Journal ArticleDOI
Reduction of Tip Clearance Losses in an Unshrouded Turbine by Rotor Casing Contouring
Jie Gao,Qun Zheng,Guoqiang Yu +2 more
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In this article, the effect of three types of casing contouring, step, trench, and arc casings, on aerodynamic performance of an unshrouded turbine rotor at design and off-design incidences was investigated.Abstract:
Tip leakage flow is responsible for a number of aerodynamic losses in turbines, and the mixing of tip leakage flow with the passage secondaryflowcauses significant losses. This paperpresents a numerical investigation of the effect of three types of casing contouring: 1) step, 2) trench, and 3) arc casings on aerodynamic performance of anunshrouded turbine rotor at design and off-design incidences, in an attempt to seek an optimal casing contour with the objective both of avoiding direct tip leakage in the tip clearance, and of efficiently using the interaction between the tip leakage vortex and passage vortex inside rotor passage, and then to reduce the total losses in turbines. The results show that the reduction in tip leakage losses obtained by the optimized casing contour significantly overrides the losses caused by the step in theflowpath. Introduction of casing step thickens the inlet boundary layer, which increases the strength of the tip passage vortex and hence suppresses the evolution of the tip leakage vortex. Step and trench casings provide the largest efficiency increase when the inlet flow direction is normal to the casing step while arc casing achieves the best performance improvement at the design incidence.read more
Citations
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Journal ArticleDOI
Aerothermal characteristics of a transonic tip flow in a turbine cascade with tip clearance variations
TL;DR: In this paper, the authors investigated the sensitivity of aerothermal performance of transonic tip flows to tip clearances in a RT27a turbine cascade, and they used the ANSYS CFX 14.5 numerical prediction code, adopting the SST k-ω turbulence model.
Journal ArticleDOI
Casing grooves to improve aerodynamic performance of a HP turbine blade
TL;DR: In this article, the effect of groove type casing treatment on the aerodynamic performance of a linear turbine cascade was investigated using the computational approach for a single-stage axial turbine blade.
Journal ArticleDOI
Inlet conditions effect on tip leakage vortex breakdown in unshrouded axial turbines
TL;DR: In this paper, the effects of inlet conditions on the tip leakage vortex dynamics in an unshrouded turbine were investigated, and a comparison of effects of different inlet condition on tip leakage mixing loss was examined.
Journal ArticleDOI
Advances in aerodynamic, structural design and test technology of variable geometry turbines
TL;DR: This paper summarizes and analyzes the recent advances in the field of aerodynamic, structural design and test of variable geometry turbines, and places the emphasis on the variable vane turning design method.
Journal ArticleDOI
Aero-thermal performance improvements of unshrouded turbines through management of tip leakage and injection flows
TL;DR: In this article, a numerical investigation of tip injection on aero-thermal performance of the tip leakage flow for both flat tip and cavity tip in an unshrouded turbine rotor is presented.
References
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Journal ArticleDOI
Two-equation eddy-viscosity turbulence models for engineering applications
TL;DR: In this paper, two new two-equation eddy-viscosity turbulence models are presented, which combine different elements of existing models that are considered superior to their alternatives.
Journal ArticleDOI
The measurement and formation of tip clearance loss
TL;DR: In this article, the tip clearance loss from the leading to trailing edge of a linear turbine cascade was measured and the contributions made by mixing, internal gap shear flow, and endwall/secondary flow were identified, separated, and quantified for the first time.
Journal ArticleDOI
Axial Turbine Blade Tips: Function, Design, and Durability
TL;DR: An overview of the science and technology involved in today's turbine engines is presented with specific focus on the critical rotational-to-stationary interfaces comprising axial turbine blade tips as discussed by the authors.
Journal ArticleDOI
A Review of Turbine Blade Tip Heat Transfer
TL;DR: A review of the publicly available knowledge base concerning turbine blade tip heat transfer, from the early fundamental research which laid the foundations of knowledge, to current experimental and numerical studies utilizing engine‐scaled blade cascades and turbine rigs.
Proceedings ArticleDOI
Comparison of Turbine Tip Leakage Flow for Flat Tip and Squealer Tip Geometries at High-Speed Conditions
Nicole L. Key,Tony Arts +1 more
TL;DR: In this paper, the authors studied the tip leakage flow characteristics for flat and squealer turbine tip geometries in the von Karman Institute Isentropic Light Piston Compression Tube facility, CT-2, at different Reynolds and Mach number conditions.