Gas Orifice Meter Discharge Coefficients as Determined by Mass Flow Measurements

摘要

Performance data of gas orifice meter runs and plates have been generated under a U.S. gas industry supported program. The data have been developed using nitrogen gas and a unique NBS gas flow measurement facility capable of directly measuring the mass of gas metered by the orifice device. Direct comparison of predictions from empirical equations can now be made at orifice bore Reynolds Numbers near four million. Two meter runs for each of four nominal line sizes and two sets of orifice plates with up to six beta ratios per set were interchanged in order to develop full meter performance characteristics. Orifice meter and flow reference system data are used to calculate discharge and expansion coefficients which in turn are compared to those derived from existing equations. Orifice meter performance data and system descriptions are provided.