Improved method of index test to determine the turbine efficiency

Abstract

The basic principle of index test is introduced firstly in this paper, then the difficulties to determine the correct flow differential coefficients on site test to measure and evaluate the discharge and efficiency of prototype turbine by the previous research are concluded. An improved method of index test is proposed to evaluate the prototype turbine efficiency with the measured relative efficiency determined by index test result at different net heads. The turbine efficiency is evaluated by the comparison between the measured result and the predicted values as the relative efficiency. Finally, this improved method is applied to a Francis turbine of a large hydropower station in China. Test result show that the relative efficiency of the improved index method is close to the predicted values from the turbine manufacturer and accepted by the all parties of the project. This improved method is an available solution and helpful reference to proceed index test for prototype turbine. However, due to the lack of accurate discharge, this improved method may be applied to evaluate the guaranteed values and penalties in the contract only when an agreement is made by all parties of the project.

Keywords

prototype turbine / turbine efficiency / index test / relative efficiency / weighted efficiency