Flowrate Measurement of Gas–Liquid Two-Phase Flow Using a Throat-Extended Venturi Tube and a Microwave Resonant Cavity

This article presents a novel method for flowrate measurement of gas–liquid two-phase flow using a throat-extended Venturi tube (TEVT) combined with a microwave resonant cavity (MRC). First, a total flowrate model is developed from differential pressure (DP) equations across the convergent and straight sections of the TEVT. Subsequently, a gas–liquid flowrate ratio model is established using microwave resonant frequency and multiple DP fluctuations, fit via support vector machine (SVM). The particle swarm optimization (PSO) algorithm then solves the coupled equations for gas and liquid flowrates. The proposed method integrates two sensing modalities and leverages static and dynamic features of raw measurement data to achieve simultaneous gas–liquid flowrate prediction. Experiments were conducted on a gas–liquid two-phase flow test facility using the TEVT and MRC. Within gas flowrate of 0.07–8.09 m³/h and liquid flowrate of 1.12–13.64 m³/h, the relative errors of the predicted liquid and gas flowrates are within ±5% and ±9.5%, respectively. The results demonstrate that the proposed method performs well in predicting gas–liquid two-phase flowrate, offering potential for extension to broader range of flow conditions.