Influence of the Gas Model on the Performance and Flow Field Prediction of a Gas–Liquid Two-Phase Hydraulic Turbine

A two-phase hydraulic turbine’s performance and flow field were predicted under different Inlet Gas Volume Fractions (IGVF) with incompressible compressible models, respectively. The calculation equation of equivalent head, efficiency, loss considering the expanding work gas deduced based on energy conservation equations. Then, results, including output power fields, are compared analyzed. model’s power, higher than model, but efficiency is lower. As IGVF increases, gradually diffuses from blade’s working surface to its suction surface. gas–liquid separation happens at runner outlet in results due expansion. area low-pressure zone increases IGVF. However, it decreases results. expands blade passage, takes up more area, causing high liquid velocity same passage. runner’s inlet distribution affects angle, shock TKE areas, especially passage near volute tongue. larger because impact higher. This paper provides a reference for selecting models numerical simulation turbines.