The impact of hub ratio on the performance of helico-axial gas–liquid multiphase pumps

The Helico-Axial Gas–Liquid Multiphase Pump is one of the core devices in subsea oil extraction. The gas-liquid separation within the pump exacerbates hydraulic losses, significantly limiting its performance and application. Reducing gas-liquid separation to enhance the pump's boosting capacity has become a key focus of current research. This study optimizes the multiphase pump by altering the hub ratio and using the grey relational analysis method, thereby determining the optimal hub ratio within a specific range. The results indicate that the primary pressurization occurs in the front half of the impeller in the gas-liquid multiphase pump. A reasonable hub ratio promotes the re-mixing of the gas and liquid phases in the latter half, reducing hydraulic losses caused by gas phase aggregation. Within the specific range of specific speeds (150 to 250), the optimal hub ratio exhibits a linear and monotonically decreasing relationship with specific speed. Additionally, the hub ratio has a greater influence on the external characteristics of the pump.