2020/4/15 Discharge Coefficient Discharge Coefficient Convert discharge coefficient to minor loss coefficient To: LMNO www.LMNOeng.com Click to Calculate Engineering Discharge Coefficient, C: 0.6 home page Diameter Ratio, d/D: 0.5 (full list of Minor Loss Coefficient, K: Will be computed calculators Discharge Coefficient Diagram and Conceptual Flow Lines for an Orifice in a Pipe including more advanced orifice, nozzle, venturi) Discharge Coefficient Equation Valid for 0.4 ≤ C ≤ 0.8 and 0.2 ≤ β ≤ 0.7 Derivation of Discharge Coefficient Equation Steady flow of an incompressible fluid through an orifice based on a discharge coefficient: Pressure loss from location 1 to 3 in the pipe written in terms of discharge coefficient: Pressure loss from 1 to 3 in the pipe due to the orifice written in terms of minor loss coefficient: Also: https://www.lmnoeng.com/Pressure/DischargeCoefficient.php 1/2 2020/4/15 Discharge Coefficient The goal is to solve the above equations for K. Begin by equating discharge coefficient equation (2) to (3): Solve for K in terms of discharge coefficient: Many pipe flow analysis programs do not readily implement orifice discharge coefficients because they use K's instead. Hence, having a value for K based on the orifice discharge coefficient is useful for flow calculators. Symbols and units for discharge coefficient equations: Ao=orifice area (m2), Ap=pipe area (m2), d=orifice diameter (m), D=pipe inside diameter (m), P1-P2=differential pressure (N/m2), P1P3=non-recoverable pressure difference (N/m2), Q=flow rate (m3/s), Vo=velocity through orifice (m/s), Vp=velocity in pipe (m/s), ρ=fluid mass density (kg/m3). Reference for discharge coefficient: LMNO Engineering - Large diameter orifice flow meter calculation for liquids © 2017 LMNO Engineering, Research, and Software, Ltd. All rights reserved. Please contact us for consulting or questions about discharge coefficient. LMNO Engineering, Research, and Software, Ltd. 7860 Angel Ridge Rd. Athens, Ohio 45701 USA Phone: (740) 707-2614 LMNO@LMNOeng.com https://www.LMNOeng.com https://www.lmnoeng.com/Pressure/DischargeCoefficient.php 2/2
