|May 7, 2012, 12:56||
Laminar-turbulent slope change in heat transfer
Join Date: Dec 2011
Location: Madrid, Spain
Posts: 134Rep Power: 7
Hello everyone, I hope you guys can give me a hand about the next question:
I have calculated the heat transfer rate to the walls from hot fluid along a pipe typical of a heat exchanger (the walls have some turbulence promoters). The CFD code I am using is Ansys CFX.
I did this for several Reynolds numbers in the laminar range (Re=100-3000), I used no turbulence model here. Then I went into the turbulent range (Re=2000-30000) using the SST model.
Finally I plotted an averaged Nusselt number over the walls surface vs inlet Reynolds number. Contrarily to what I was expecting, I did not observe a change in slope in the Nusselt number for the two ranges considered. I was expecting to get a steeper slope in the turbulent region, as turbulence is supposed to enhance heat transfer.
Do you guys have any idea as to why I am not getting this slope change? Just to clarify, I am not trying to predict laminar-turbulent transition, since I guess this is far beyond this code capabilities.
Alright, thanks a lot for your help.
|Thread||Thread Starter||Forum||Replies||Last Post|
|Heat Flux at wall in a conjugate heat transfer problem||Chander||CFX||2||July 9, 2011 22:22|
|No results for solid domain||Gary Holland||CFX||10||March 13, 2009 04:30|
|Natural convection - Inlet boundary condition||max91||CFX||1||July 29, 2008 20:28|
|Turbulent heat transfer calculation||Frank Rubensdorffer||FLUENT||2||May 29, 2002 14:37|
|Heat transfer coefficent in turbulent flow||Ola Lindgren||Main CFD Forum||2||November 17, 1998 06:49|