Pressure losses across orifice plates, perforated plates and thick orifice plates in ducts

This Data Item is available as part of the ESDU Sub-series on Fluid Mechanics Internal Flow. Basic pressure loss coefficient data for use in the calculation of pressure losses for incompressible flow in ducts containing orifice plates, perforated plates and thick orifice plates or in the determination of a suitable geometry for a pressure reducing orifice in a duct are presented. Data are given for porosities in the range 0.001 to 1.00. Although the data were derived basically for symmetrical arrangements of circular holes in circular plates it was found that they apply reasonably well for square ducts, square holes and small departures from symmetry. General features of flow through orifices are discussed. A flow chart calculation procedure is included. Compressible flow is dealt with in ESDU 82009.