Detailed Heat Transfer Coefficient Distributions on a Large-Scale Gas Turbine Blade Tip

Teng, Shuye; Han, Je-Chin; Azad, G.M.S.

doi:10.1115/1.1373655

Cited by 42 publications

(6 citation statements)

References 24 publications

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“…Another common observation, largely based on well-established experimental results at low speed conditions, is a close "correspondence" between aerodynamic loss and heat transfer: larger tip gaps result in more OTL loss, and higher heat transfer (Teng et al, 2001). In a simple and basic term, this should be regarded as being in keeping with the Reynolds analogy.…”

Section: Background and Conventional Wisdommentioning

confidence: 98%

Turbine blade tip aero-thermal management: Some recent advances and research outlook

Zhang

2017

J. Glob. Power Propuls. Soc.

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This article provides an overview of some recent progress in understanding HP turbine blade shroudless tip heat transfer and aerodynamics, especially in a transonic regime. The review is mostly based on the experimental and numerical efforts the authors have been involved in during the past ten years. Some fundamental flow physics especially in high speed Over-Tip-Leakage (OTL) flows are highlighted, including tip choking, shock waves, and the roles played by flow turbulence, etc. These mechanisms bring qualitative differences in tip heat transfer and loss generation, and prospects in tip aerothermal management and control. Of great interest is the strong OTL flow–coolant interaction, which can dramatically affect the tip aerodynamics, and thus would challenge any “optimized” tip geometry based on an uncooled configuration. It is suggested that optimal tip aero-thermal configurations should be an iterative process between blade tip shaping and cooling injection scheme. Combining tip geometry shaping and cooling injection patterns concurrently may provide more extensive exploitation of tip aerothermal design space.

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Section: Background and Conventional Wisdommentioning

confidence: 98%

Turbine blade tip aero-thermal management: Some recent advances and research outlook

Zhang

2017

J. Glob. Power Propuls. Soc.

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“…For instance, Tang et al. 9 and Newton et al. 10 carried out studies on aerodynamics and heat transfer of the turbine blade tip.…”

Section: Introductionmentioning

confidence: 99%

Parametric study of injection from the casing in an axial turbine

Abbasi

Gholamalipour

2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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Tip leakage flow reduces both efficiency and performance of axial turbines and damages turbine blades as well. Therefore, it is of great importance to identify and control tip leakage flow. This study investigated the effect of flow injection (from the casing), alongside flow structure, on turbine performance. Additionally, the effect of different injection parameters, including injection mass flow rate, angle, location, and diameter on the turbine performance are evaluated. A numerical analysis of the flow in a two-stage axial turbine was employed by using CFX software. To ensure the accuracy of the results, turbine performance curves were compared with the experimental results, which are in good agreement. Analyses revealed that active control method reduces tip leakage flow, improves turbine performance, and increases the efficiency by 1% to 5% as well. A parametric investigation of the tip injection has sought to identify how various parameters affect the turbine performance. The cross-section diameter and the angle of injection had no significant increase on efficiency. Additionally, results showed that at a point 9 mm further from the leading edge, the injection degree of effectiveness is optimum. Finally, analysis of the flow structure in the tip clearance region supported the tip leakage flow reduction.

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“…A number of studies related to the flat tips or the squealer tips were published (e.g. Azad et al, 2000;Bunker and Bailey, 2001;Teng et al, 2001;Kwak and Han, 2003;Newton et al, 2006). Fewer studies focus on the heat transfer of the squealer-winglet tips.…”

Section: Introductionmentioning

confidence: 99%

Tip gap size effects on thermal performance of cavity-winglet tips in transonic turbine cascade with endwall motion

Zhong

Zhou

2017

J. Glob. Power Propuls. Soc.

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The thermal performance of two cavity-winglet tips with endwall motion is investigated in a transonic high pressure turbine cascade, which operates at an engine representative exit Mach number of 1.2 and an exit Reynolds number of 1.7 × 106. The numerical method is first validated with experimental data and then used to investigate blade heat transfer at three different tip clearances of 1.1, 2.1 and 3.1% chord. The effects of relative endwall motion are considered. The present results show that as the size of the tip gap increases, the heat transfer coefficient and heat load on the tip increases. The winglet geometries on the blade tip mainly affect the tip flow structure close to them. At a larger tip clearance, the size of the separation bubble above the pressure side winglet increases. The heat transfer coefficient is high on the pressure side winglet due to the flow reattachment at all tip clearances. Within the tip gap, when the size of the tip clearance increases, the size of the cavity vortex increases and the cavity scraping vortex due to relative endwall motion becomes smaller. The impingement of the both two vortexes can lead to high heat transfer coefficient on the cavity floor surface. On the blade suction surface, when the size of the tip clearance increases, the heat transfer coefficient of the cavity tip increases, but those of the winglet tips decreases. The heat transfer coefficient is high on the side surface of the suction side winglet at all tip clearances because of the tip leakage flow impingement.

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Detailed Heat Transfer Coefficient Distributions on a Large-Scale Gas Turbine Blade Tip

Cited by 42 publications

References 24 publications

Turbine blade tip aero-thermal management: Some recent advances and research outlook

Turbine blade tip aero-thermal management: Some recent advances and research outlook

Parametric study of injection from the casing in an axial turbine

Tip gap size effects on thermal performance of cavity-winglet tips in transonic turbine cascade with endwall motion

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