EROSION ANALYSIS OF HYDRO TURBINE MATERIALS

Abstract

In the Himalayan region main and suitable source of energy is hydro power potential of the resion . Many hydro plants have been in operation over last 50 years utilizing the hydro potential for electricity generation. Rain and snow fed rivers originating from Himalayas carries heavy amount of silt content almost 12000ppm which causes heavy erosion of turbine runner and other water part causing degradation of turbine efficiency over a period of time. Such erosive wear of hydro turbine runners is affected by silt size, hardness and concentration, velocity of flow in the turbine, angle of impact and base material properties. In the present study computational methodology has been used using commercial Finite Element Method (FEM) to calculate the erosive wear of different hydro turbines runner materials that may help to evaluate the performance of different materials for a particular type of silt contents. Different plots have been prepared showing erosion rate versus (velocity of water, angle of impact) that will help to choose the best turbine runner material according to site condition. High silt contents in river water has drastically reduced the power generating capacities of several power plants . The runner blade thickness can be reduced from 12-14 to 1-2 mm in a period of 6 months; The rebuilding of runners requires dismantling, transportation and recomissoing that required around 100 days of downtime for each generating unit . The loss of power generation capacity of up to 45% can be due to high silt wear of turbine runners. In silt water quartz content may be over 50%. Under the present Finite Element Method(FEM) approach has been considered. FEM tool is efficient and provides more relevant information about erosion. In the present study a) for analysis the erosion rate of turbine material 13Cr-4Ni ABAQUAS/EXPLICT software has been used. b) An experimental study has been carried out for validation of the analyzed result on the slurry pot machine to perform the experiment the specimen of 13Cr-4Ni is taken. c) By comprising the result of experimental study with FEM results it has been found that both result are comparable.