Abstract: As the core equipment in high-head hydropower harvesting, the impulse turbine has the advantages of higher operating head and wider high-efficiency range compared with reaction turbines. However, features of flow fields within a Pelton turbine are open, unsteady and multi-phase. Complex flow characteristics affected by multiple flow transitions and component-matching of the Pelton turbine may exert influence on its performance and utilizing efficiency of high-head hydropower. Recent advances in impulse turbine technologies have been accelerated by the rapid development of visual test technology, computational fluid dynamics (CFD), finite element method (FEM), and artificial intelligence optimization design algorithm. The technology of impulse turbines developed late but rapid in China, summarizing by three stages from scratch, independent design to optimization, and breakthrough progresses have been accomplished especially in the past 20 years. Based on a comprehensive synthesis of researches from both national and international impulse turbines researching field, this paper focuses on the main progresses of impulse turbine technology in the past 20 years, and reviews the recent advances in the research of internal flow characteristics, sediment abrasion, failure analysis, and optimization design theories. Several issues with performance analysis and optimization design are discussed, and the development trend of impulse turbine technology is summarized and prospected.

Key words: impulse turbine, internal flow, sediment abrasion, failure analysis, optimization design, bucket