Effect Of Flow Discharge And Shaft Slope Of Archimides (Screw) Turbin On The Micro-Hydro Power Plant

Abstract

A renewable energy source for mini / micro hydro usually exploits the potential energy of water flow that have certain head and the specific discharge which is converted into electrical energy through a turbine and generator. However, in many rivers, the average of water resource potential has a large discharge and low head. Thus, the development of a low head turbine or a very low head is very suitable to be developed in Indonesia. Screw turbine uses low head and high flow rate of water to generate torque and rotation as mechanic energy. Screw turbine has many advantages such as simple in construction and installation, low cost in operating and maintenance, and fish-friendly. The influencing parameters to mechanics performance of screw turbine are pitch distance, water discharge and the shaft slope. The objective of this research is to investigate the effect of shaft slope angle and discharge variations to mechanics performance of a 2-blades screw turbine in laboratory scale. A model used in the research was a 2-blades screw turbine, pitch (distance of a screw wave) is 1.6 Ro, external radius (Ro) is 0.1419 m, and internal radius (Ri) is 0.0762 m. The screw turbine was tested in Hydraulic Laboratory of the Vocational School of Civil Engineering, Gadjah Mada University, with various average discharges of water was about 0.00364 m3/s to 0.00684 m3/s, and the angle of turbine shaft slope was from 25°to50°. The result of the testing showed that the discharge and turbine shaft slope affected the turbine power and efficiency. The highest turbine power and efficiency were produced at average discharge was 0.00684 m3/s. The optimum screw turbine shaft slope was 35o, indicated by the output power of screw turbine of 16.231 watt and the efficiency of 61.61%.