I would build the pipe, apply the internal fluid pressure as a constant (or vary the internal surfaces and apply piecewise linear pressures), apply the temperature gradient, and then put an external hydrostatic pressure on the top of the pipe giving the fluid density causing the hydrostatic pressure a density equivalent to soil.

Another option is to model the internal pressure as a hydrostatic pressure and then apply a uniform pressure on top of the pipe.

One final option off the top of my head is to build the pipe.  On top of the pipe, build brick elements up to the surface.  Give the brick elements a low modulus or even use 3D kinematic elements so it doesn't try to calculate the stress in them, but give them a density of soil.  If this makes too many elements, cut it short and manipulate the density based on the weight of soil that you need and the volume of brick elements you build.

Garland

Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
Lower Alabama SolidWorks Users Group

Dear Mr.Borowski,

Thank you for your suggestions offered to me . I was very impressed with your web site. It seems to me that your level of expertise is quite advanced.

I am more of a beginer with ALGOR.I had only some experience with Pro/Mechanica and Pro/Engineer. Unfortunately in my office I do not have these softwares available.The only FEA software available in my office is ALGOR.

I am not sure if , by following the details that you have sent to me, I could manage to create a correct model of a buried pipe. Is there any tutorial or worked example for a buried pipe model that you know of? Looking forward to hearing from you.

Regards,

One Point

Thank you for the compliments...I will pass them on to my website builder/business manager.

I may have misunderstood...is this purely for a heat transfer model?  If so, many of the suggestions that I made regarding the pressures is probably not important.  Are you just trying to give an internal temperature and determine the conduction through the pipe and convection into the soil?  If so, this problem becomes a much easier 2-D model that starts with modeling the cross-section of the pipe.

Let me know.

Garland

Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
Lower Alabama SolidWorks Users Group

Dear Mr. Borowski,

Thank you very much for your support. As I have mentioned before, I am not quite knowlegeable with ALGOR capabilities.

Comparing ALGOR with Pro/Engineer I would say that now as I started working with ALGOR, I do like ALGOR much more then PRO/Engineer.

Yes, I am just trying to give an internal temperature and determine the conduction through the pipe and convection/conduction into the soil.

So, is it possible for you to walk me through the necessary steps to model the buried pipe geometry? I have to perform a steady state heat transfer analysis for this buried  and uninsulated pipe at a depth of 1 meter.

Could you please tell me how are going to help me? I look forward to hearing from you.

Once again thanks a lot.

One Point

Best regards,

bogdan_enviro@yahoo.co.uk