THE PERFORMANCE OF A MULTPATH, 8-INCH ULTRASONIC METER IN PULSATING FLOW

摘要

The performance of a 200 mm (8-inch) FMC EnergySystems (also referred to as Kongsberg) multipath ultrasonic flow meter in high pressure pulsating natural gas flows was evaluated and is discussed in this paper. The tested meter performed within +-0.5percent of reference flow so long as the root-mean-square (RMS) value of the pulsating velocity component (V_(RMS)) at the meter location did not exceed 0.7 m/sec. This statement also appears to be true for V_(RMS) values that are less than 10percent of the mean flow velocity at the meter location. The flow rate measurement errors exceeded +-1percent at V_(RMS) > 1 m/sec. Performance of the meter depends on the level of V_(RMS) at the meter location and not the RMS of the pulsating pressure component (P_(RMS)). Unexpectedly, disabling four out of six operating paths generally improved flow meter performance under pulsating flow conditions. Additional information to definitively explain this result is needed although speculative comment is provided about the possible cause. The evaluated multi-path ultrasonic flow meter performed well under pulsating flow conditions up to a certain pulsation threshold. Meter error as a function of pulsation frequency and pressure/velocity amplitude is presented and discussed.