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

\( Cavitation \; number  \;=\;   \frac { 2 \; \left( \; local \; pressure  \;-\;  vapor \; pressure \; \right)   } {  density \;\;x\;\;  characteristic \; velocity^2 }\)

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

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

Where:

\(Ca\) = Cavitation number

\(p\) = local pressure

\(p_v\) = fluid vapor pressure

\(\rho\) (Greek symbol rho) = fluid density

\(v\) = flow characteristic velocity

Solve for:

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

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

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

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

 

Tags: Equations for Pressure Equations for Pumps