Unsteady Aerodynamics of a Flat Tip and a Winglet Tip in a High-Pressure   Turbine

CORC > 北京大学 > 工学院

	Unsteady Aerodynamics of a Flat Tip and a Winglet Tip in a High-Pressure Turbine
	Zhou, Kai ; Zhou, Chao
	2016
关键词	AXIAL-FLOW TURBINE ROTOR
英文摘要	In an unshrouded high-pressure turbine, tip leakage flow results in a loss of efficiency. In this paper, the aerodynamic performance of the tip leakage flow is investigated in a turbine stage by numerical methods. A flat tip and a closed squealer tip combined with a suction side winglet are used for the rotor tips, and the two turbines are named as 'Flat Configuration' and 'Winglet Configuration'. The ability of the CFD methods in predicting the unsteady flow and the tip leakage flow is validated. The steady calculations using a mixing plane between the stator and the rotor are presented first. Then, the unsteady flows of the turbine stage with a flat rotor tip and a winglet rotor tip are simulated by solving Unsteady Reynolds Averaged Navier-Stokes (URANS) equations. Compared with the 'Flat Configuration', the 'Winglet Configuration' reduces the size of the passage vortex and the tip leakage vortex. A surprising observation is that although the 'Winglet Configuration' reduces the size of the tip leakage vortex, its maximum swirl strength of the tip leakage vortex is about 40% higher than that for the 'Flat Configuration'. The steady calculation shows that the entropy generation for the turbine stage is 12.1% lower with the 'Winglet Configuration' than that with the 'Flat Configuration'. The mixed-out entropy predicted in the unsteady calculation is higher than that of the steady calculation for both tips. The stator casing passage vortex has a periodic effect on the vortex near the tip gap of the rotor. The unsteady interaction of the vortices seems to be beneficial in terms of the loss. As a result, the 'Winglet Configuration' produces 9.4% less entropy than the 'Flat Configuration', which is lower than that in the case of the steady calculation.; CPCI-S(ISTP); kinozhou@pku.edu.cn; czhou@pku.edu.cn
会议录	ASME Turbo Expo: Turbine Technical Conference and Exposition
语种	英语
内容类型	会议论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/460203]
专题	工学院
推荐引用方式 GB/T 7714	Zhou, Kai,Zhou, Chao. Unsteady Aerodynamics of a Flat Tip and a Winglet Tip in a High-Pressure Turbine[C]. 见:.