|
[Sponsors] |
March 23, 2017, 04:11 |
phase-fraction equation in multiphase model
|
#1 |
New Member
zhengzongji
Join Date: Feb 2017
Posts: 9
Rep Power: 9 |
hi, Dear foamers
I have just learned phase-fraction equation in two-phase model It is ez to understand: ∂(alpha)+∇·(U·alpha) = 0 but when it turns to multiphase model, I can hardly figure out what the equation will change into. Could anybody gives me some suggestions or gives some links related to this? thanks zzj |
|
March 23, 2017, 11:41 |
|
#2 |
Member
Declan
Join Date: Oct 2016
Location: Ireland
Posts: 40
Rep Power: 9 |
I think it is the same for each of the i phases:
∂(alpha_i)+∇·(U·alpha_i) = 0 |
|
March 24, 2017, 04:00 |
|
#3 | |
Member
Ricky
Join Date: Jul 2014
Location: Germany
Posts: 78
Rep Power: 11 |
Quote:
__________________
If it is easy, then something is fishy! |
||
March 27, 2017, 02:17 |
|
#4 | |
New Member
zhengzongji
Join Date: Feb 2017
Posts: 9
Rep Power: 9 |
Quote:
Dear decah,thanks for your replying. In fact,the code shows that in multiphase mixture model we need to solve a variable named "alphaPhiCorr". but "alphaPhiCorr" need all the phases to solve. (It means we can not solve fraction equation phase by phase) And the fraction equation is: ∂(alpha)+∇·(alphaPhiCorr) = 0.(I get the equation from multiphaseMixture.c) MULES::limit ( 1.0/mesh_.time().deltaT().value(), geometricOneField(), alpha, phi_, alphaPhiCorr, zeroField(), zeroField(), 1, 0, true ); And alphaPhiCorr is solved by each phase,following is the code: alphaPhiCorrs.set ( phasei, new surfaceScalarField ( "phi" + alpha.name() + "Corr", fvc::flux ( phi_, alpha, alphaScheme ) ) ); surfaceScalarField& alphaPhiCorr = alphaPhiCorrs[phasei]; forAllIter(PtrDictionary<phase>, phases_, iter2) { phase& alpha2 = iter2(); if (&alpha2 == &alpha) continue; surfaceScalarField phir(phic*nHatf(alpha, alpha2)); alphaPhiCorr += fvc::flux ( -fvc::flux(-phir, alpha2, alpharScheme), alpha, alpharScheme ); } I do not know what does the alphaPhiCorr mean. May be a mathematical formula can help easier understanding. Last edited by zzj; March 27, 2017 at 03:22. |
||
March 27, 2017, 02:22 |
|
#5 |
New Member
zhengzongji
Join Date: Feb 2017
Posts: 9
Rep Power: 9 |
Dear kera,thanks for your help.
I am reading the essay. I will reply after reading. thanks again. |
|
March 27, 2017, 03:18 |
|
#6 | |
New Member
zhengzongji
Join Date: Feb 2017
Posts: 9
Rep Power: 9 |
Quote:
I have finished reading. Unfortunately,The paper only gives the equation of two phases model, I can hardly figure out the equation in multiphase model. |
||
April 5, 2017, 04:33 |
|
#7 |
New Member
zhengzongji
Join Date: Feb 2017
Posts: 9
Rep Power: 9 |
Finally,I figure out the equations
In fact, Decah's idea is right, we just need to solve each phase. |
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Problem with Temperature and volume fraction diffusion in Lee phase Change Model | rapierrz | OpenFOAM Programming & Development | 3 | June 6, 2020 06:49 |
mass flow in is not equal to mass flow out | saii | CFX | 12 | March 19, 2018 05:21 |
How to access only one phase in multiphase model by UDF | wersoe | Fluent UDF and Scheme Programming | 1 | January 4, 2017 07:11 |
Error in Two phase (condensation) modeling | adilsyyed | CFX | 15 | June 24, 2015 19:42 |
Mixture model Volume fraction equation | me12p1006 | Main CFD Forum | 0 | October 1, 2013 05:37 |