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October 5, 2022, 05:12 |
Cavitiy Length for NPSHi calculation
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#1 |
Senior Member
Daniel
Join Date: Feb 2017
Location: Germany
Posts: 167
Rep Power: 9 |
Hello,
is there a way to calculate the cavity length in a pump simulation with the cavitation model ? I would even like to stop the solver when a certain cavity length has been reached, so I can calculate the NPSHi for a given flow. I tried to work with IsoClips in CFD Post and use the length expression, but that is not very clear to me, wether this is a correct or suitable approach. Has anybody done this before ? Thank you your help! Daniel |
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October 8, 2022, 05:14 |
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#2 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,845
Rep Power: 144 |
If you define an isosurface of volume fraction you can get the volume which has gone to vapour. But you will need to define how you want to convert that volume to a length - possible approaches could be maximum extent in x, y z, or a specific direction; longest extent; cube root of the volume - or maybe some other definition is suitable for your case.
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October 10, 2022, 03:44 |
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#3 |
Senior Member
Daniel
Join Date: Feb 2017
Location: Germany
Posts: 167
Rep Power: 9 |
Thank you, Glenn!
Indeed it worked with the Volume Fraction. I created a polyline on the hub and shroud (later additional lines from hub to shroud) and plotted the "Curve Length" of that polyline and calcualted the length where the volume fraction is greater than zero. |
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