Orifice area refers to the area cross-section of an orifice, which is a small opening or hole through which fluid flows. The orifice area is an important parameter in fluid dynamics and flow calculations, particularly in applications such as pipes, nozzles, and valves.
- Geometric Orifice Area (GOA) - The orifice opening
- Effective Orifice Area (EOA) - The minimal cross-section area of the downstream jet.
- Contraction Coefficient (\(C_c\)) - The ratio of the area measured at the vena contracta (EOA), to the area of the orifice (GOA) or \(C_c = EOA \;/\; GOA\)
- Discharge Coefficient (\(C_d\)) - The ratio of actual flow to ideal flow or \(C_d = Q_a \;/\; Q_i\)
Orifice Area formula |
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\( A_0 \;=\; Q \;/\; C_d \; \sqrt{ 2 \; G \; h_c } \) (Orifice Area) \( Q \;=\; A_o \; C_d \; \sqrt{ 2 \; G \; h_c } \) \( C_d \;=\; Q \;/\; A_o \; \sqrt{ 2 \; G \; h_c } \) \( G \;=\; ( Q \;/\; C_d \; A_o )^2 \;/\; 2 \; h_c \) \( h_c \;=\; ( Q \;/\; A_o \; C_d )^2 \;/\; 2 \; G \) |
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| Symbol | English | Metric |
| \( A_o \) = Orifice Area | \( in^2 \) | \( mm^2 \) |
| \( Q \) = Orifice Flow Rate | \(ft^3 \;/\; sec\) | \(m^3 \;/\; s\) |
| \( C_d \) = Orifice Discharge Coefficient | \( dimensionless \) | \( dimensionless \) |
| \( G \) = Orifice Gravitational Constant | \(lbf-ft^2 \;/\; lbm^2\) | \(N - m^2 \;/\; kg^2\) |
| \( h_c \) = Orifice Center of Head | \( in \) | \( mm \) |
