CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Siemens

Heat transfer tube

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 10, 2003, 12:53
Default Heat transfer tube
  #1
Takeshi
Guest
 
Posts: n/a
I'd like to know an appropriate turbulent model for analysis of heat transfer tube used for heat exchanger. I'd like to know following characteristics.

Pressure drop, Heat transfer coefficient

The size of the tube is as follows:

Inner diameter: 2mm, Length: 500mm

The tube is very slim and long. I have to pay attention to cell size. Too small size cells can make analysis unstable? The tube may be dimpled to increase heat transfer coefficient. Wall temperature is fixed and fluid is water.

What do you think is the most appropriate turbulent model for this analysis? In my opinion, low Re k-e model may be appropriate because I need to cauculate near wall region with high accuracy to evaluate heat transfer coefficient.

Takeshi
  Reply With Quote

Old   July 11, 2003, 10:08
Default Re: Heat transfer tube
  #2
allan
Guest
 
Posts: n/a
regarding the low Re turbulence model, stictly speaking you will need a lot of cells, 20 node points in the boundary layer, however there is alterative, the hybrid wall function where the standard u+ y+ correlation is extended down to y+ approx = 1. This can be activated by setting c125=1, and you must select a low re turbulence model, but use a high re grid.

I found this in various release patches of star, but not in v3150A. If it's not there request a version from CD

Allan
  Reply With Quote

Old   July 14, 2003, 12:29
Default Re: Heat transfer tube
  #3
Takeshi
Guest
 
Posts: n/a
Thank you for your advise. What is c125=1?
  Reply With Quote

Old   July 14, 2003, 13:36
Default Re: Heat transfer tube
  #4
allan
Guest
 
Posts: n/a
c125 and others are control constants which allows beta features and other special controls to be set.

c125 is the one to switch on the hybrid wall functions. On the command line type:

rcon,125,1 and to deselect it

rcon,125,0

allan
  Reply With Quote

Old   July 15, 2003, 10:44
Default Re: Heat transfer tube
  #5
Takeshi
Guest
 
Posts: n/a
Thanks! I'll give it a try.
  Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tube in Tube heat exchanger( But I got error) Young CFX 2 September 26, 2008 01:35
CONDENSATION in a fin-and-tube heat exchanger Rafa FLUENT 3 December 17, 2007 04:28
Heat transfer in helically tube nicolas FLUENT 1 September 17, 2007 10:45
Heat transfer in tube bank. Paul FLUENT 0 August 6, 2004 10:05
a laminar circular-tube heat transfer problem majestywzh FLUENT 1 April 28, 2003 05:59


All times are GMT -4. The time now is 17:31.