Soft measurement model for wet gas flow rate based on ultrasonic and differential pressure sensing

Abstract

Non-separation measurement of gas-liquid two-phase flow is of great significance to industrial production and theoretical research on two-phase flow. In this paper, a soft measurement method of wet gas flow rate based on ultrasonic and differential pressure sensors is proposed. A total of 129 sets of experimental data are obtained in DN50 horizontal pipe, the superficial velocity of gas and liquid ranging from 5m/s to 33m/s and 0.015m/s to 0.6m/s, respectively. Ten feature parameters of ultrasonic signals such as the time difference between two echoes and kurtosis factor are proposed from time and frequency domain. As well as the power spectral density, mean value and standard deviation value are analyzed based on differential pressure signals. Furthermore, the Spearman correlation coefficient is introduced to evaluate these feature parameters quantitatively. And nine parameters which are highly correlated to gas-liquid flow rate are selected as the inputs of the soft measurement model. Finally, Decision Tree, LS-SVM and ANN models are established through training with the experimental data. Comparison results show that ANN has the lowest prediction errors on the test set, with the mean absolute percentage errors(MAPE) of 1.49% and 3.2% for gas and liquid, respectively.