CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

Heat transfer coefficient in regenerator

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

LinkBack Thread Tools Search this Thread Display Modes
Old   May 26, 2018, 01:23
Default Heat transfer coefficient in regenerator
gartz89's Avatar
Angel Penev
Join Date: Apr 2016
Location: Bulgaria
Posts: 47
Rep Power: 10
gartz89 is on a distinguished road
Hello everyone, I'll show you my model for my thesis and I would like to analysis some details for the conjugate heat transfer (CHT), especially the heat transfer coefficient (h) and Nusselt number (Nu).
So, I've got reversed fixed-matrix regenerator who has following assumptions and BC:
1)There are 2 domains - 1 solid domain - ceramic material and 1 fluid domain - air. I've got couple mesh interface for CHT, and there is heat transfer between solid and fluid domain;
2) The regenerator operates under transient flow or quasi-steady-state connditions (i.e., having constant mass flow rate and inlet temperature);
3) Heat loss to or heat gain from the surroundings is negligible so for BC my walls of the solid domain are adiabatic - the heat flux q = 0 W/m2;
4) The inlet velocity and temperature are uniform over the flow cross section and constant with time, therefore I use velocity inlet for BC;
5) The outlet BC I set pressure outlet;
6) The Initial conditions for the model are initial temperature of the solid domain so I patch the temperature in Solution Initialization;
7)I setting up k-epsilon turbulence model;
8) So I solved the model for 1000 iterations, number of time steps 100 and time step size 0.6 s;
9) After that when I've got this calculations I save my results, and I made duplicate for my model in workbench, because I have to calculate the reverse flow i.e. I use my calculation from last model to create new reverse model from Calculation activities - Automatically Initialize and modify case I open my last calculation file .dat.gz.;
10) For the reversed model my inlet become outlet and my outlet become inlet and the parameters are similar.
Everything looks good and similar with my experimental data in my prototype, but when I compare the heat transfer coefficient in Ansys Fluent and my experiment, the software give me absurd results. When I report in surface integrals -> wall fluxes I have two options to use "Surface heat transfer coefficient" or "Wall function heat transfer coefficient" for the both gives me some error from my experimental date. So I would like to know what is the difference between these coefficients how they are solved in Fluent.
I apologize for my English and I'll be glad somebody to reply of my problem, Thanks a lot!
gartz89 is offline   Reply With Quote


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
Interphase mass transfer of a reaction cfx_ws1992 Main CFD Forum 0 May 15, 2017 21:42
Surface Heat Transfer Coefficient CFD Post MJ1105 Visualization & Post-Processing 0 February 19, 2016 04:57
Ansys CFX problem: unexpected very high temperatures in premix laminar combustion faizan_habib7 CFX 4 February 1, 2016 17:00
Heat Transfer Coefficient in Compressible Flow 3D turbine cascade Karkoura CFX 0 March 10, 2011 15:35
Constant velocity of the material Sas CFX 15 July 13, 2010 08:56

All times are GMT -4. The time now is 00:44.