Numerical investigation of active tip-clearance control through tip cooling injection in an axial turbine cascade

Niu, Maosheng; Zang, Shusheng

doi:10.1007/s11630-009-0306-z

Cited by 8 publications

(4 citation statements)

References 15 publications

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“…This is somewhat surprising, since both planes 1 and 2 are downstream of the jet injection locations at holes 3 and 4. The vortex still clearly forms, but perhaps the jets divert the leakage flow to a more downstream location, delaying the formation of the vortex, as observed by Niu and Zang [12], and this delay results in lower total pressure drop.…”

Section: Resultsmentioning

confidence: 84%

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Control of Tip Leakage in a High-Pressure Turbine Cascade Using Tip Blowing

Volino

2017

Journal of Turbomachinery

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Blowing from the tip of a turbine blade was studied experimentally to determine if total pressure loss could be reduced. Experiments were done with a linear cascade in a low-speed wind tunnel. Total pressure drop through the blade row and secondary velocity fields in the passage between two blades were measured. Cases were documented with various blowing hole configurations on flat and squealer tipped blades. Blowing normal to the tip was not helpful and in some cases increased losses. Blowing from the bottom of a squealer cavity provided little benefit. With a flat tip, blowing from holes located near and inclined toward the pressure side generally reduced total pressure drop by reducing the effect of the tip leakage vortex. Holes near the axial location of maximum loading were most helpful, while holes closer to the leading and trailing edges were not as effective. Higher jet velocity resulted in larger total pressure drop reduction. With a tip gap of 1.5% of axial chord, jets with a velocity 1.5 times the cascade inlet velocity had a significant effect. A total pressure drop reduction of the order 20% was possible using a jet mass flow of about 0.4% of the main flow. Jets were most effective with smaller tip gaps, as they were more able to counter the leakage flow.

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Section: Resultsmentioning

confidence: 84%

“…They reported a reduction in total pressure loss, but the jet velocities required appear to be higher than achievable in an engine. Niu and Zang [12] conducted a numerical study of blowing from the tip. They used rows of holes inclined toward the pressure side.…”

Section: Introductionmentioning

confidence: 99%

Control of Tip Leakage in a High-Pressure Turbine Cascade Using Tip Blowing

Volino

2017

Journal of Turbomachinery

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“…The engine's tip clearance is at its lowest in the accelerated transition state, which makes friction failure easy to happen, according to the literature study [14][15][16]. It is known that the working speed of a typical engine in slow running conditions is approximately 9000RPM based on the relation diagram between time and speed in each typical working condition provided by MTU technical manual and literature [17]. The author equalized the speed in the acceleration process and chose three different speeds within the range of 3000RPM, 6000RPM, and 9000RPM for research.…”

Section: Rotational Speedmentioning

confidence: 99%

Friction Thermal Effect Analysis of High Pressure Turbine Rubbing in Aero-Engine

Zhang,

Yang,

Meng

2023

Advances in Transdisciplinary Engineering

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When the high-pressure turbine of an aero-engine comes into contact with friction, the friction-heat effect that results raises the temperature at the site of contact quickly. In extreme circumstances, it will harm the blades and casing and impair the engine’s ability to function properly. A vane-casing thermo-solid coupling model was developed using the finite element method to study the impact of the frictional heat effect on local details at the contact point. The distribution rules of blade temperature and stress were examined when the rotational speed changed and whether the coating was applied to the casing inner surface. The findings indicate that there is a temperature asymmetry between the blade and casing and that the rubbing friction heat effect is primarily distributed on the contact surface between the blade and casing. The influence area is also small and will rise to a high temperature in a very short period. Temperature and stress are impacted by variations in rotational speed and the use of coatings. The temperature and stress peaks at blade contact can be greatly decreased by coating the inside surface of the casing. The frictional heat effect created by rubbing should be taken into account in real-world engineering issues.

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“…The tip injection at 81% blade axial chord was most successful in reducing the total pressure deficit in the leakage vortex. Niu and Zang 25–27 performed parametric investigations of the tip injection in a high-turning axial turbine cascade, including injection circumferential angle and injection location in the blade-thickness direction. The results showed that, the nearer the injection holes are to the pressure side (PS) corner and the smaller the injection circumferential angle is, the more tip injection can affect the tip leakage flow.…”

Section: Introductionmentioning

confidence: 99%

Reduction of turbine tip clearance losses at design and off-design incidences by non-uniform tip injection

Gao

Zheng

Liu

et al. 2014

Proceedings of the Institution of Mechanical Engineers, Part A:

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Tip injection has shown potential for controlling turbine tip clearance flows; however, the effects of tip injection may behave differently at design and off-design incidences. This paper computationally investigates the sensitivity of endwall flowfields and aerodynamics to flow incidence for flat and cavity tips at different injection locations, in an attempt to explore the potential of further reduction of tip clearance losses at various incidences by non-uniform tip injection concept. First, a linear cascade validation is introduced, and the computations were compared with the experimental data to identify the ability of the computational fluid dynamics (CFD) code to predict the tip leakage flow. Flow patterns over the blade tip without injection (WI) at different incidences were shown, and then the sensitivity of endwall flowfields and aerodynamics to incidence at different injection locations was investigated. Also, the effects of non-uniform tip injection on aerodynamic performance at design and off-design incidences were examined. The results show that the injection in the front part performs better performance than that in the rear part, while it causes turbine performance to be more sensitive to flow incidence than the injection in the rear part. Compared to the flat tip, the coupling effect between cavity tip and tip injection reduces the sensitivity of turbine performance to incidence variation. The non-uniform tip injection, which takes into account the tip leakage flow mechanisms at different incidences, optimizes the mixing process between the tip clearance flow and the passage flow, further improving the design and off-design performance of turbines.

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Numerical investigation of active tip-clearance control through tip cooling injection in an axial turbine cascade

Cited by 8 publications

References 15 publications

Control of Tip Leakage in a High-Pressure Turbine Cascade Using Tip Blowing

Control of Tip Leakage in a High-Pressure Turbine Cascade Using Tip Blowing

Friction Thermal Effect Analysis of High Pressure Turbine Rubbing in Aero-Engine

Reduction of turbine tip clearance losses at design and off-design incidences by non-uniform tip injection

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