Orifice Area

Written by Jerry Ratzlaff on . Posted in Flow Instrument

  • orifice liquid 1Geometric orifice area (GOA) is the orifice opening
  • Effective orifice area (EOA) is the minimal cross-section area of the downstream jet.
  • Contraction coefficient (\(C_c\)) is the ratio of the area measured at the vena contracta (EOA), to the area of the orifice (GOA) or \(C_c = \frac{EOA}{GOA}\)
  • Discharge coefficient (\(C_d\)) is the ratio of actual flow to ideal flow or \(C_d = \frac{Q_a}{Q_i}\)


Orifice Area formula

\(\large{ A_0 =  \frac{ Q  }{ C_d \; \sqrt{ 2 \; g \; H }  }   }\)   


\(\large{ A_o }\) = orifice area

\(\large{ h }\) = orifice center of head

\(\large{ C_d }\) = orifice discharge coefficient

\(\large{ Q }\) = orifice flow rate

\(\large{ G }\) = orifice gravitational constant



Tags: Equations for Area Equations for Orifice and Nozzle