Knowledge discovery of injector geometry effects on Pelton turbine erosion: Approaches for efficient high-head water utilization

The Pelton turbine is an effective method to utilize high-head water resources. However, high-speed, sand-laden water impacts the injector and bucket in the Pelton turbine, eroding structural surfaces and compromising operational safety. This study systematically investigates the interactions among key structural design variables and develops a knowledge discovery framework aimed at enhancing the erosion resistance of Pelton turbine injectors. Primarily, the Oka model is applied to quantitatively evaluate the impact of varying particle sizes on injector erosion. Subsequently, the injector is optimized using Multi-Point Search-based Efficient Global Optimization (MSEGO), where key design variables include needle angle, nozzle angle, needle diameter, and needle transition diameter. As a result of the optimization process, the average erosion rates at the nozzle throat and needle transition are reduced by 93.90 % and 93.67 %, respectively, indicating a significant enhancement in erosion resistance. To further refine the understanding of erosion mechanisms, the synergistic effects of design variables on erosion performance are comprehensively analyzed through advanced data mining techniques, incorporating parallel coordinate system visualization and Analysis of Variance (ANOVA). Therefore, this study not only presents a systematic design optimization strategy but also offers a robust, data-driven framework for enhancing the durability and operational efficiency of injectors.