A NUMERICAL STUDY OF TURBULENT-FLOW THROUGH A VARIABLE AREA ORIFICE METER

The paper describes a numerical study of turbulent flow through an ori fice plate restricted by an obstruction of conical shape at its centre . Such a situation occurs in flow metering devices which work an the p rinciple of variable flow area rather than fixed area, as in simple or ifice plate meters. The governing differential equations, of continuit y and momentum and the equations for the k-epsilon model of turbulence are solved using a finite element method. The velocity and pressure f ields and the variation of pressure along the pipe wall are presented. The results show a significant rise in the irrecoverable pressure los s which may reduce the advantage of the meter over simple orifice mete rs in practice. For comparison, the how field for a simple orifice pla te of the same overall geometry has also been presented. The discharge coefficient for this latter case has been predicted with an error of about 1%, compared with published empirical data.