Heat Transfer with Air Gap

General discussion about Elmer
Post Reply
Gmontgomery29
Posts: 5
Joined: 22 Mar 2022, 23:25
Antispam: Yes

Heat Transfer with Air Gap

Post by Gmontgomery29 »

I am trying to model a section of a covered conveyor which carries material at high temperature. I want to perform a thermal transient analysis to determine when the material cools to a specified temperature. My concern is the air space above the hot material. It will increase in temperature so a constant ambient temperature is not an appropriate input. I don't know what the air temperature is and don't care. My concern is the material temperature.

A picture of the geometric model is attached.

Please provide any advice you may have.

Thank you.

George
Pictures.pdf
(204.94 KiB) Downloaded 25 times
kevinarden
Posts: 1397
Joined: 25 Jan 2019, 01:28
Antispam: Yes

Re: Heat Transfer with Air Gap

Post by kevinarden »

My initial recommendation would be add the air above the material to the model.
kevinarden
Posts: 1397
Joined: 25 Jan 2019, 01:28
Antispam: Yes

Re: Heat Transfer with Air Gap

Post by kevinarden »

You might study tutorial number 25 for the air part of the analyses. For the material you would only need the heat equation. If you don't care about the flow created in the air, than you could use just the heat equation. In that case the model would just have three materials, the material of interest, air, and the steel cover.
Rich_B
Posts: 123
Joined: 24 Aug 2009, 20:18

Re: Heat Transfer with Air Gap

Post by Rich_B »

Hello,

Can you provide the velocity of the conveyor belt, which will presumably also be the velocity of the material?

Hard to tell from the pictures, but I imagine there is a stainless conveyor belt sliding along inside a stationary stainless box, loaded with the material. Or, is the entire bottom surface meant to be the moving conveyor belt? In the second case, there are probably supporting rollers beneath the conveyor belt that aren't shown.

You may want to add air outside of the stainless box, to carry away the heat by convection, either natural or forced?

Rich.
Gmontgomery29
Posts: 5
Joined: 22 Mar 2022, 23:25
Antispam: Yes

Re: Heat Transfer with Air Gap

Post by Gmontgomery29 »

case.sif
(3.18 KiB) Downloaded 8 times
Thank you everyone for your suggestions.

I have been somewhat successful in the analysis. Now I would like to write out the temperatures to a file. I made an attempt with the Savescalers procedure but no results were saved. I would also like to output the results for a particular body.

Can someone tell me how to do this?

Thank you.


George
case.sif
(3.18 KiB) Downloaded 8 times
block.geo
(3.17 KiB) Downloaded 6 times
kevinarden
Posts: 1397
Joined: 25 Jan 2019, 01:28
Antispam: Yes

Re: Heat Transfer with Air Gap

Post by kevinarden »

https://www.nic.funet.fi/pub/sci/physic ... Manual.pdf
See chapters 48 - 60 for examples
For the Variable you have to have an operator such as min, max, mean, etc.
kevinarden
Posts: 1397
Joined: 25 Jan 2019, 01:28
Antispam: Yes

Re: Heat Transfer with Air Gap

Post by kevinarden »

For body you can use mask name

Variable 1 = Temperature
Operator 1 = body force volume
Mask Name 1 = cooling


Body Force 2
Name = "Cooling"
Heat Source = -10
cooling = Logical True
End
Post Reply