Two-phase centrifugal pump design

[LPHS]

Hy,
I am designing a fuel pump for an aircraft engine application. The pump have to function correctly with low pressure inlet condition (Pinlet-PTVP < 0.2bar) and a V/L ( Vapor volume/ liquid volume) of 0.45.
An inducer is used to reduce the V/L.

I have got 2 questions concerning this application:
1- As the fluid density decrease with the V/L, the NPSHA increase...But what is the influence of the V/L on the NPSHR? How can I determinate it?

2- I assume that radial impeller can work with a low V/L condition.
Which V/L is admissible at the impeller inlet?

Thanks for answers!

 

[209larry]

LPHS,

You require multiphase pump of screw type not centrifugal pump. The pump is designed to function as compressor and pump.


Regards,

209larry

 

[LPHS]

Thanks for your answer.

But in our case, a two-phase flow is a very rare functionning point: The centrifugal pump is a better solution.
The requirement of our pump:
speed: around 7500 rpm
flow: near 25000pph
pressure rise: around 145 psid

My question is really: until which Liquid-Vapor ratio a radial impeller can correctly work?