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-   -   VOF Model? (http://www.cfd-online.com/Forums/fluent/28014-vof-model.html)

Adel Ataki November 14, 2000 13:53

VOF Model?
 
Hallo all, I am a new user of FLUENT and need an argent help. my project is a simulation of two phase flow in an equaterial cross section inclined channel. The two phases (Liquid and Gas) are introduced to the channel in a countercurrent modus. The two phases are in contact from the inlet to the outlet (interface area is needed) allI what I know are the gas velocity at the gas-inlet and the liquid velocity at the liquid inlet. Operating conditions are the ambient conditions. I use VOF model, unsteady flow to simulate this problem. My quistions are: 1-What kind of boundary conditions should I choose to solve this problem? 2- if I use the following (what I am trying now): channel inlet (top) - velocity inlet for the liquid with definite inlet-area. -pressure-outlet for the gas the rest of the inlet-area. channel outlet (bottom) -velocity inlet for the gas with a geussed area -outflow for the liquid with a guessed area. Which value shall I give for the Flow Weighting Rate? I have here two phases with two outlets! Is FWR defined here for one phase or for the two pheses? Were shall I define the pressure reference to get a gas flow at the outlet? 3- Waht are the creterions whch say me that the solutions are OK? 4- Does anybody know how can I save Counters ( for Velocity Vectors for example) during the solution under batch betrieb every few time steps?

Thanks for all Adel Ataki

Max November 17, 2000 11:41

Re: VOF Model?
 
first of all, how many inlet do you have?if u only have 1 inlet,then u should set ur boundary condition as velocity inlet since u have inlet velocity.(but i'm not sure the velocity magnitude in the inlet setting of boundary condition in fluent 5 is referred to the air or water velocity).if u have the both velocity and pressure value, then u may choose either velocity inlet or pressure inlet as your inlet boundary condition. if u do not have the value of pressure (either inlet or outlet), u better do not deal with pressure setting(my personnal opinion),u better set outflow as your outlet.If u only have 1 outlet, then the FRW is 1.if u have 2 outlet & wish to divid your outflow equally,then u may set FRW as 0.5 for each one. if u want 30% outflow go out from outlet 1,then set FRW for outlet 1 as 0.3 & FRW for outlet 2 as 0.7..Is that clear?

Max

Adel Ataki November 22, 2000 06:24

Re: VOF Model?
 
thank you Max!


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