Optimization Design of Low-Shaft-Power Single-Stage Centrifugal Fire Pump Based on Orthogonal Experiment

In firefighting operations, the efficiency of centrifugal fire pumps is crucial for effective fire suppression. Designs aiming for lower shaft power enhance not only the pump’s energy efficiency and reliability but also lead to a reduction in size and weight. This research targets a single-stage centrifugal fire pump with a specific speed of 44.5, employing numerical simulations alongside orthogonal experiments to primarily focus on reducing shaft power. Based on a prototype, an L16(44) orthogonal experiment was conducted on four critical parameters: blade outlet angle, wrap angle, outlet width, and blade count. The study analyzed the impact of these parameters on pump performance, clarifying their influence on the hydraulic performance and proposing an optimal power-efficiency scheme. The optimized design successfully reduced the motor power from 18.5 kW to 15 kW, improved the impeller’s internal flow, minimized flow losses, and effectively managed the hump phenomenon. Operating at 1.5 Qn, the optimized pump’s power decreased by 2.67 kW, meeting head requirements while boosting efficiency, reducing resonance frequency, and lowering the pressure amplitude at the tongue. The optimized pump’s blade frequency distribution was more regular than the original, with the first-order mode’s average deformation decreasing from 3.6 mm to 3.3 mm, and average entropy production at rated flow dropping from 424.118 [W·m−3·K−1] to 384.957 [W·m−3·K−1]. These outcomes offer theoretical insights and practical guidance for designing low-shaft-power single-stage centrifugal fire pumps, significantly impacting energy efficiency and operational costs.