EFFECTS OF CAVITATION AND PLATE THICKNESS ON SMALL-DIAMETER RATIO ORIFICE METERS

High differential pressure drop is frequently required in the process line of electric power plants. However, cavitation produced by a high pressure drop could damage the pipe and pump blades. In these experime nts, the effects of cavitation and plate thickness for small-bore diam eter (d) to pipe diameter (D) ratio (beta = d/D) orifice plates were e valuated in a 100 mm diameter test section of a water flow calibration facility. Three size orifice meters were tested with beta = 0.10, 0.1 5, and 0.33 and no bevel on the throat. The cavitation number at incep tion was measured to be 1.0 to 1.2 for all experiments. Although cavit ation occurred in all experiments, the discharge coefficient was affec ted by cavitation only for the smallest bore (beta = 0.10) and thickes t plate tested, 7.0 mm or t/d = 0.70 where t is the plate thickness. T hickness seemed to influence the discharge coefficient only for the be ta = 0.10 plate. But the trends in the results for thickness were not conclusive and could be attributed to edge sharpness. (C) 1998. Publis hed by Elsevier Science Ltd.