Design technique to improve the energy efficiency of a counter-rotating type pump-turbine

摘要

The counter-rotating type pump-turbine is an advanced concept unit optimized for the renewable energy fields such as small hydraulic power for energy generation and power stabilization systems for energy storage purposes. Given the unique operational mechanism of the counter-rotating type pump-turbine, it has extremely complex internal flow patterns. More methodical and rational design techniques are therefore required to ensure the improved energy efficiency of this unit. In this study, the existing design was adapted to improve the system efficiency of the counter-rotating type pump-turbine by applying a design method, combining design of experiment (DOE) with numerical analysis. The design variables and the test sets were selected to perform the DOE design using a 2(k) factorial design. The influence of each design variable on the system performance was analysed based on the results of the performance evaluation on the test sets, as the regression analysis for the 2(k) factorial design was performed. Furthermore, the respective model, whose efficiency was improved according to the operating mode, was produced. Finally, the performance of each generated model was evaluated using numerical analysis, and it was confirmed that its system efficiency has indeed improved. (C) 2016 Elsevier Ltd. All rights reserved.