Advice about CEV cavitation model

April 19, 2004, 13:06

Hello everybody,

I'm working on the cavitation modelisation in a pump and so far, I use tascflow 11 and the CEV model. I can show a little vapour cavity but as I push the inlet total pressure down It doesn't converge anymore. If I give you the pump caracteristics can you tell me if my mesh has to be better or if I reached the limit of the model?

I saw in a LHM study that they can't find vapour cavity extending further the hydrofoil mid-chord!! http://lmhwww.epfl.ch/Publications/P...AVIPU_03_5.pdf But in my case I am far from this point.

Anyway, Here is some caracteristics of my pump if you can help me that will be great!

Quantity___Inlet___Outlet___Outlet/Inlet

Mass-flow____5.999E+01____6.024E+01____1.004E+00 Volume-flow____6.024E-02___6.049E-02___1.004E+00 Density____9.959E+02___9.959E+02___1.000E+00

Static-pressure___8.111E+04___2.922E+05___3.602E+00 Absolute-total-pressure___1.024E+05___3.362E+05___3.282E+00

Static-enthalpy___-2.093E+01___2.102E+02__-1.005E+01 Total-enthalpy___5.123E-01___2.544E+02___4.967E+02 Energy___6.171E+03___2.034E+04 3.296E+00

Swirl___3.281E-03___1.664E+00___5.071E+02 Flow-Distortion___1.000E+00___1.017E+00___1.017E+00

Absolute Velocities:

Speed___6.548E+00___9.404E+00___1.436E+00 Radial-velocity ___4.051E-03___4.160E+00___1.027E+03 Tangential-velocity___3.058E-02___8.326E+00___2.723E+02 Axial-velocity___6.548E+00__-1.590E-01__-2.428E-02 Circumferential-velocity__4.467E-02__9.396E+00__2.103E+02 Meridional-velocity__6.548E+00__4.178E+00__6.381E-01 Absolute-flow-angle__2.676E-01__6.335E+01__2.368E+02

Relative Velocities: ------------------- Speed__1.559E+01__2.6E+01__1.473E+00 Tangential-velocity___-1.393E+01__-2.265E+01__1.625E+00 Circumferential-velocity__1.393E+01__2.305E+01__1.654E+00 Relative-flow-angle__6.483E+01__7.955E+01__1.227E+00

OK! I realize that you may not be able to answer my question with this figures only! but if you have some kind of experience about cavitation with Tascflow or some good references about CEV model, I am really looking for advices! thanks for your help! Matthieu

Sachin Zanje · October 27, 2018, 11:00

Hi,
I want to understand about the Mathematical formulation of Constant Enthalpy Vaporization (CEV). Is it possible for you to send me the relevant document to understand about this Mathematical formulation?

April 19, 2004, 13:06	Advice about CEV cavitation model	#1
Matthieu Guest Posts: n/a	Hello everybody, I'm working on the cavitation modelisation in a pump and so far, I use tascflow 11 and the CEV model. I can show a little vapour cavity but as I push the inlet total pressure down It doesn't converge anymore. If I give you the pump caracteristics can you tell me if my mesh has to be better or if I reached the limit of the model? I saw in a LHM study that they can't find vapour cavity extending further the hydrofoil mid-chord!! http://lmhwww.epfl.ch/Publications/P...AVIPU_03_5.pdf But in my case I am far from this point. Anyway, Here is some caracteristics of my pump if you can help me that will be great! Quantity___Inlet___Outlet___Outlet/Inlet Mass-flow____5.999E+01____6.024E+01____1.004E+00 Volume-flow____6.024E-02___6.049E-02___1.004E+00 Density____9.959E+02___9.959E+02___1.000E+00 Static-pressure___8.111E+04___2.922E+05___3.602E+00 Absolute-total-pressure___1.024E+05___3.362E+05___3.282E+00 Static-enthalpy___-2.093E+01___2.102E+02__-1.005E+01 Total-enthalpy___5.123E-01___2.544E+02___4.967E+02 Energy___6.171E+03___2.034E+04 3.296E+00 Swirl___3.281E-03___1.664E+00___5.071E+02 Flow-Distortion___1.000E+00___1.017E+00___1.017E+00 Absolute Velocities: Speed___6.548E+00___9.404E+00___1.436E+00 Radial-velocity ___4.051E-03___4.160E+00___1.027E+03 Tangential-velocity___3.058E-02___8.326E+00___2.723E+02 Axial-velocity___6.548E+00__-1.590E-01__-2.428E-02 Circumferential-velocity__4.467E-02__9.396E+00__2.103E+02 Meridional-velocity__6.548E+00__4.178E+00__6.381E-01 Absolute-flow-angle__2.676E-01__6.335E+01__2.368E+02 Relative Velocities: ------------------- Speed__1.559E+01__2.6E+01__1.473E+00 Tangential-velocity___-1.393E+01__-2.265E+01__1.625E+00 Circumferential-velocity__1.393E+01__2.305E+01__1.654E+00 Relative-flow-angle__6.483E+01__7.955E+01__1.227E+00 OK! I realize that you may not be able to answer my question with this figures only! but if you have some kind of experience about cavitation with Tascflow or some good references about CEV model, I am really looking for advices! thanks for your help! Matthieu

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October 27, 2018, 11:00		#2
Sachin Zanje New Member Maharashtra Join Date: Dec 2017 Posts: 13 Rep Power: 9	Hi, I want to understand about the Mathematical formulation of Constant Enthalpy Vaporization (CEV). Is it possible for you to send me the relevant document to understand about this Mathematical formulation?