Study on the Cavitation Performances and Unsteady Characteristics of a Centrifugal Fire Pump

Centrifugal fire pumps are critical for firefighting systems but suffer from cavitation and instability under off-design conditions. However, systematic analyses of their flow-rate-dependent dynamics remain limited. This study systematically investigates the hydraulic performance, cavitation characteristics, and dynamic pressure pulsations of a centrifugal fire pump under various flow conditions (۵۰%–۱۵۰% of the design flow rate) through combined numerical simulations and experiments. Steady simulations were conducted using the standard κ-ε turbulence model, while unsteady simulations were performed with a ۲° angular time step to capture the transient interactions between the impeller and the volute as well as the resulting dynamic pressure pulsations. Key results revealed that: At low flow (۶۰% Qd)， Radial force amplitudes increased by ۴۰%, accompanied by ۹.۸۶ Hz low-frequency pulsations attributed to backflow-induced instabilities; At high flow (۱۵۰% Qd), The critical cavitation number σ₃% surged to ۰.۹۶۱, indicating a ۲.۶-fold cavitation risk compared to the design condition (σ₃% = ۰.۳۷۶); The findings provide actionable strategies for optimizing pump design and operational stability in firefighting systems.

Keywords:

Centrifugal fire pump , Hydraulic performance , Cavitation performance , Hydraulic forces , Unsteady characteristics , Pressure pulsation , Numerical simulation