Characteristic Velocity

Written by Jerry Ratzlaff on . Posted in Classical Mechanics

Characteristic velocity, abbreviated as U, measure the effectiveness of the combustion of a rocket engine at high temperature and pressure, seperate from nozzle performance.  It is used to compare different propellant and propulsion systems.

 

Characteristic velocity formula

\(\large{ U = \frac { p_c \; A } { \dot m_f }  }\) 

Where:

 Units English Metric
\(\large{ U }\) = characteristic velocity \(\large{\frac{ft}{sec}}\) \(\large{\frac{m}{s}}\)
\(\large{ A }\)  (Greek symbol rho) = area of throat \(\large{ft^2}\) \(\large{m^2}\)
\(\large{ \dot m_f }\) = mass flow rate \(\large{\frac{lbm}{sec}}\) \(\large{\frac{kg}{s}}\)
\(\large{ p_c }\) =  pressure of chamber \(\large{\frac{lbf}{in^2}}\) \(\large{Pa}\)

 

Related Characteristic Velocity formulas

\(\large{ U =  \sqrt{  2  \;  Ec \; c \;  \Delta T     }    }\) (Eckert number)
\(\large{ U =  \sqrt{  \frac{\Delta p}{Eu \;  \rho}  }  }\)  (Euler number

Where:

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

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

\(\large{ Ec }\) = Eckert number

\(\large{ Eu }\) = Euler number

\(\large{ c }\) = specific heat

\(\large{ \Delta T }\) = temperature change

 

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Tags: Equations for Velocity