An introduction and definition of the Cavitation Number.
The Cavitation Number or Cavitation Parameter is a "special edition" of the dimensionless Euler Number.
- The Euler Number - an introduction to and a definition of the Euler Number
The Cavitation Number is useful when analyzing fluid flow dynamics problems where cavitation may occur.
The Cavitation Number can be expressed as
σ = (pr - pv) / (1/2 ρ v2) (1)
σ = Cavitation number
pr = reference pressure (Pa)
pv = vapor pressure of the fluid (Pa)
ρ = density of the fluid (kg/m3)
v = velocity of fluid (m/s)
To prevent cavitation
- avoid low pressure - pressurize supply tanks if necessary
- reduce fluid temperature
- use larger suction pipe diameters - reduce minor losses
- use cavitation resistant materials or coatings
- small amounts of air supplied to the suction system may reduce the amount of cavitation damage
- keep available NPSH well above required NPSH.