Orifice contraction coefficient for inviscid incompressible flow
Abstract
The theory for steady flow of an incompressible fluid through an orifice has been semiempirically established for only certain flow conditions. In this paper, the development of a more rigorous theory for the prediction of the orifice flow contraction effect is presented. This theory is based on the conservation of momentum and mass principles applied to global control volumes for continuum flow. The control volumes are chosen to have a particular geometric construction which is based on certain characteristics of the NavierStokes equations for incompressible and, in the limit, inviscid flow. The treatment is restricted to steady incompressible, single phase, single component, inviscid Newtonian flow, but the principles that are developed hold for more general conditions. The resultant equations predict the orifice contraction coefficient as a function of the upstream geometry ratio for both axisymmetric and twodimensional flow fields. The predicted contraction coefficient values agree with experimental orifice discharge coefficient data without the need for empirical adjustment.
 Publication:

ASME Journal of Fluids Engineering
 Pub Date:
 March 1985
 Bibcode:
 1985ATJFE.107...36G
 Keywords:

 Flow Coefficients;
 Flow Geometry;
 Flow Theory;
 Incompressible Flow;
 Inviscid Flow;
 Orifice Flow;
 Axisymmetric Flow;
 Contraction;
 Discharge Coefficient;
 High Reynolds Number;
 NavierStokes Equation;
 Two Dimensional Flow;
 Upstream;
 Wall Pressure;
 Fluid Mechanics and Heat Transfer