Flowfield Measurements in the Endwall Region of a Stator Vane

Kang, M. B.; Thole, Karen A.

doi:10.1115/1.1303703

Cited by 61 publications

(14 citation statements)

References 14 publications

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“…Endwall heat transfer can behave differently compared to a vane surface because of the presence of strong external secondary flows, namely the horseshoe and passage vortices. The passage vortices affect the endwall by skewing the direction of endwall flow and locally increasing the external heat transfer coefficients as shown by Kang and Thole [7]. The first experimental study for a conjugate endwall exposed to passage flows was completed by Mensch and Thole [2].…”

Section: Relevant Literaturementioning

confidence: 99%

Conjugate Heat Transfer Measurements and Predictions of a Blade Endwall With a Thermal Barrier Coating

Mensch

Thole

Craven

2014

Journal of Turbomachinery

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Multiple thermal protection techniques, including thermal barrier coatings (TBCs), internal cooling and external cooling, are employed for gas turbine components to reduce metal temperatures and extend component life. Understanding the interaction of these cooling methods, in particular, provides valuable information for the design stage. The current study builds upon a conjugate heat transfer model of a blade endwall to examine the impact of a TBC on the cooling performance. The experimental data with and without TBC are compared to results from conjugate computational fluid dynamics (CFD) simulations. The cases considered include internal impingement jet cooling and film cooling at different blowing ratios with and without a TBC. Experimental and computational results indicate the TBC has a profound effect, reducing scaled wall temperatures for all cases. The TBC effect is shown to be more significant than the effect of increasing blowing ratio. The computational results, which agree fairly well to the experimental results, are used to explain why the improvement with TBC increases with blowing ratio. Additionally, the computational results reveal significant temperature gradients within the endwall, and information on the flow behavior within the impingement channel.

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Section: Relevant Literaturementioning

confidence: 99%

Conjugate Heat Transfer Measurements and Predictions of a Blade Endwall With a Thermal Barrier Coating

Mensch

Thole

Craven

2014

Journal of Turbomachinery

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“…The external heat transfer for an endwall differs from that of a flat plate, leading edge or airfoil surface, due to the influence of passage secondary flows including the horseshoe and passage vortices. The passage vortices that develop along the endwall skew the direction of endwall flow and locally increase the external heat transfer coefficient, as measured by Kang and Thole [21]. The distribution of the external endwall heat transfer coefficients for the airfoil geometry in this study was investigated by Lynch et al [22] through both experiments and computational predictions with a constant wall heat flux boundary condition.…”

Section: Relevant Literaturementioning

confidence: 75%

Conjugate heat transfer analysis of the effects of impingement channel height for a turbine blade endwall

Mensch

Thole

2015

International Journal of Heat and Mass Transfer

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Advancements in cooling for applications such as gas turbines components require improved understanding of the complex heat transfer mechanisms and the interactions between those mechanisms. Critical cooling applications often rely on multiple thermal protection techniques, including internal cooling and external film cooling in gas turbine airfoils, to efficiently cool components and limit the use of coolant. Most research to quantify the effectiveness of such cooling technologies for gas turbine applications has isolated internal and external cooling in separate experiments. The research presented in this paper uses a conjugate heat transfer approach to account for the combined effects of both internal and external cooling. The geometry used for this study is a turbine blade endwall that includes impingement and film cooling as well as the relevant conduction through the endwall. Appropriate geometric and flow parameters were scaled to ensure engine relevant dimensionless temperatures were obtained. Using the conjugate heat transfer approach, the effect of varying the height of the impingement channel was examined using spatially resolved external wall temperatures obtained from both experiments and simulations. A one-dimensional heat transfer analysis was used to derive the average internal heat transfer coefficients from the experimental results. Both experiments and simulations showed good agreement between area averaged cooling effectiveness and impingement heat transfer coefficients. The cooling effectiveness and heat transfer coefficients peaked for an impingement channel height of around three impingement hole diameters. However, the heat transfer coefficients were more sensitive than the overall effectiveness to the changes in height of the impingement channel.

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“…Most research conducted under unsteady flow conditions focused on the combustor exit flow field and its influence on the aerothermal turbine performance. 85 Kerrebrock and Mikolajczak 86 described the positive/negative jet effects generated by the nonuniform turbine inlet pressures, temperature fields, and the relative motion of the stator and rotor blades. Ong and Miller 87 and Sipatov et al 79 observed the mechanism of redistribution of hot and cold gas regions in the rotor passage.…”

Section: Unsteady Convective Heat Transfer Modelmentioning

confidence: 99%

Modelling of heat transfer and fluid flow in the hot section of gas turbines used in power generation: A comprehensive survey

2018

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Summary Power generation is one of the major industries or businesses globally. Although, at present, a major attention has been paid towards the sustainable energy technologies, both gas and steam turbines are still heavily used in the power generation sector worldwide. Usually, gas turbines are used to drive an electrical power generator in simple systems, or they are used in combined cycle plants together with steam turbines. This paper presents a comprehensive review on modelling of heat transfer and fluid flow in hot section of gas turbines used in the power generation sector. Visibly, heat transfer and fluid flow characteristics directly affect the thermal efficiency and the overall performance of the gas turbines. Hence, existing models relating to heat transfer and fluid flow inside gas turbines are discussed in detail. Primarily, methods relating to the first principle modelling, empirical modelling, and finite element modelling are reviewed comprehensively, and then, a discussion is provided together with a comparison among models in terms of their advantages and disadvantages. Moreover, some existing issues such as the environmental impact are discussed which still remain as challenges to the power generation industry together with some of the possible future directions for improvements.

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Flowfield Measurements in the Endwall Region of a Stator Vane

Cited by 61 publications

References 14 publications

Conjugate Heat Transfer Measurements and Predictions of a Blade Endwall With a Thermal Barrier Coating

Conjugate Heat Transfer Measurements and Predictions of a Blade Endwall With a Thermal Barrier Coating

Conjugate heat transfer analysis of the effects of impingement channel height for a turbine blade endwall

Modelling of heat transfer and fluid flow in the hot section of gas turbines used in power generation: A comprehensive survey

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