Cavitation Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Cavitation Number

Cavitation number ( \(Ca\) ) (dimensionless number) expresses the relationship between the difference of a local absolute pressure from the vapor pressure and the kinetic energy per volume.

Cavitation Number FORMULA

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

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

Where:

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

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

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

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

\(\large{ v }\) = flow characteristic velocity

Solve for:

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

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

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

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

 

Tags: Equations for Pressure Equations for Pumps