Hydraulic Optimization and Experimental Measurement of Low Specific Speed Centrifugal Fire Pump

As one of the core components of the fire-fighting water-supply system, the performance of a fire pump directly determines the extent of damage caused by the fire. Compared with conventional pumps, the design requirements of fire pumps not only need to ensure that the head of the pump is at ۰Qd, ۱.۰Qd, and ۱.۵Qd and its efficiency is at ۱.۰Qd but also consider the cavitation performance at each flow rate, which presents a greater challenge for the design of high-performance fire pumps. By optimizing the design of a centrifugal fire pump with a specific speed of ۲۴.۷, numerical calculations were performed to obtain the best optimized scheme Y۴. The results show that at the design flow rate the best optimized scheme improves the efficiency by ۹.۱۷% compared with the original scheme, and the head meets the design requirements of the fire pump while avoiding the hump phenomenon. Through a comparative analysis, it was found that the optimized scheme Y۴ can reduce the pressure pulsations at the outlet of the pump and improve the cavitation performance at each flow rate. The experiment verifies that the head of the best optimized scheme at the design flow rate is ۷۴.۴۳m, the pump efficiency is ۴۰.۲۲%, and there is no hump in the head curve, which can meet the design and use requirements of the fire pump. The maximum reduction in the outlet pressure pulsations coefficient in the best optimized scheme was ۴۷.۱۲% on average. Compared with the original scheme, the critical net positive suction head (NPSHr) of the best optimized scheme was reduced by ۲۱.۵%, ۱۷.۶%, ۱۵.۷%, and ۱۶.۸%, respectively.

Keywords:

Low specific speed centrifugal pump , Efficiency , Hump , Pressure pulsations , NPSH