基于串联叶片式叶轮的液力透平性能OA

Aiming at the shortcomings of low efficiency,narrow high-efficiency range,and unstable operation when a centrifugal pump is reversed to work as a hydraulic turbine,a centrifugal pump with a specific speed of 69(operated in reverse as a turbine)was taken as the research object.With other impeller parameters kept unchanged,the tandem-blade impeller was designed with the following pa-rameters:a radial segmentation position of 0.8D2,a radial relative length of 30.0 mm,and a circum-ferential relative distance of 5.0 mm,to study the influence of the tandem-blade configuration on the performance of the hydraulic turbine.Hydraulic characteristic tests were conducted on the hydraulic turbine,and the RNG k-ε turbulence model was adopted for numerical simulation of the turbine.The hydraulic characteristics,internal flow field,energy conversion,and pressure pulsation characteristics of the hydraulic turbine with traditional blades and that with tandem-blades were compared and ana-lyzed.The results show that the tandem-blades have a certain impact on the performance of the hydrau-lic turbine.Compared with the original model,the efficiency under the optimal operating condition is increased by 1.37％.The efficiency is improved within the flow range of 0.875QBEP-1.375QBEP of the turbine,and the operating high-efficiency range is widened.Furthermore,the internal pressure distri-bution of the turbine becomes more uniform,the separation flow at the impeller inlet is significantly im-proved,the high turbulent kinetic energy area inside the impeller is notably reduced,the power loss in the impeller decreases,and the main frequency amplitude of pressure pulsation is significantly reduced in both the impeller inlet and outlet regions.