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

[User Defined Scalar in the Eulerian Model

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

LinkBack Thread Tools Search this Thread Display Modes
Old   December 11, 2014, 10:28
Default [User Defined Scalar in the Eulerian Model
New Member
Rafael Cerqueira
Join Date: Mar 2012
Posts: 13
Rep Power: 14
rafacerq is on a distinguished road

I am very used to the VOF model in Fluent.
However, in the past days I decided to simulate a few cases with the Eulerian model.

I'm planning to simulate some sort of bubble column reactor with mass transfer with the aid of two User Defined Scalar, one in the continuous phase and other in the dispersed phase. Something in the line of this work "Mass transfer in bubble columns".

Unfortunately, I had lots of problems with the user-defined scalars.
First, I am not sure how the "mass flow rate" flux function and the "default" unsteady function is modeled when the multiphase eulerian model is activated.
The source of this questioning lies in the fact that the scalar is being advected to cell regions where the phase volume fraction (VOF) is zero.

To illustrate my problem, I set up one-dimensional case to test a user-defined scalar, located in dispersed phase.
In this 1D case i did not added a source term to model the interfacial mass transfer and the spatial discretization used is the first order upwind.

The boundary conditions are:

west: velocity-inlet
- phase-1: u=0.1 m/s; VOF = 0.1; scalar = 1.0
- phase-2: u=0.0 m/s;

east: pressure-outlet

north: simmetry
south: simmetry

The results, from a certain time-step are:



From the two illustrations is possible to see that the UDS scalar field is not being properly advected.

The case file and the 1d mesh are here:

Someone ever encountered this kind of problem?

Best Regards,
Rafael de Cerqueira
rafacerq is offline   Reply With Quote


eulerian, multiphase, uds, user defined scalar

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
UDF to modify the value of a user defined scalar Raja Banerjee Fluent UDF and Scheme Programming 5 March 5, 2019 14:19
Implementation: Break-up model of Coulaloglou and Tavlarides OpenFOAM Programming & Development 7 September 8, 2014 05:43
Overflow Error in Multiphase Modelling with Two Continuous Fluids ashtonJ CFX 6 August 11, 2014 14:32
Water subcooled boiling Attesz CFX 7 January 5, 2013 03:32
Erosion model and Eulerian Model leonozx FLUENT 0 April 7, 2011 05:45

All times are GMT -4. The time now is 16:55.