An innovative passive tip-leakage control method for axial turbines: Basic concept and performance potential

Hamik, Markus; Willinger, Reinhard

doi:10.1007/s11630-007-0215-y

Cited by 13 publications

(4 citation statements)

References 13 publications

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“…Bunker’s study 3 found that the tip clearance flow occurring in rotor blade rows was responsible for about one-third of the aerodynamic losses in the blade rows. Hamik and Willinger 4 argued that the energy loss mixed between leakage fluid in tip clearance and the main flow in the cascade passage was a major component of tip clearance loss. Therefore, it is of great significance to research the relationship between the blade tip shape and the relevant aerodynamic parameters in order to control the leakage flow.…”

Section: Introductionmentioning

confidence: 99%

Modification and optimization strategies for turbine arbitrary blade tips

Jin

Song

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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The influence of different arbitrary blade tip shapes on restraining the tip leakage flow in a highly loaded turbine cascade has been numerically studied. A combined method of establishing and optimizing the arbitrary blade tip shape is proposed by using B-spline surface modeling, Kriging model and genetic optimization algorithm. The results show that the Kriging model established by the B-spline surface modeling method can accurately fit the relationship between the arbitrary blade tip shape and the relevant aerodynamic parameters. The optimal leakage mass flow tip and the optimal total pressure loss tip obtained by genetic algorithm both have strong inhibitory effects on tip leakage flow. Compare to the flat tip at 1%H gap height, the tip leakage mass flow of the optimal leakage mass flow case and the optimal total pressure loss case decrease by 11.14% and 10.23%, respectively, the area-average total pressure loss at exit section is reduced by 8.08% and 7.41%, respectively.

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Section: Introductionmentioning

confidence: 99%

Modification and optimization strategies for turbine arbitrary blade tips

Jin

Song

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Hamik and Willinger 34 analytically and numerically investigated the concept patented by Auxier 35 in 1995. The idea consists in connecting the blade leading edge to the blade tip by an internal channel.…”

Section: Introductionmentioning

confidence: 99%

“…They succeeded to increase the efficiency by 0.35% with loose tip clearance, and by 0.3% with tight tip clearance. Hamik and Willinger (12) analytically and numerically investigated the concept patented by Auxier (13) in 1995. The idea is to connect the blade leading edge to the blade tip by an internal channel.…”

mentioning

confidence: 99%

Experimental investigation of an actively controlled automotive cooling fan using steady air injection in the leakage gap

Azzam

Paridaens

Ravelet

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part A:

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International audiencen an axial fan, a leakage flow driven by a pressure gradient between the pressure side and the suction side occurs in the gap between the shroud and the casing. This leakage flow is in the opposite direction to the main flow and is responsible for significant energy dissipation. Therefore, many authors have worked to understand this phenomenon in order to reduce these inherent energy losses. Up to now, most of the studies reported in the literature have been passive solutions. In this paper, an experimental controlling strategy is suggested to reduce the leakage flow rate. To this end, a fan with hollow blades and a specific drive system were designed and built for air injection. Air is injected in the leakage gap at the fan periphery. The experiment was performed for three rotation speeds, five injection rates and two configurations: 16 and 32 injection holes on the fan's circumference. The experimental results of this investigation are presented in this articl

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“…Newton et al [9] measured the heat transfer coefficient on the tip of a generic cooled turbine blade and confirmed the reduction of heat flux to the blade tip regions. Hamik and Willinger [10] connected the blade leading edge and the blade tip surface using an internal channel; therefore, a small part of passage flow was injected from the blade tip surface forced by the pressure difference. They found that tip injection could reduce flow over-under-turning near the casing wall, as well as the losses due to the tip clearance vortex.…”

Section: Introductionmentioning

confidence: 99%

Parametric study of tip cooling injection in an axial turbine cascade: Influences of injection circumferential angle

Niu

Zang

2009

Proceedings of the Institution of Mechanical Engineers, Part A:

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This article presents a parametric investigation of an innovative tip-clearance control method. Cooling air is injected into the tip clearance to obstruct tip clearance flow, from the blade tip surface through a row of 11 equidistant holes. In order to demonstrate the influences of injection circumferential angle, four different test cases are performed and compared with the baseline case without air injection. The results indicate that injection circumferential angle plays an important role in the redistribution of secondary flow within the cascade passage. Injection at a smaller circumferential angle performs better in reducing tip clearance mass flow and its associated losses. However, it also intensifies the tip passage vortex much more, because of the reduced restraint deriving from the weaker tip clearance vortex. It can also be found that flow under-turning caused by the tip clearance vortex can be reduced greatly with a smaller circumferential angle. But the heat transfer condition is worse than that when cooling air is injected perpendicularly to the blade tip surface. Besides that, a modified tip clearance loss model is observed to be able to perform well in predicting the losses induced by tip clearance flow at all the conditions considered in this article.

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An innovative passive tip-leakage control method for axial turbines: Basic concept and performance potential

Cited by 13 publications

References 13 publications

Modification and optimization strategies for turbine arbitrary blade tips

Modification and optimization strategies for turbine arbitrary blade tips

Experimental investigation of an actively controlled automotive cooling fan using steady air injection in the leakage gap

Parametric study of tip cooling injection in an axial turbine cascade: Influences of injection circumferential angle

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