Orifice Discharge Coefficient

Written by Jerry Ratzlaff on . Posted in Flow Instrument

Orifice discharge coefficient, abbreviated as $$C_d$$, a dimensionless number, is the ratio of actual discharge to the theoretical discharge.

Orifice Discharge Coefficient formula

 $$\large{ C_d = \frac { Q } { A_o \; \sqrt { 2 \; G \; h } } }$$

Where:

 Units English Metric $$\large{ C_d }$$ = orifice discharge coefficient $$\large{ dimensionless }$$ $$\large{ A_o }$$ = orifice area $$\large{ in^2 }$$ $$\large{ mm^2 }$$ $$\large{ h }$$ = orifice center of head $$\large{ in }$$ $$\large{ mm }$$ $$\large{ Q }$$ = orifice flow rate $$\large{\frac{ft^3}{sec}}$$ $$\large{\frac{m^3}{s}}$$ $$\large{ G }$$ = orifice gravitational constant $$\large{\frac{lbf-ft^2}{lbm^2}}$$ $$\large{\frac{N - m^2}{kg^2}}$$