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Heating with on-off heating pens

Posted Feb 28, 2012, 9:24 a.m. EST Heat Transfer & Phase Change Version 4.2a 3 Replies

Hans Parmentier
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I have a plate with 8 heating pens inside. All off them having a same power.

I already did a lot of simulations in order to see how high the power level is to be set.

Now I want to take my model a step further.
As I have convective cooling I have a large differences between temperatures.
In reality the heating pens are not working when a set point is reached in a thermo couple (8 different thermo couples).

So what I did:
I took a piecewise function and let the power be a function of the temperature.
How can I tell this function to be the Temperature of a Point probe?
(I started with a more primitive design to increase calculation speed but this is taking very much time already (very small time steps))

But it is more difficult to simulate the bandwith.

During heating the heating pens may give power untill 5°C above the setpoint.
Then no power must be added until the temperature is 5°C below the setpoint.
I can make it with step function on a fixed point but not with a bandwith.

Thanks in advance
3 Replies Last Post Feb 29, 2012, 3:30 a.m. EST
Hans Parmentier
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Posted: 1 decade ago Feb 29, 2012, 2:59 a.m. EST
I managed to work around half.

I took a boundary probe and let this probe take the average of the temperature of a side wall.
This temperature could be taken into a function in a variable:
if(bnd1>=330,0,2000)

this is given the process I want to simulate.

But still some open questions I want to have the temperature measured in a point (because I will make 8 temperature measurements for the 8 different heating pens).

And I want to have a bandwith for turning on and of the power.

If I do the same with a point probe I got the following error.

Extrusion coupling operator interpolation failed for at least one point: no source point found.
- Geometry: 1
- Domain: 2
- Destination coordinates.: [0; 100; 100], [0; 100; 100], [0; 100; 100], [0; 100; 100], [0; 100; 100], ...
Failed to evaluate expression.
- Expression: mod1.pdom1(mod1.T)
Failed to evaluate variable.
- Variable: mod1.ppb1
- Defined as: mod1.pdom1(mod1.T)
Failed to evaluate operator Jacobian.
- Operator: if
- Geometry: 1
- Domain: 2


I managed to work around half. I took a boundary probe and let this probe take the average of the temperature of a side wall. This temperature could be taken into a function in a variable: if(bnd1>=330,0,2000) this is given the process I want to simulate. But still some open questions I want to have the temperature measured in a point (because I will make 8 temperature measurements for the 8 different heating pens). And I want to have a bandwith for turning on and of the power. If I do the same with a point probe I got the following error. Extrusion coupling operator interpolation failed for at least one point: no source point found. - Geometry: 1 - Domain: 2 - Destination coordinates.: [0; 100; 100], [0; 100; 100], [0; 100; 100], [0; 100; 100], [0; 100; 100], ... Failed to evaluate expression. - Expression: mod1.pdom1(mod1.T) Failed to evaluate variable. - Variable: mod1.ppb1 - Defined as: mod1.pdom1(mod1.T) Failed to evaluate operator Jacobian. - Operator: if - Geometry: 1 - Domain: 2
Hans Parmentier
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Posted: 1 decade ago Feb 29, 2012, 3:28 a.m. EST
point probe seems not to be working?

with a thermocouple build in as a cilinder it works.

now still looking for the band with
point probe seems not to be working? with a thermocouple build in as a cilinder it works. now still looking for the band with
Hans Parmentier
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Posted: 1 decade ago Feb 29, 2012, 3:30 a.m. EST
point probe seems not to be working?

with a thermocouple build in as a cilinder it works.

now still looking for the band with
point probe seems not to be working? with a thermocouple build in as a cilinder it works. now still looking for the band with

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