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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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Proceedings ArticleDOI
12 Mar 1979
TL;DR: In this article, the 3-D viscous flow computer program was used to optimize the low-aspect-ratio stator of a high-work turbine stage, in conjunction with the radial distribution of energy extraction, led to innovative but realistic blading for advanced gas generator turbines.
Abstract: Previously reported cascade test results verified and provided a calibration of the 3-D viscous flow analysis. This paper describes the subsequent AFAPL-sponsored technology program in which the 3-D viscous flow computer program was used to optimize the low-aspect-ratio stator of a high-work turbine stage. The optimization procedure, in conjunction with the radial distribution of energy extraction, led to innovative-but-realistic blading for advanced gas generator turbines. A turbine stage was tested with this stator, in conjunction with an appropriate rotor design. The total-to-total design-point efficiency — 92 percent at 1-percent tip clearance — was achieved at 31.83 Btu/lbm specific work. In addition to stage tests, separate stator tests were conducted including a measurement of total pressure loss and stator reaction torque, which provided baseline data to assess interaction effects during stage testing with stator reaction measurements “in vivo.”Copyright © 1979 by ASME

13 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of boundary layer suction on the flow characteristic in a highly loaded compressor cascade with a stator clearance are studied experimentally, and two types of clearance including "long clearance" and "short clearance" are considered separately.

13 citations

Proceedings ArticleDOI
01 Jan 2008
TL;DR: In this paper, the secondary flow in the tip clearance region of a stationary linear low pressure turbine blade cascade was studied using two types of surface flow visualization and documented using wake pressure measurements in order to identify the potential means and impact of flow control to reduce losses associated with tip clearance flow.
Abstract: The secondary flow in the tip clearance region of a stationary linear low pressure turbine blade cascade was studied using two types of surface flow visualization and documented using wake pressure measurements in order to identify the potential means and impact of flow control to reduce losses associated with the tip clearance flow. An evaporating fluid mixture was used for flow visualization on the casing surface of the tip clearance. An oil ink-dot tracing method was used on the blade tip. These measurements illustrate the important features of the near-casing flow physics, including the size and chordwise extent of the blade tip separation bubble, separation lines on the casing, the flow direction on the blade tip and casing, the size and exit trajectory of the tip leakage and passage vortices, as well as the total pressure loss and secondary velocity vectors downstream of the blade. The flow was visualized in this way for a plain, flat tip, a tip mounted plasma actuator, and a partial suction side squealer tip. Both flow control devices were observed to affect the flow in the clearance. The plasma actuator was shown to improve the total pressure loss in the tip leakage vortex by as much as 9% from the loss over the plain tip blade. The tests were performed over a Reynolds numbers range between 5.3 × 104 and 1.04 × 105 at a fixed tip clearance of 2% of axial chord.Copyright © 2008 by ASME

13 citations

Patent
10 May 2007
TL;DR: In this article, the stagnation lines 35 formed at various heights in the heightwise direction of a stationary blade are generally aligned in the rotational direction of the rotor, and fluctuation of pressure distribution in the vertical axis of the stationary blade can be reduced.
Abstract: To reduce secondary flow loss and to improved turbine efficiency, a section located radially outward of a border section 28 of a stationary blade 21 is bent in the rotational direction of a rotor. Thus, even if combustion gas leaks from a tip clearance between an end wall of a casing and a tip portion of a rotor blade, and a stagnation line 35 near a tip portion 22 is situated in the side of a back surface 24, because a section located radially outward of the border section 28 is bent in the rotational direction of the rotor, the stagnation line 35 is also situated toward the rotational direction of the rotor. Therefore, the stagnation lines 35 formed at various heights in the heightwise direction of the stationary blade 21 are generally aligned in the rotational direction of the rotor. Thus, fluctuation of pressure distribution in the heightwise direction of the stationary blade 21, of the combustion gas flowing into the stationary blade 21 can be reduced. As a result, secondary flow loss can be reduced and turbine efficiency can be improved.

13 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202354
2022149
202189
2020111
2019116
201897