Flow characteristics of segmental orifice plates

The results of an experimental investigation concerning the characteristics of flow through segmental orifice plates in a circular pipe have been reported. Experiments were conducted in a recirculatory flow system having a pipe of 105 mm diameter and using segmental orifice plates with ratios of orifice area to pipe area a/A=0.20, 0.30, 0.49, 0.66 and 0.84. The data were collected onl for clear water flows. The analysis of data collected in the present study and of those collected by other investigators indicates that for clear water flow through segmented orifice plates, the location of vena contracta and the value of discharge coefficient Cd depend on a/A and the orifice Reynolds number Re=U√a/ν. For Re greater than 1.50×105, the value of Cd depends only on a/A and is given by Cd=0.63+0.55 (a/A)3.40.