Disturbance wave height prediction model based on Kelvin-Helmholtz instability and interfacial shear
Annular mist flow widely exists in natural gas and other industrial environments,in-depth exploration of the characteristics of disturbance waves is of significant importance for understanding the evolutionary patterns of annular mist flow.Experiments on gas-liquid two-phase flows were conducted in a vertical pipeline with an inner diameter of 15mm at different operating conditions.The liquid film thickness and droplet entrainment ratio were measured using a conductive ring sensor and a liquid film collection system respectively.The disturbance wave height data were extracted from the temporal signals of conductive ring sensor by using a dual-threshold method.The disturbance wave height and entrainment ratio with changes in gas-liquid flow rates and working pressure were investigated.It was found that both of them increased with increasing liquid flow rate,while they decreased with increasing gas phase flow rate and working pressure,indicating a close correlation between them.Then the scale parameters affecting the disturbance wave height were analyzed,and a disturbance wave height prediction model based on Kelvin-Helmholtz instability and interfacial shear was established.The model exhibited a relative root mean square error(rRMSE)of 4.05%,with 98.7%of data points falling within a±10%error range,demonstrating good fitting performance.Finally,a comparison was made between the proposed model and existing disturbance wave height correlations,both prediction accuracy and scalability have been greatly improved.