Cylindrical orifice testing in laminar flow with the orifice diameter ratio β=0.5

The paper presents the results of an experimental study of a cylindrical orifice with the orifice diameter ratio beta = 0.5 and the flow opening length-to-diameter ratio L/d = 1, with hydraulic oil flowing in the DN50 measuring channel. The measurements of the values characterising the oil flow were made in the laminar flow regime, for the Reynolds numbers ranging between Re = 100 to 950. Based on the experimental tests, standard flow characteristics were created for four kinematic viscosity values in the range of 13.4-33.3 cSt, for which the average value of the discharge coefficient C in the tested flow rate range of q(v) < 0.5 dm(3)/s was determined.