# Multiphase solid-liquid flow Lagrangian approach

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

 June 12, 2020, 17:59 Multiphase solid-liquid flow Lagrangian approach #1 New Member   AJ Join Date: Feb 2020 Location: United Kingdom Posts: 20 Rep Power: 6 Hello I am trying multiphase simulation using a Lagrangian approach. I am using 288 mm stirred tank with baffles and pitch blade impeller. I use 10 per cent volume of glass beads and 90 per cent water. I inject 1000 glass particle out of 10 per cent and simulate them. So I have to set the volume fraction of solid particle and water. Since I use 1000 particles out 10 per cent, I can not use 0.1 and 0.9 volume fraction for solid phase and liquid. I can calculate the total volume of 1000 glass beads (v1), but u don't know how to convert that v1 to volume fraction because I don't know the exact volume of the stirred tank, because it includes baffles, shaft, impeller. So is there any way to get the exact volume of the tank in cfx or how can I set volume fraction of solid particles excluding that 1000 particles. Or is there any way to set that out of 0.1 volume fraction of solid particle I can use X volume fraction (equivalent to 1000 particle) for injection. Thank you Anand Last edited by ajjadhav; June 14, 2020 at 07:16.

 June 13, 2020, 05:46 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,728 Rep Power: 143 Your question started well, but headed off into XY problem land after a while (http://xyproblem.info/)..... Your problem has nothing to do with the volume of the tank or scaling the volume fraction to account for the 1000 particles. Your problem is you have not read the CFX documentation so you know how lagrangian particle tracking simulations work In CFX, the tracked particles each represent a large number of particles. Say there is actually 10 million particles in your case, and you are modelling it with 1000 particles. CFX automatically then models those particles so each particle has the effect of 10000 actual particles. So each modelled particle is representative of 10000 actual particles. This means the full volume fraction, interphase drag and other effects are modelled, despite only a fraction of the actual particle number being modelled. But the most important thing for you to do is to read the CFX documentation. You need to understand a model if you are going to use it. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

 Tags cfx, lagrangian, particle tracking