Energy efficient analysis of bulb turbine in the environment of cavitation with model study in small hydroelectric power plants

摘要

The most important effects of cavitation are major damages to the solid surfaces, vibration, and reduction in turbine efficiency which have been experienced in this study with a model analysis where a bulb turbine model is tested for cavitation phenomena at various guide vane and runner vane openings. Further plant cavitation factor, critical cavitation factor, critical cavitation factor by solving empirical equation and percentage of reduction in turbine efficiency are calculated for the specific speed of the model turbine. The model test report for critical cavitation factor and turbine efficiency are compared to the analytical results and found a reduction of 1 to 1.53 percentage of turbine efficiency during cavitation region operation. The empirical formula derived for the critical cavitation factor is compared to an actual critical cavitation factor and found both are comparatively same. Hence the empirical formula for cavitation is recommended for arriving the critical cavitation factor for a particular operation of the prototype turbines in the power stations without model studies which is an advantage for selecting the safe operation of bulb turbine installed in the most of the hydropower stations.