小型円環翼列風洞による超高負荷軸流タービンの空力性能評価

（翼端間隙高さの影響）

抄録

Many studies have been performed to improve the performance of a gas turbine used as power generators and aero-engines. An increase of the turbine blade loading by the increase of blade turning angle is one of the effective methods to improve the aerodynamic performance of axial turbine which is the major component of gas turbine. This method makes it possible to reduce the turbine diameter and the numbers of the blade and the stages by the increase of the blade loading per single turbine blade. As a result, the reductions of the size and the weight of a turbine can be achieved. However, the increase of the turning angle intensifies the passage vortex due to the increase of the pressure gradient across the blade-to-blade passage, and consequently decreases the aerodynamic performance of the turbine cascade. In this study, the effects of the tip clearance size on aerodynamic performance of an ultra-highly loaded turbine cascade（UHLTC）with the turning angle of 160 degree were investigated by using the small sized wind tunnel for an annular turbine cascade．The turbine torque，the total temperature，the total pressure and the casing wall static pressure were measured in order to estimate the stage loading，the aerodynamic loss and the efficiency of UHLTC． The experimental results showed that the decrease of the size of tip clearance enhanced the torque performance and the turbine efficiency because of the reduction of aerodynamic loss.