Orifice Plate

When a fluid passes through the orifice plate, its pressure builds up slightly upstream of the orifice. But as the fluid is forced to converge to pass through the hole with diameter do, the velocity increases and the fluid pressure decreases. The difference in pressure is the pressure drop Δp. The following calculation is only a rough approximation.

dp Diameter pipe mm
do Diameter orifice plate mm
Q Flow rate m3/h
η Dynamic viscosity mPa·s
ρ Fluid density kg/m3
v Velocity in pipe 1.5 m/s
Re Reynolds number 73535 [/]
β Diameter ratio (diameter orifice / diameter pipe) 0.48 [/]
C Friction coefficient 0.621 [/]
Δp Pressure drop 0.55 bar

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