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

Modeling a cross flow in a staggered tube bundle using ANSYS CFX

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 16, 2012, 11:42
Default Modeling a cross flow in a staggered tube bundle using ANSYS CFX
  #1
New Member
 
ASHRAF ALFANDI
Join Date: Oct 2012
Posts: 17
Rep Power: 13
ashraf88 is on a distinguished road
Hi every one,

Task: Modeling a cross flow in a staggered tube bundle using ANSYS CFX.

Given: The fluid is water of 300 deg Clausius flowing with inlet velocity 1 m/s,the boundary conditions are defined very well.

Problem: The results shows that water temperature is not changing along the domain; water temp. inlet same as outlet.

So I am not sure about the reason of that, Turbulence model, or water velocity, Heat transfer mode ( Total energy or Thermal Energy) ?

Please help me .
ashraf88 is offline   Reply With Quote

Old   December 16, 2012, 17:29
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,655
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
First of all, please do not hijack threads. Start a new thread for a new question - especially when your question is not related to the original thread.

This problem could be caused by many things - it could be inaccuracy in your simulation (see http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F for tips) or it could be that the setup you are modelling does not result in significant heat being transferred to the water. From the sketchy details you have posted I cannot tell.

Also - are you sure you are using a thermal model? You would not get any heat transfer if you have not enabled thermal modelling. Also how have you modelled the tube bank?
ghorrocks is offline   Reply With Quote

Old   December 16, 2012, 22:21
Default
  #3
New Member
 
ASHRAF ALFANDI
Join Date: Oct 2012
Posts: 17
Rep Power: 13
ashraf88 is on a distinguished road
Quote:
Originally Posted by ghorrocks View Post
First of all, please do not hijack threads. Start a new thread for a new question - especially when your question is not related to the original thread.

This problem could be caused by many things - it could be inaccuracy in your simulation (see http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F for tips) or it could be that the setup you are modelling does not result in significant heat being transferred to the water. From the sketchy details you have posted I cannot tell.

Also - are you sure you are using a thermal model? You would not get any heat transfer if you have not enabled thermal modelling. Also how have you modelled the tube bank?
Dear ghorrocks,
I really appreciate your replay, I am so sorry that i didn't started a new thread.
I am sure that I am using the thermal modeling. But what I am not sure about is that may be I didn't make the setup well.
The tube bank is modeled as a cylinders, not Conjugate heat transfer
Thanks so much for your kind response
ashraf88 is offline   Reply With Quote

Old   December 16, 2012, 22:27
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,655
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
Can you post an image? Also your CCL would help.
ghorrocks is offline   Reply With Quote

Old   January 26, 2021, 02:28
Default Simulation of Convection heat transfer from tube banks in crossflow
  #5
New Member
 
Join Date: Jun 2019
Posts: 5
Rep Power: 6
Mr Torabi is on a distinguished road
Hello everybody
I want to do a simulation of a turbulent cross flow over a inline tube bank with ansys CFX. my material is a mixture of ideal gases(H2O & CO2 & N2). after simulation, results show me that dynamic viscosity and thermal conductivity don't change with temprature even when the tubes temperature have magnificent difference with inflow temperature.
in fact at any temperature:

massFlowAve (Thermal Conductivity)@ Inlet= massFlowAve (Thermal Conductivity)@Outlet

and


massFlowAve(Dynamic Viscosity)@ Inlet= massFlowAve(Dynamic Viscosity)@Outlet


in material section , i select the " Fixed composition mixture" for option part and "Gas phase combustion" for material groups.

key features are
- 2D-channel
- symmetry BC at all walls besides inlet, outlet and tube walls (no-slip walls)
- Thermal energy for heat transfer option
- steady-state

I would be very grateful for every hint, where the error might be. If you need more informations just tell me.

Thanks
Mr Torabi is offline   Reply With Quote

Old   January 26, 2021, 15:10
Default
  #6
Senior Member
 
Erik
Join Date: Feb 2011
Location: Earth (Land portion)
Posts: 1,162
Rep Power: 23
evcelica is on a distinguished road
Well, I would guess that the materials in your mixture all have constant values for thermal conductivity and viscosity by default. You would have to change them to be temperature dependent if you want your mixture to also have temperature dependent properties.
Check the material properties.
evcelica is offline   Reply With Quote

Old   January 27, 2021, 03:30
Thumbs up
  #7
New Member
 
Join Date: Jun 2019
Posts: 5
Rep Power: 6
Mr Torabi is on a distinguished road
Quote:
Originally Posted by evcelica View Post
Well, I would guess that the materials in your mixture all have constant values for thermal conductivity and viscosity by default. You would have to change them to be temperature dependent if you want your mixture to also have temperature dependent properties.
Check the material properties.
yeah. the properties of components were constant and didn't change with temperature. i fixed it

thanks for your hint
Mr Torabi is offline   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
Total Energy -thermal energy Herold CFX 8 April 7, 2017 06:07
Multiphase flow modeling: CFX or FLUENT? Paul Main CFD Forum 8 January 24, 2012 10:25
ANSYS to acquire CFX Fred FLUENT 0 February 18, 2003 22:04
Hydrostatic pressure in 2-phase flow modeling (CFX4.2) HB &DS CFX 0 January 9, 2000 14:19
Hydrostatic pressure in 2-phase flow modeling (long) DS & HB Main CFD Forum 0 January 8, 2000 16:00


All times are GMT -4. The time now is 00:56.