The feature of tip-leakage vortex breakdown and the stability mechanism were analyzed and summarized using the first-stage rotor blade of GE-E3 turbine. The study indicated that: the breakdown of tip-leakage vortex core was caused by vortexs centrifugal instability; the vortex core expanded rapidly after losing stability and reversed flow was formed; the vortex core stability depended on two factors: swirling number and reversed pressure gradient. After that

the control of tip-leakage loss was carried out from the perspective of vortex core stability. Calculations show that: moving forward the loading of tip blade profile can reduce the pressure gradient; employing straight profile on the suction surface after passage throat can directly decrease the profile diffuse factor; and the redesigned blade by those two methods can obviously weaken the tip-leakage vortex

suppress the instability of vortex core and decrease the tip-leakage losses.