PERFORMANCE EVALUATION OF AXIAL FLOW PUMP AS TURBINE

Abstract

Energy is the basic requirement for economic development. Every sector of a country's economy needs input of energy. As the nonrenewable fossil energy sources continues to deplete and realizing the summits -held at . Brazil , Kyoto, Copenhagen to reduce the greenhouse gas emissions, hydropower has moved towards the top power development option to meet the increasing energy demand. Pump as Turbine has been effectively used in micro hydro power sector for a quite a long time. The use of Pump as Turbine in lieu of conventional custom made turbine has brought down the electro mechanical cost, which contributes a major share in the installation cost of micro hydro power plants and thereby making micro hydro power plants more economically feasible. A lot of work has been carried out in the area of Pump as Turbine especially in analyzing the performance of pumps in turbine mode. A few works has been directed towards suggesting methods to improve the efficiency of pump in the turbine mode of operation. It was however found out that very little work is available in the literature on the use of axial flow pump in turbine mode. These pumps are used for low head and high discharge. In the Himalayan. region a number of water mill sites exist where the head range is of the order of 3-5 m with a capacity of up to 5 kW. The potential of these sites can be harnessed effectively by the use of efficient equipment. Use of axial pumps as turbines can be a good option for such sites. Keeping this in view the present study has been carried out. Under the present investigation an axial flow pump which can be used in the micro hydro range is dimensioned and fabricated .Computational Fluid Dynamic analysis using the commercially available FLUENT package was carried out to simulate the flow in the turbine mode operation of the pump. The pump was tested in the turbine mode to determine its operating characteristics and the results obtained from the experimentation was compared with simulation results which are found to be in good agreement.