×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Uncoupled heat transfer analysis

Uncoupled heat transfer analysis

Uncoupled heat transfer analysis

(OP)
I have a pipe that the product inside is 60oC. half of the pipe is in the water which is 4oC. and half in in the air which is 22oC.

How should I apply the boundary condition to the 3 surface of the pipe (inside pipe, outer pipe in water, outer pipe in air)? in order to output the temperture within the pipe for the stress analysis.

should I apply  by BC - surrounding temperture?
                or Load - surface heat flux?

If I need to apply as surface heat flux, how can I calculate it please?

RE: Uncoupled heat transfer analysis

You apply Temperature BC at the outer surface of the pipe contacting the water (that is the temperature of the water [we assume it fixed])and the Temperature BC at the outer surface of the pipe contacting the Air (that is the temperature of the air [we assume it fixed])and given the thermal properties of the pipe, the temperature and the flux at any point in the pipe (including the inner surface) will be calculated.

RE: Uncoupled heat transfer analysis

Inside the pipe you'd calculate the heat transfer coefficeint to the medium inside depending on its flow rate and so forth. On the outside I'd set the temperature to the water temperature too, but to the air you have natural convection (from a vertical surface presumably) and radiation to the ambient. It's not a fixed temperature as Cansand says.

corus

RE: Uncoupled heat transfer analysis

(OP)
The pipe that in the air ios enclosed within a bigger pipe that the outer pipe is in the water.
If I have to consider flow rate inside the pipe, why do i not needed for the water?
If I samplifer the problem by applying temperture to the surface that touch the water and the inner pipe that touch the product. How wrong is my results (assuming the maximum temperture different is only 60oC)

RE: Uncoupled heat transfer analysis

If the pipe is stood in water that is stagnant then it's reasonable to assume that the pipe outer surface is at the water temperature. If the water is moving due to some convection processs then you might have to calculate a heat transfer coefficient. If the pipe is inside of another pipe then you'd have to consider radiation from one pipe to the other, whilst the outer pipe radiates to the ambient.
If you're not sure then take the worst case possible for maximum stress. In this case that would be maximum temperature differences either through the thickness or mean temperature differences. If your stresses are acceptable for the worst case then a lesser more realistic but unkown case, would also be acceptable too.

corus

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close