Error: Steady coupled fluid flow heat analysis

[tubbl]

I am trying to run a simulation on a heated pipe with flowing water to learn the basics.  The model is a hollow cylinder for the pipe and a solid cylinder inside the hollow cylinder for the water.  

I have applied the inlet and outlet for the water, applied an initial temperature of 70 F for the inlet of the water, and applied a controlled temperature on the outside surface of the pipe.

The simulation fails to run, giving this error:

Autodesk (R) Simulation Steady Coupled Fluid Flow and Thermal Analyses

Version 2012.00a-WIN 04-Mar-2011

Copyright (c) 2011, Autodesk, Inc. All rights reserved.

DATE: October 11, 2011

TIME: 08:57:43 PM

INPUT MODELS:

c:\users\levi\desktop\heat-flow test.ds_data\1\ds

****

**** Iteration starts for velocity and temperature updates

****

**** Error: Temperature update failed. Quit.

In the summary file it says "All temperatures equal 0. Check that loads are applied."

I have applied a default node temperature of 70 F.  I am assuming I am missing a BC but I cannot find what it is.  Can anyone help me with this?

[hupn]

Hi,

For fluid/thermal coupling analysis, both thermal and fluid solvers are involved. The error information most likely say that the thermal solver found some modeling issues. You mentioned that

"I have applied the inlet and outlet for the water, applied an initial temperature of 70 F for the inlet of the water, and applied a controlled temperature on the outside surface of the pipe."

There are possibly some issues there. First for fluid flow, did you just define inlet/outlet boundary condition? You may need prescribed velocity for inlet part. And I think you may really mean to define applied temperature for the inlet part instead of the initial temperature. Can you also give more detail the way you define the controlled temperature on the outside surface? And for Autodesk heat transfer simulation, there are two loading concepts "Applied temperature" and "Temperature". There are probably some confusion for them. I attached the wiki help for your reference.

http://wikihelp.autodesk.com/Autodesk_Simulation/enu/2012/Help/0220-Setting_220/0289-Setting_289/039...

http://wikihelp.autodesk.com/Autodesk_Simulation/enu/2012/Help/0220-Setting_220/0289-Setting_289/039...

hup

[Joey.X]

This may be related to multiples reasons. Here are the check list to narrow down the root.

- All log files including meshing log, preprocess log files, fluid and thermal analysis log files 

- All  fluid and thermal boundary conditions

- Try transient fluid/thermal analysis to see if the problem persist. 

For small model, could you upload the model? 

[tubbl]

Thank you for your response.

I realized the temperatures I was placing on the parts were only on surfaces.  Instead I placed them on the individual parts and the study was able to run.  I placed a 70 F temperature on the fluid and 70 F temperature on the pipe.  I also placed a 300 F applied temperature on the pipe because as I understand it the applied temperature will contribute to heating the water up.  I did place a velocity of 60 in/s into the water.  The problem now is that I get a complete temperature distribution of 300 F across the entire volume of both parts.  I do not think this is correct.  It should have a temperature gradient right?

I attached the .fem file with the results.

[tubbl]

I apologize I realize I have not been very clear.  I am trying to simulate 70 F water flow through a pipe that has a 300 F applied temperature.  I am essentially trying to obtain the temperature of the water as it exits the pipe.  At this point I just need to know how to designate that the temperature of the entering water is 70 F, and thus get a result from the analysis of what temperature the water will be at the exit.

Thank you

[Joey.X]

attached zip has .fem file only, could you zip the whole model and upload?