Numerical Study on the Flow Characteristics of Low Head Small Hydraulic Turbine

A small hydraulic turbine more still remains to improve the mechanical performance because it does not come fully similarity as compared with the large-scale hydraulic turbine. Many studies on the small hydraulic turbine focused on the increase of performance. In this study, the characteristics of axial propeller turbine which is appropriate equipment for low head conditions and high flow rates were numerically investigated using the commercial code, ANSYS CFX. A parametric study was carried out with two different geometrical parameters, such as blade number and tip clearance between casing and blade. Results showed that the hydraulic loss was increased and the efficiency of small hydraulic turbine was decreased because of increasing tip clearances, which lead to the increase of absolute velocity at the exit of the runner blade.