An increase of turbine blade loading by the increase of blade turning angle enables to reduce a gas turbinein size and weight by decreasing the number of turbine blades and stages. However, the increase of turbineblade loading would result in the intensification of the secondary flow related to the passage vortex andthe tip leakage vortex, which are caused by the pitchwise pressure gradient on the endwall and thepressure difference between the pressure and the suction surfaces at the blade tip, respectively. In thisstudy, the oil-flow visualization and the detailed internal flow measurements by using the 5-hole Pitot tubewere carried out for the ultra-highly loaded turbine cascade with turning angle of 160 degree in order toclarify the effects of the application of squealer tip and the variation of squealer depth on the reduction ofthe tip leakage vortex. The experimental results clarified that the effects of the application of squealer tipon the reductions of the tip leakage flow and the associated loss depended on the squealer depth.Key Words : Ultra-highly loaded turbine, Linear turbine cascade, Squealer tip, Squealer dept
