Cavitation Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Cavitation number, abbreviated Ca, is a dimensionless number that expresses the relationship between the difference of a local absolute pressure from the vapor pressure and the kinetic energy per volume.

 

\(\large{ Ca = \frac { 2 \left(p \;-\;p_v \right)   } {\rho U^2}  }\)         

\(\large{Ca = \frac { \left(p \;-\;p_v \right)   } { \frac {1}{2}  \rho U^2}  }\)        

Where:

\(\large{ Ca }\) = Cavitation number

\(\large{ U }\) = characteristic velocity

\(\large{ \rho }\)  (Greek symbol rho) = density of the fluid

\(\large{ p }\) = local pressure

\(\large{ p_v }\) = vapor pressure

Solve for:

\(\large{ p =  \frac {Ca \rho U^2} {2}  \;+\; p_v   }\)

\(\large{ p_v =  p  \;-\;  \frac {Ca \rho U^2} {2}  }\)

\(\large{ \rho =  \frac { 2 \left (p \;-\;p_v \right)}  {Ca U^2}  }\)

\(\large{ v =  \sqrt {      \frac { 2 \left (p \;-\;p_v \right)}  {Ca U^2}      }    }\)

Tags: Equations for Pressure Equations for Pumps