Power Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Power Number

Power number ( \(N_p\) ) (dimensionless number) is proportional to drag force and inertial force and is used in momentum transfer and power consumption by fans, mixers and pump impellers at a specified rotational speed.

Power Number FORMULA

\(\large{ N_p = \frac {k_dP}  {N^3\rho l^5} }\)         

Where:

\(\large{ N_p }\) = Power number

\(\large{ k_d }\) =  dimensional constant

\(\large{ P }\) = power

\(\large{ N }\) = rate of rotation

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

\(\large{ l }\) = characteristic length

 

Tags: Equations for Power