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Active Contributor
Sultan9009
Posts: 34
Registered: ‎06-19-2012

Steady coupled thermal and fluid flow help

82 Views, 3 Replies
07-31-2012 09:41 AM

I need help with this analysis because every time, I run simulation, the results are always zero for velocity, calculated temperature, and I not getting any results for pressure. I also want to know if I will be able to have the shaft have a constraint of rotated frame. I know the velocity and initial temperature for the inlet but know nothing for the outlet. Can I get some help? I try uploading a ach file, but the file is too big

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INACTIVE_AstroJohn
Posts: 492
Registered: ‎03-25-2010

Re: Steady coupled thermal and fluid flow help

07-31-2012 10:54 AM in reply to: Sultan9009

Hi Sultan,

 

Are you receiving results of 0 at every time step, or are you getting no results because the analysis stopped with an error?

 

If the results are 0 at every time step, the problem is that the loads are 0. So, check the applied loads and the load multipliers under the "Setup > Model Setup > Parameters". (All 3 of the Parameters)

 

If there is an error, you can read it for the Log files shown at the bottom of the Report tree (one log file for fluid flow, one for heat transfer, and one for the coupled.)

 

What I usually do in the case of errors is to change the analysis type to steady state heat transfer (and make a new design scenario at the same time) and see if that runs. If it doesn't, it is usually easier to debug a heat transfer model than a coupled analysis. Likewise, copy the coupled analysis to a new design scenario and set it to steady state fluid flow. Does it run? If not, debug the fluid model.

 

I do not fully understand your description of "the shaft" (what shaft?), but if you have followed the instructions on the Help page "Rotating Frames of Reference", then the answer is yes -- you can do it.

 

Sincerely,
John Holtz, P.E.
Senior User Experience Designer, Simulation
Autodesk, Inc.

Current version of Mechanical & Multiphysics: 2013 SP1 (2013.01.00.0012 28-Jun-2012)
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Active Contributor
Sultan9009
Posts: 34
Registered: ‎06-19-2012

Re: Steady coupled thermal and fluid flow help

07-31-2012 11:03 AM in reply to: Sultan9009

I have designed a water heater. I need to run a thermal and fluid analysis on the water heater. The water heater is driven by a motor through a gear ratio. There is a shaft rotating inside the water heater. It rotating at 1760 rpm. The initial conditons I know is, the initial temperature at inlet which is 30 degree celius. I also know the velocity at the inlet which is 1973.5mm/s. I want to perform, a steady fluid flow, steady thermal flow, and steady coupled fluid and thermal flow analysis. Also, when I am running the fluid flow analysis, I am using the internal volume of the water heater and setting it to water. But I want to use the rotating shaft, which is causing a increase in pressure and velocity of the water inside the water heater, however, I getting illegal elements and it is not meshing because the rotating shaft is not a fluid but a solid. Can you help me?

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Active Contributor
Sultan9009
Posts: 34
Registered: ‎06-19-2012

Re: Steady coupled thermal and fluid flow help

07-31-2012 11:06 AM in reply to: Sultan9009

Also I am getting the results as zero. But I checked and loads are not zero. I put a initial temperature and velocity at the inlet. I know the the conditions of the water, which I consider to be the internal volume. The outer case, I do not know any information. So i placed a 30 degree celius load on the surface of the inlet, and a velocity at the outlet.

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