Interfacial wave parameters measurement based on flow noise decoupling in horizontal annular flow

Annular flow is a typical gas–liquid two-phase flow pattern, where interface behavior characteristics significantly affect the stable operation of devices. Interfacial wave parameters reflect the spatial behavior of interfacial wave fluctuations, making them essential for studying annular flow mechanisms. This study designs the measurement method for interfacial wave parameters depending on acoustic emission technique. The interfacial wave parameters of a horizontal pipe’s annular flow are measured experimentally under various flow conditions. The noise signals of annular flow with various flow conditions are measured, and the Whale Optimization Algorithm for Variational Mode Decomposition is used to evaluate the acoustic emission signals. By analyzing the initial signals’ energy and entropy, the decoupling of annular flow noise is achieved. The disturbance wave frequency and disturbance wave velocity are determined by analyzing the flow noise signals in the time domain. Reynolds number and intrinsic mode component energy are extracted, then the CatBoost algorithm is used to create a prediction model for the frequency and velocity of disturbance waves in annular flow. The results show that the MAPE of the disturbance wave frequency prediction model is 9.84 %, with 85.00 % of the experimental points having a relative error within ± 15 % band. The MAPE of the disturbance wave velocity prediction model is 4.31 %, with 95.00 % of the experimental points having a relative error within ± 15 % band.