Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Temperature change from expansion of air

Please login with a confirmed email address before reporting spam

I am trying to model the flow fields of a fluid (air) traveling through an orifice. I have a working model that works great using only the laminar flow module. However, the viscosity of the fluid is always constant as there is no temperature change. So, I want the model to also calculate the temperature change due to the compression of the fluid in the nozzle and then the expansion of the gas following the nozzle. Is there a simple physics to add that will include this temperature change? I would like somthing similar to the high-mach-number flow physics, but without having to use this module as the Mach number does not get above ~0.3. Any help would be great.

3 Replies Last Post 2014年1月17日 GMT-5 11:47
Niklas Rom COMSOL Employee

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2013年4月9日 GMT-4 04:22
Use "Nonisothermal flow".
Niklas

I am trying to model the flow fields of a fluid (air) traveling through an orifice. I have a working model that works great using only the laminar flow module. However, the viscosity of the fluid is always constant as there is no temperature change. So, I want the model to also calculate the temperature change due to the compression of the fluid in the nozzle and then the expansion of the gas following the nozzle. Is there a simple physics to add that will include this temperature change? I would like somthing similar to the high-mach-number flow physics, but without having to use this module as the Mach number does not get above ~0.3. Any help would be great.


Use "Nonisothermal flow". Niklas [QUOTE] I am trying to model the flow fields of a fluid (air) traveling through an orifice. I have a working model that works great using only the laminar flow module. However, the viscosity of the fluid is always constant as there is no temperature change. So, I want the model to also calculate the temperature change due to the compression of the fluid in the nozzle and then the expansion of the gas following the nozzle. Is there a simple physics to add that will include this temperature change? I would like somthing similar to the high-mach-number flow physics, but without having to use this module as the Mach number does not get above ~0.3. Any help would be great. [/QUOTE]

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2013年4月9日 GMT-4 12:58
Thank you for the reply. I tried this method, and I get the same temperature across the entire geometry. As there is no outside heat source/sink.
Thank you for the reply. I tried this method, and I get the same temperature across the entire geometry. As there is no outside heat source/sink.

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2014年1月17日 GMT-5 11:47
So this thread was unsolved?

I am experiencing the same problem, only I am modelling water flow under very high pressure through an orifice, and wnat to model the expected Joule-Thompson heating that occurs.
Like Adam Bateman, I am using the nitf module.
There appears to be no statement of the JT Coefficient in the material properties.

What is the answer???


Thank you for the reply. I tried this method, and I get the same temperature across the entire geometry. As there is no outside heat source/sink.





--

So this thread was unsolved? I am experiencing the same problem, only I am modelling water flow under very high pressure through an orifice, and wnat to model the expected Joule-Thompson heating that occurs. Like Adam Bateman, I am using the nitf module. There appears to be no statement of the JT Coefficient in the material properties. What is the answer??? [QUOTE] Thank you for the reply. I tried this method, and I get the same temperature across the entire geometry. As there is no outside heat source/sink. [/QUOTE] --

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.