Numerical and Experimental investigation performance of industrial orifice flowmeter in a power plant

One of the most common  of measuring  mass fluid flow rate through the  pipes are  orifice flowmeter. Orifice flowmeters work based on the fluid pressure difference before and after of the orifice which could be measured acual mass flow rate. The orifice pressure drop and the discharge coefficient are related on geometrical shape of orifice, the ratio of orifice diameter  to the pipe diameter and  Reynolds number of fluid flow. In this study, the performance and accuracy of an orifice flow meter for measuring the mass flow rate of cooling water in a sample thermal power plant  is examined. In order to determine the water pressure drop on both sides of the discharge orifice, the orifice flowmeter with connections taken into account and fluid flow inside it is simulated. Due to the turbulent flow of water, the standard k-e turbulence model is used. The performance orifice curve has been obtained numerically and it compares with the actual performance curve orifice obtained from experimental data. This comparision shows a good match. Also the orifice discharge coefficient obtained by numerical and experimental methods and compared with values given by valid standards that indicates good agreement. The numerical analysis has determined that maximum flow velocity  occurs about one orifice diameter downstream of the orifice location and in this point, velocity of  flow is more than four times the average velocity of flow in the pipe entrance.