Selection of the Diffuser Type and Optimization of the Flow Path Part of a Low Speed Multistage Centrifugal Pump

Abstract

The issue of ensuring high energy efficiency of high-power pumps is relevant, since an in-crease in hydraulic efficiency of such pump flow parts leads to significant savings in the operation costs. Introduction of digital simulation technologies for the viscous fluid flow makes it possible to optimize geometry of the flow path elements at the design stage and predict pump characteristics with sufficient degree of accuracy. The main elements influencing characteristics of the multi-stage pumps flow parts include impellers and taps. Most often, vane and channel diffusers are used as retractors in the multistage pumps. Results of designing and optimizing flow parts of the low speed multistage centrifugal pump with both types of diffusers are presented, as well as predictive characteristics of pumps obtained using the computational fluid dynamics methods. Hydraulic efficiency of a stage with the channel-type guide (optimized version) is by 0.3 % higher than the efficiency of a stage with the vane-type guide. Both optimized flow paths have a non-sinking nature of pressure characteristics in the low flow region. The pump stage with the channel-type guide has a smaller radial overall dimension than the stage with the vane diffuser = 0.88) and higher design manufacturability. It was found that the most preferable option for the feed electric pump stage with the ns = 85 speed factor is the optimized flow path with the channel-type diffuser