Consider water flowing through a restriction with a pressure drop of 4 bar. Inlet pressure is 64 bar and the outlet pressure will be 60 bar. A cavitation number, that characterises the potential of the flow to cavitate is give by (p2-pv ) / (0.5 x rho x u x u)(adsbygoogle = window.adsbygoogle || []).push({});

where p2 is the recovered pressure downstream of the restriction which will be 60 bar = 60,000 Pa

PV is the pressure at the vena contracta at the operating temperature, 30 deg C. This pressure is equal to vapor pressure of the water

rho density of water : 998 kg/m3

u : Velocity at the restriction , lets say it is 25 m/s

What should be the Pv here ? still goes by the operating temperature and is regardless of the pressure ?

http://upload.wikimedia.org/wikipedia/commons/0/08/Phase_diagram_of_water.svg

According to this figure the boiling point of water at 60 bar is 275 deg C.

45098 mm hg is the water vapor pressure at 275 deg c

Can someone help me understand to calculating cavitation number here ?

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# What is the cavitation number at the higher pressures ?

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**