression to change my heat source value: if(TL1 < 130[C], HS1 + HS2, if(TL1 <= 130[C], HS1 + 15% * HS2, HS1)).

I received the following error:

ERROR
Attempt to evaluate the CEL callback function 'ave'.
Although it is valid to create an expression that
uses such a function, the preprocessor does not support
its evaluation.


????????????

when I am completely wrong on the way please say to me how should I write for my aim a proper one.

bests,

[ghorrocks]

"Monuser" is a point. You cannot take the average of a point, that is why you got the error. You use the TL = probe(T)@Monuser function to get the temperature value at the point and put it in CEL variable TL. You can then use it in any CEL expression.

[MNMK]

The problem is that whether I use an average on a surface or a probe at a point in an expression and then use it in another expression, the error will be the same. (see Attachment)

ERROR
Attempt to evaluate the CEL callback function 'probe'.
Although it is valid to create an expression that
uses such a function, the preprocessor does not support
its evaluation.


?????

wishes

[Gert-Jan]

Looks like the probe for a point doesn't work in the solver. I think it is exclusively meant for CFD-Post.

I know from experience that it is possible to use an inlet temperature that is equal to a certain outlet temperature: Tinlet=areaAve(T)@Outlet. I think you should therefore make a named surface or a control volume in your geometry, mesh it and create the appropriate expressions.

[Opaque]

probe(<Variable>)@<Point Locator> works as followed:

1 - Validated for point locators ONLY. Such points include Source Point and other Monitor Points
2 - Re-validated, and executed during the simulation by the Ansys CFX Solver
3 - executed in CFD-Post if it is part of the EXPRESSIONs section created in the Ansys CFX Pre.

Please post the full set of expressions used.

[MNMK]

Monitor Point: Monuser

FLOW: Flow Analysis 1
OUTPUT CONTROL:
MONITOR OBJECTS:
&replace MONITOR POINT: Monuser
Cartesian Coordinates = 0.077 [m], 0 [m], 0 [m]
Coord Frame = Coord 0
Option = Cartesian Coordinates
Output Variables List = Temperature
MONITOR LOCATION CONTROL:
Interpolation Type = Nearest Vertex
END
POSITION UPDATE FREQUENCY:
Option = Initial Mesh Only
END
END
END
END
END




TL1 Expression:

probe(Temperature)@Monuser

HZ1 Expression:
areaAve(Temperature)@REGION:HZ1

HZ2 Expression:
areaAve(Temperature)@REGION:HZ2

percent Expression:
0.0050*aitern/100

Heat Source Expression:

if(TL1<130[C], HZ1+1*HZ1,if(TL1>=130[C],HZ1+percent*HZ1, HZ1 ))

ERROR
Attempt to evaluate the CEL callback function 'probe'.
Although it is valid to create an expression that
uses such a function, the preprocessor does not support
its evaluation.

[ghorrocks]

When does this error come up? Are you trying to evaluate the expression in CFX-Pre? Or in the solver?

[MNMK]

in cfx-Pre when I try to plot the heat source expression

[ghorrocks]

Of course the probe function does not work in CFX-Pre. It is just the pre-processor, so all the variable arrays have not been set up yet. The probe function takes the value of the array at a defined point, so will only work in the solver or post-processor after those variable arrays are set up in the solver.

[MNMK]

Can you suggest me a Solution?

If it is possible with other function?

[ghorrocks]

Isn't it obvious? You have to run the solver.

[MNMK]

Thank you.

However, it would be better if it were possible to plot the expression before running it.

wishes

[Gert-Jan]

Then define a fluctuating temperature (sinusoidal?) and use that as an example probe. If that works, then probably your control expression will work as well. Provided your example probe is representative for the deviations you expect in your simulation.

BTW, I don't see the variable "time", but "aitern". So you are running steady state?

[MNMK]

Thank you both.

Due to the size of my model, I want to calculate it in steady state first. However, as you have realized, the case should be considered in transien.

I manually calculate how the values change during the calculation process. it look well.


reagrds,

[ghorrocks]

And have a careful think about whether this setup is really steady state at all. How can it be steady state if the source term keeps changing?

[MNMK]

I just want to check the influence of my heat source changing on my outlet temperature.