Experimental and Computational Study on the Impact of Aerodynamic Load Distribution on Aerodynamic Performance of Variable-Speed Turbine Blade

Abstract

Abstract Improving the adaptability of variable speed turbine blades to incidence angle by optimizing blade aerodynamic load design is one of the effective technical means to realize the efficient operation of variable-speed turbine blades in a wide range of incidence angle and improve the performance of variable speed turbine. In this paper, cascade experiments and numerical simulation study are carried out under a wide range of incidence angles for three variable-speed turbine blades with different aerodynamic load distributions. The results show that, under the positive incidence angle, the sharp increase of loss mainly occurs in the front part of the suction surface, while the loss increase in other areas is not obvious. Under the negative incidence angle, the sharp increase of loss mainly occurs in the middle and rear parts of the pressure surface. Under the extreme negative incident angle, the increase of loss caused by the middle and rear part of the pressure surface accounted for more than 90% of the total loss increment, while the loss caused by the middle part of the suction surface affecting the flow at the rear of the suction surface accounts for less than 10%. The suitable fore-loaded blades design can greatly broaden the working range at negative incidence angle, while aft-loaded blades can slightly reduce the blade loss at positive incidence angle.