Performance Analysis of Micro Francis Turbine Manufactured Locally in Nepal

Abstract

The manufacturing of micro-hydro turbines, especially Cross-Flow, Pelton, Propeller turbine, has been carried for more than 50 years in Nepal. A prominent opportunity in the manufacturing of Francis turbines has been perceived in recent years as the requirements of turbines for future installations falls on the Francis turbine range and are above 60%. However, none of the manufacturers step forward to accept the challenges of manufacturing Francis turbines which may be due to the lack of know-how in design and the manufacturing technology of Francis Turbine as a whole. Nevertheless, many attempts have been put forward with the initiation of the Turbine Testing Laboratory, Kathmandu University, for the development of both the design and manufacturing methodology. In this paper, the performance analysis of two different Francis runners, manufactured using local technology of investment casting and pressing-welding method, was conducted. For making the manufacturing, installation and, operations of the turbine as simple as possible, the trapezoidal spiral casing with fixed guide vanes was implemented. In addition the leading and trailing edge modification had not been carried out so as to observe the efficiency rise after these modifications. A comparison of the efficiency for both the turbines indicates Francis turbines with fairly good efficiencies can be manufactured using locally available tools and technology.