Dr.-Ing. Zh. Zhang graduated from the School of Energy & Power Engineering of Xi’an Jiaotong University (PR China) in 1981. He received his PhD at the Institute of Thermo and Fluid Dynamics of Ruhr-University Bochum (Germany). Afterwards he joined Sulzer Markets & Technology Ltd in Winterthur, Switzerland, for experimental research of engineering flows. During this time he was awarded the company innovation prize. He changed later to the Oberhasli Hydroelectric Power Company (KWO) and later to Rütschi Fluids AG. Currently he is a visit engineer for supporting the research projects at the Laboratory of Hydraulics, Hydrology and Glaciology (VAW) of the Swiss Federal Institute of Technology in Zurich (ETHZ). He is the author of the monographs «Freistrahlturbinen» 2008 and «LDA Application Methods» 2010. In 2014, he was elected to ASME Fellow.

• Introduction.- Working principle of Pelton turbines.- Injector characteristics.- Jet characteristics and measurements.- Interaction between the jet and Pelton wheel.- Fluid mechanics in the rotating bucket.- Water spreading in the rotating bucket.- Exit flow conditions.- Exit flows and hydraulic losses.- Fricton effects and flow friction theorem.- Viscous cross-flow through the bucket.- Viscous longitudinal flow through the bucket.- Friction and windage losses in Pelton wheels.- Power loss due to bearing frictions.- Hydraulic and mechanical efficiency.- Real hydraulic efficiency characteristics.- Runaway speed and acceleration profile.- Hydraulic design of Pelton turbines.- Multi-jet Pelton turbines.- Geometric and hydraulic similarities.- Model turbine tests and efficiency scale-up.- Sand abrasion and particle motion in the bucket flow.- Bucket mechanical strength and similarity laws.- Appendices: Nomenclature.- Definition of derived parameters.- Specific speed and application in Pelton turbines.- Specification of the jet piece for a bucket.- Specification of the bucket positions.- Particle motion along the streamlines in the Pelton Bucket.