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This study simulates the flow through a small-scale open cross-flow hydraulic turbine and analyzes the turbine’s performance. The simulation employs a two-dimensional particle method that was used for the simulation of a small-scale impulse-type hydraulic turbine in a prior study. Flow in the turbine is successfully simulated, with the simulated turbine performance showing good agreement with experimental measurements. The simulations also clarify that the deterioration in performance with increasing water flow rate is caused by the degeneration of the radially outward flow between the rotor blades.

To investigate flow patterns on the bucket of Pelton turbine runners is one of the important issues to improve the turbine performance. By studying the mechanism of loss generation on the flow around the bucket, it becomes possible to optimize the design of inner and outer bucket shape. For making it into study, computational fluid dynamics (CFD) is quite an effective method. It is normally used to simulate the flow in turbines and to expect the turbine performances in the development for many kind of water turbine including Pelton type. Especially in the bucket development, the numerical investigations are more useful than observations and measurements obtained in the model test to understand the transient flow patterns. In this paper, a numerical study on two different design buckets is introduced. The simplified analysis domain with consideration for reduction of computational load is also introduced. Furthermore the model tests of two buckets are also performed by using the same test equipment. As the results of the model test, a difference of turbine efficiency is clearly confirmed. The trend of calculated efficiencies on both buckets agrees with the experiment. To investigate the causes of that, the difference of unsteady flow patterns between two buckets is discussed based on the results of numerical analysis.