Topic
Tip clearance
About: Tip clearance is a research topic. Over the lifetime, 2637 publications have been published within this topic receiving 32671 citations.
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TL;DR: In this article, the variation laws of exciting force, pressure coefficient and the hydrodynamic coefficients differences have been studied at the different tip clearances and different oblique flow angle, and the time domain data of the pulsating pressure of PJP with cavitation conditions or without cavitation condition was presented, and then which was converted to frequency domain data by fast Fourier transform (FFT).
26 citations
08 May 2000
TL;DR: In this paper, an investigation of the overtip end-wall flow in a single-stage axial-flow low-speed compressor utilizing an oil flow technique and a periodic multisampling pressure measurement technique is presented.
Abstract: The paper describes an investigation of the overtip end-wall flow in a single–stage axial–flow low–speed compressor utilizing an oil flow technique and a periodic multisampling pressure measurement technique. Representative oil flow pictures and ensemble averaged casingwall pressure distributions with standard deviations — supplemented by selected endwall oil flow pictures from a corresponding 2D compressor cascade — are shown and carefully analysed. The results enable the key features of the overtip endwall flow to be identified and changes with flow rate — or inlet angle — to be determined.Copyright © 2000 by ASME
25 citations
Patent•
02 Mar 2007TL;DR: An axial fan assembly including a casing wall with a forward facing step formed therein and a fan rotor with blade tips, each having an aft facing step which radially overlaps the casing step so as to reduce the clearance backflow loss in the assembly as discussed by the authors.
Abstract: An axial fan assembly including a casing wall with a forward facing step formed therein and a fan rotor with blade tips, each having an aft facing step which radially overlaps the casing step so as to reduce the clearance backflow loss in the assembly. A vane is attached to the suction side of each of the blade tips with the vane having an aft facing step which radially overlaps the casing forward facing step to promote further reduction of clearance backflow. Variations on the invention include the option of an additional inlet bellmouth piece that further restricts the clearance flow and wedges integral to the casing step to improved flow stability.
25 citations
14 Jan 2002
TL;DR: In this article, numerical flow simulations for a transonic axial compressor are conducted using an existing flow solver, and detailed analyses are performed concerning tip-vortex development and topology as well as shockvortex interaction.
Abstract: A great potential regarding powerful loss reduction in transonic axial flow compressors is located at the tips of the blades. In this region, losses are intensified by tip-vortices standing above the suction sides of the blades. Each vortex propagates through the blade duct in question and must cross the passage shock which is caused by the flow deflection of the neighboring blade. The shock-vortex-interaction leads to a sudden and strong deceleration of the flow and, as consequence, to a strong change in the vorticity distribution of the vortex. Depending on the intensity of the shock-vortex-interaction, vortex breakdown can occur inducing compressor surge. In order to clarify these phenomena it is necessary to analyze the flow field in the tip region. For that purpose, numerical flow simulations for a transonic axial compressor are conducted using an existing flow solver. Detailed analyses are performed concerning tip-vortex development and topology as well as shock-vortex- interaction.
25 citations
Patent•
09 Mar 2011TL;DR: In this paper, a gas turbine engine and a method of operating the gas turbine engines is described, where the engine has a row of circumferentially spaced rotor blades, each having a radially outer tip.
Abstract: A gas turbine engine and a method of operating the gas turbine engine is provided. The gas turbine engine has a row of circumferentially spaced rotor blades (32), each having a radially outer tip. The engine further has a plurality of seal segments (33) circumscribing the rotor blade tips and attached to a radially inward side of a casing (1) of the engine. The seal segments are spaced from the casing by a spacing cavity (B). In use, a flow of relatively hot cooling air is routed to the spacing cavity to provide cooling for the seal segments. The engine further has an external cooling arrangement for impinging relatively cold cooling air on a radially outward side of the casing and thereby controlling a radial clearance (G) between the rotor blade tips and the seal segments. The engine further has a wall (39) containing a plurality of through-holes (40) which is attached to a radially inward side of the casing adjacent the seal segments. The wall is spaced from the casing to define a heating control chamber (E) between the wall and the casing. The engine further has one or more closable ducts (41) which allow air to be exhausted from the heating control chamber. When the ducts are open, a portion of the hot cooling air flows through the through-holes to impinge on the casing and then exhausts from the heating control chamber through the ducts.
25 citations