Metrological Comparison of Metering Characteristics of Differential Pressure Meters

摘要

It is often difficult to realize calibrated accuracy of a flow metering system over measurement range when it is installed under hostile and perturbed flow conditions. Though widespread studies are reported in literature on individual characteristics of meters, comparative evaluation of the performance of these devices under real life installation situations is relatively inadequate. Present study compares classical venturi, cone, standard orifice and new slotted orifice and four hole orifice meters. Experiments are carried out to investigate the effects of single elbow, double elbow in and out of plane, reducer, and expander on the response characteristics of these devices. Discharge coefficients and pressure loss characteristics are analyzed and compared. Pressure and velocity variations created by the flow element restrictions with adjacent meter tubing are also analyzed with computational fluid dynamic simulations. Minimum upstream straight pipe lengths to suppress the effects for each of these tested flow meters are proposed.