Advanced concept or meshing problem

Hi friends,

I need a help with my advanced concepts.
the problem here is I gave 50W heat source on the surface of the pipe but the temperature is not high as I like or in experimental data. what did I do wrong?

Hello aburkitbayev

can you please provide us with a link to your project, so that we can have a look at your simulation?

Best regards
Sebastian

how can I provide the link?

how can I provide?

Hello aburkitbayev,
you can send us a link to your project.
Best regards
Sebastian

Arman heat pipe | Automotive | SimScale

problem here is again, when I apply 30W power heat, the temperature should be high. however, it is not? what I have not done correctly? if there is so many mistakes, please let me know

Can you try to set up your project again,
I have tried it myself and git this result, but couldn’t quite figure out what was wrong with your setup.
This is the result I got. Note I used aluminum for all solid parts and air for the fluid but this shouldn’t make any difference in the setpup.

Best regards
Sebastian

if you do not know what is wrong with this, then from whom I can ask a help?

Hello Aburkitbayev,

One thing you may want to try with your simulation is utilizing an “Initial condition” and then set a temperature to whatever you are expecting the pipe to be at, run the simulation, and then seeing what results you get. If your temperature decreases then there is too much heat being removed from you part. A better description of your simulation and what you are trying to accomplish would also be beneficial to answering questions.

Best,
Jake

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Hi Aburkitbayev,
Firstly, I’ve no experience in thermo, but here are my comments & thoughts.
But…maybe I have now found the issue after mapping out the following information. Inlet flow temp set at 20, but fluid water temp set at 24.95 degrees, maybe this is the issue?

Run2 - Model
a) Initial global temp, 20C deg,
b) Inlet Vel temp 20C deg
c) Steel shell
d) Copper central cylinder
e) Fluid, Water 24.95C ref temp

As I interpret simulation visual graphics…

  1. Thematic colours show an inflow water temperature about 19.95 to 20C degrees (less than set temp 24.95 deg C)
  2. On passing the central copper cylinder inflow swirling particle temperature of 20 deg C and rises to approx 20.1 degrees matching the external box temperature of 20.1 degrees.
  3. The central copper cylinder temperature is at 20.5 degrees or slightly higher (~21.52C)

Observations;

  1. The fluid flow should commences at 24.95C as it is introduced into the steel inlet tube, but shows a thematic temperature of approx 20 degrees C at the inlet tube & the entry into the steel box. I would expect the fluid heat to be ‘absorbed’ by the steel wall and central copper cylinder and hence expect the fluid flow temperature to drop, but we are seeing the opposite, a rise in temperature of approx 0.1 degrees C.

  2. The probe point located adjacent to the wall of the cylinder facing the inlet flow is records20 degrees C, which is consistent with the inflow thematic temperature colour, but is less than the fluid temperature set at 24.95

  3. Copper is better at transferring heat than steel, approx. 6 times thermal conductivity higher than steel and possibly the copper is collecting the heat from the inflow fluid better than the steel box as Steel with respect to Copper is an insulator

  4. My concern is the initial inflow fluid temperature is NOT at the set value of 24.95C degrees.

Probe point near central cylinder at 20.15 deg C

Inflow should be 24.95 deg, but shows green ~ 20 deg C

Inlet velocity temp 20C but Fluid water temp at 24.95 deg C, maybe this is the issue?

Let me know how you go,

Chuck Mulder

1 Like

I created internal flow volume and imprint. I believe it is what I need to create for my simulation. What I am trying to see is that how much heat will be removed from heat pipe with applied conditions such as water temperature, pipe surface temperature. I am interested how can I reduce the surface temperature of pipe.

Yes, in your case, I can see that after pipe, air temperature increased a lot. However, in my case, not so much. Yes, we know that it is water, but I believe, there should be at least Temperature difference around minimum 5 C degree.

copper cylinder pipe has 30W heat power, which is high more than 80C degrees. how copper pipe can absorb heat? Opposite, it should increase the temperature. Am I right?

Hi aburkitbayev,

I will be interested to see the final solution to this problem, sorry I missed seeing the Absolute power source of the copper at 30W & wasn’t able to provide an answer.

image

Hi mate,
you can have a look at now my simulation in run 3. it is still the same result.

Hi aburkitbayev,
I had a look at Run3, but I see you are doing what I would do…running a few simulations and changing some of the parameters like velocity etc & reviewing the outputs to derive an understanding of what is happening in the simulations to track the problem down.

I use the particle flow & body set to temp to visualise what is happening.
My range is small 20 to 20.05 Celsius (maybe mesh & simulation run time does not provide this accuracy)
My guess is the fluid which in this case on Run3 is water which should be at 20C is entering the inlet tube then the box between 20.02 & 20C, the fluid approaches the copper heated rod and slightly increases in temp then swirls and drops in temp as it possibly picks up cooling from the external box which is set at 20C and then the fluid exits. at 20 C.

I see you have changed the temp setting as suggested earlier, but this time I couldn’t find anything amiss, but I’m a newbie. I see you are trying one with air as @SBlock suggested as this might provide an insight as the fluid density will be lower and air should I imagine heat up easier then water.

So if I was doing a test, I’d use air, slow the velocity right down and run the simulation for an extend period and instead of steel use an insulated material for the box & tube so that any movement in heat can be observed and the box shell does not influence the result of the heating rod influence on the fluid. Hopefully this would reduce the number of inflences & possibly uncover any model issues.

Sorry, I can’t provide definitive answer, good luck