POPULATION BALANCE MODELING (PBM) in Steady State

osha · July 18, 2015, 19:09

I am simulating separation of 2 different phases of fluid. I am also modelling the coalescence and breakup of bubbles using PBM.

Coalescence and breakup are inherently unsteady phenomenon and I was looking at PBM equations to make sense of coalescence and breakup when treated as steady state.

Most of my simulations in steady state eulerian eulerian multiphase problem with discrete PBM model end up with divergence. But I have been able to stablize the simulation for time being by playing with relaxation factors. The residuals and fluctuations indicates that I am no where close to convergence.

However, I am seeking your opinion and guidance to understand if such multiphase problems with PBM can be treated as steady state?

If yes, how does the results obtained, physically make sense?

Thank you.

cultivate · June 18, 2022, 07:22

hi,osha.I meet the same question:The residuals cannot go down with Iteration in steady simulation? that is to say, convergence is difficult.can you solve the problem?

any help will be appreciated.thank you

July 18, 2015, 19:09	POPULATION BALANCE MODELING (PBM) in Steady State	#1
osha New Member Kalli Join Date: Jul 2014 Posts: 9 Rep Power: 11	I am simulating separation of 2 different phases of fluid. I am also modelling the coalescence and breakup of bubbles using PBM. Coalescence and breakup are inherently unsteady phenomenon and I was looking at PBM equations to make sense of coalescence and breakup when treated as steady state. Most of my simulations in steady state eulerian eulerian multiphase problem with discrete PBM model end up with divergence. But I have been able to stablize the simulation for time being by playing with relaxation factors. The residuals and fluctuations indicates that I am no where close to convergence. However, I am seeking your opinion and guidance to understand if such multiphase problems with PBM can be treated as steady state? If yes, how does the results obtained, physically make sense? Thank you.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Steady state solution as an initial condition for a transient problem	adnanakhtar	FLUENT	7	November 25, 2016 05:16
Steady State solution	ajinkya1	SU2	2	November 26, 2014 04:22
Constant velocity of the material	Sas	CFX	15	July 13, 2010 08:56
regarding steady state discrete phase calculations	hajszan_gyula	FLUENT	1	February 28, 2006 01:32
About the difference between steady and unsteady problems	Lisa	Main CFD Forum	11	July 5, 2000 14:37

June 18, 2022, 07:22		#2
cultivate New Member wu pei peng Join Date: Jul 2021 Posts: 4 Rep Power: 4	hi,osha.I meet the same question:The residuals cannot go down with Iteration in steady simulation? that is to say, convergence is difficult.can you solve the problem? any help will be appreciated.thank you