Study on the effects of inducer on the performance and critical point of gas binding of centrifugal pumps

Abstract

In this paper, experimental methods were used to compare the hydraulic performance and anti-gas-binding performance of a centrifugal pump under two conditions: without an inducer (Pump 1) and with an inducer (Pump 2). Meanwhile, CFD numerical simulation was employed to establish three‑dimensional steady‑state models for pure liquid flow and three‑dimensional transient models for gas‑liquid two‑phase flow for both pumps. The influence of the inducer on the performance of the centrifugal pump under pure liquid conditions was analyzed, and the external characteristics and internal flow field evolution of Pump 2 at different gas‑volume fractions were further investigated. The results show that the head and efficiency of the pump decrease significantly with increasing gas‑volume fraction, and the head drops more rapidly under low flow rate conditions. Gas accumulation in the impeller inlet region is the primary cause of gas binding. When the gas volume fraction (GVF) reaches ≥2%, large-scale flow channel blockage begins to occur inside the pump, leading to a sharp drop in flow rate and head. By installing an inducer with a specific geometry at the inlet, the anti-gas-binding capacity can be enhanced, delaying the gas-binding critical point to approximately GVF=4%. However, the addition of the inducer results in a 9.6% reduction in the hydraulic efficiency of the main pump.