Influence of differential pressure fluctuation on flow measurement of gas-liquid two-phase flow in orifice plate

Differential pressure fluctuation is an inherent physical phenomenon in gas-liquid two-phase flow, which can be used to measure the quality and the whole flowrate. In order to study the influence of differential pressure fluctuation on gas-liquid two-phase flow metering for orifice plate, the differential pressure fluctuating processes under different flow conditions were measured, with the pressure ranging from 0.7 MPa to 1.0 MPa, the gas mass flow rate ranging from 200 kg/h to 400 kg/h, and the quality ranging from 0.4 to 1.0, respectively. The experimental results show that the mean value of the differential pressure and the standard deviation of the differential pressure could reflect changes of the flow parameters of the two-phase flow, whereas the standard deviation of the differential pressure is with poor repeatability. In the experiments, the repeatability of the standard deviation varied in the range of ±0.3%~±18.5%. For the two phase flow with low liquid content (LVF<0.3%), changes of differential pressure caused by the liquid phase could be 'masked' by the fluctuation of the differential pressure. Due to error propagation, the prediction error of the whole flowrate is larger than that of the quality. For two-phase flow with quality higher than 0.5, error propagation could enlarge the prediction error ofthe liquid phase.