Simulation Research on Liquid Film Thickness of Horizontal Gas-liquid Two-phase Flow Based on Ultrasonic Method

As one of the important characteristic parameters of gas-liquid two-phase flow, liquid film thickness is closely related to pressure drop, void fraction and velocity. Due to the advantages of strong penetrability and little impact on the detection environment, ultrasonic technology is favored by researchers in the measurement of liquid film thickness. However, it has some limitations for thinner liquid film thickness. Therefore, a multiphysics coupling simulation method based on COMSOL is proposed to simulate the direct and inverse piezoelectric process of ultrasonic transducer, and explore the applicability of ultrasonic echo reference signal elimination (UERE) method for measuring the liquid film thickness of gas-liquid two-phase. Under the working conditions of stratified flow and annular flow, the echo signal after the transmitting signal of the ultrasonic transducer passing through the pipe wall-water-air interface is obtained. Combined with the UERE method, the simulation results of liquid film thickness are calculated. And compared with the theoretical value, the relative error is within ±2%. It verifies the correctness of simulation method and the applicability of UERE method in the measurement of liquid film thickness of gas-liquid two-phase flow.