Generation mechanism and control method of countertorque in the bucket of a Pelton turbine

Abstract

The energy performance and efficiency of Pelton turbine units is the focus of attention in engineering. The countertorque of the bucket during the operation of the Pelton turbine will affect the above indicators of the unit. However, there is still a lack of systematic research on the generation mechanism of countertorque and control strategies. Numerical simulation and experimental research were conducted on a Pelton turbine. It was found that the countertorque of the bucket is generated during the initial contact stage between the jet and the suction surface of the bucket. At this time, the jet acts on the tip of the suction surface of the bucket, generating a force in the opposite direction of the bucket's rotation, resulting in the generation of countertorque. A geometric optimization method is proposed, which suppresses the countertorque by controlling the inclination angle of the bucket. As the inclination angle decreases, the countertorque, pressure, circumferential force, and entropy production rate of the bucket are effectively controlled. Compared to the original scheme, the optimal scheme reduces the maximum countertorque by 49.33% and improves the unit efficiency by 0.57%.