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

Cavitating liquid jet

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

LinkBack Thread Tools Search this Thread Display Modes
Old   August 11, 2021, 13:18
Default Cavitating liquid jet
New Member
Join Date: Aug 2021
Posts: 5
Rep Power: 2
helena97 is on a distinguished road
I am trying to simulate cavitating liquid jet in student version of Ansys Fluent, see enclosed geometry. The mesh is very dense in the nozzle area.
At first, I set only steady state calculation with one phase, then I switch to multiphase mixture and I run it with its implicit formulation of volume fraction, still at steady state. But as I guess that the cavitating jet is in reality pulsating, I switch to transient calculation afterwards.
I have very small time step (1e-8), 20 iterations per time step and I have reduced relaxation factors to 0.05 for vaporization mass and 0.5 for density. I use realizable k-epsilon model of turbulence with non equilibrium wall functions. For cavitation, I set Schnerr Sauer model with its default settings. I leave densities of water liquid and water vapor as constant.
The problem is that the cavitation starts to disappear after some time and I dont know why. It does not appear again even if I run the calculation for very long time. And also the calculation is very time consuming because of that very small time step.
I enclose also some pictures of the cavitation appearing and disappearing. I don't know whether it disappears because a backwards pressure wave appears. I got some messages on the console that there is reversed flow on outlet. I tried to prolong the outlet but it still disappears.
How would you approach to this problem in general? What would you set? Would you solve it as transient? Would you choose different cavitation models or models of turbulence?
I have also tried to calculate it with energy equation turned on, I had to reduce controls a lot and I set a non reflecting acoustic wave model. The result was that the cavitation was being damped quite a lot and in the end it diverged because of temperature... I am quite lost so I would really welcome some tips.
Thank you in advance.
Attached Images
File Type: jpg mesh.jpg (70.0 KB, 9 views)
File Type: png mesh2.PNG (68.4 KB, 6 views)
File Type: jpg mesh3.jpg (105.3 KB, 6 views)
File Type: jpg animace-faze_3_0002.jpg (106.6 KB, 7 views)
File Type: jpg animace-faze-3_2_0195.jpg (46.9 KB, 8 views)
helena97 is offline   Reply With Quote


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
Free turbulent water jet into liquid metal pool, inlet submerged Estone Fluent Multiphase 1 February 22, 2019 14:39
Modelling of a primary break-up (atomization) of a liquid jet senen OpenFOAM Running, Solving & CFD 0 December 11, 2018 12:33
[swak4Foam] Liquid jet BreakUp length and diameter before it breaks using swak4FOAM rzahoor OpenFOAM Community Contributions 0 December 10, 2016 18:15
simple Liquid jet simulation in an open domain canev.civelek FLUENT 2 May 4, 2014 18:17
Liquid Jet into Supersonic Flow Alex CFX 4 June 20, 2007 11:56

All times are GMT -4. The time now is 16:08.