CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > General Forums > Main CFD Forum

Flow reversal in the sliding mesh of a centrifugal fan

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 20, 2023, 14:26
Default Flow reversal in the sliding mesh of a centrifugal fan
  #1
New Member
 
kartik khanna
Join Date: Feb 2019
Posts: 1
Rep Power: 0
kartikkhanna is on a distinguished road
Hi all,

Can any of you please throw some light on the below results which I have got from the transient analysis of a 3D centrifugal pump (sliding mesh)

So, basically I have created 2 cases which are as follows:
1. Centrifugal fan rotating CCW at 1500 rpm at 24pa Outlet static and 0pa total inlet.
2. Same fan rotating at 400 rpm CCW at 24pa Outlet static and 0pa total inlet.

Below are the plots of velocity vectors' plots obtained for the two results.

1. For 1500 rpm, the plots have been shown for 0.2175s, 3.51s and 6.05s. If you see the plots, you will notice that the flow is reversing back from the outlet back into the rotor and this reverse flow is increasing with time. What do you think the reason might be. I understand that the flow reversal is logical to happen in first few timesteps since the rotation of the rotor might create some negative pressure inside which is filled in by the flow reversal. But why is the flow reversal increasing over time?

2. For 400 rpm, below are the velocity plots at time steps 0.145s and 3.156s. Here also, the trend is same as 1500 rpm.

Can someone please let me know as to what the reason of this increasing flow reversal might be? I have tried running the cases at lower outlet static pressure of 3pa (just to make sure that the higher static pressure isn't causing the flow reversal). But the results have been the same. I can post the solver settings if that is imperative to explain what is happening.

Thanks and Regards
Attached Images
File Type: jpg 400rpm_0.145s.jpg (79.1 KB, 10 views)
File Type: jpg 400rpm_3.51s.jpg (97.8 KB, 9 views)
File Type: jpg 1500rpm_0.2175s.jpg (87.4 KB, 6 views)
File Type: jpg 1500rpm_3.51s.jpg (116.7 KB, 5 views)
File Type: jpg 1500rpm_6.0537s.jpg (87.1 KB, 5 views)
kartikkhanna is offline   Reply With Quote

Reply

Tags
centrifugal fan, cfd - post, reverse flow, sliding mesh, staticpressure


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
3D CFD Sliding Mesh Problem, nodes on the interface side not moving. vaibhavvsr FLUENT 0 March 1, 2023 07:48
Flow around a fan with filter Shoh FLUENT 0 July 24, 2020 13:27
[ICEM] Bad Quality Hybrid Mesh External Flow tim13 ANSYS Meshing & Geometry 0 March 8, 2020 03:22
[mesh manipulation] Importing Multiple Meshes thomasnwalshiii OpenFOAM Meshing & Mesh Conversion 18 December 19, 2015 19:57
Icemcfd 11: Loss of mesh from surface mesh option? Joe CFX 2 March 26, 2007 19:10


All times are GMT -4. The time now is 16:18.