Orifice Area
Geometric 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
\(\large{ A_0 = \frac{ Q }{ C_d \; \sqrt{ 2 \; g \; H } } }\) |
Where:
Units | English | Metric |
\(\large{ A_o }\) = orifice area | \(\large{ in^2 }\) | \(\large{ mm^2 }\) |
\(\large{ h }\) = orifice center of head | \(\large{ in }\) | \(\large{ mm }\) |
\(\large{ C_d }\) = orifice discharge coefficient | \(\large{ dimensionless }\) | |
\(\large{ Q }\) = orifice flow rate | \(\large{\frac{ft^3}{sec}}\) | \(\large{\frac{m^3}{s}}\) |
\(\large{ G }\) = orifice gravitational constant | \(\large{\frac{lbf-ft^2}{lbm^2}}\) | \(\large{\frac{N - m^2}{kg^2}}\) |
Solve for:
\(\large{ C_d = \frac { Q } { A_o \; \sqrt { 2 \; G \; h } } }\) |