An Experimental Study of Heat Transfer and Film Cooling on Low Aspect Ratio Turbine Nozzles

Takeishi, Kenichiro; Matsuura, M.; Aoki, S.; Satō, Tomohiko

doi:10.1115/89-gt-187

Cited by 37 publications

(21 citation statements)

References 10 publications

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“…He found that both heat transfer and film-cooling on the endwall are influenced by secondary flow. A similar observation was made by Takeishi et al (1989). Their leading edge horseshoe vortex, Endwall Static Pressure Contours Without Coolant Ejection (Harrison (1989)) Expressed as (11_, -p)/(11, -p az,)…”

Section: Introductionsupporting

confidence: 69%

Aerodynamic Aspects of Endwall Film-Cooling

Friedrichs

Hodson

Dawes

1997

Journal of Turbomachinery

105

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This paper describes an investigation of the aerodynamic aspects of endwall film-cooling, in which the flow field downstream of a large-scale low-speed linear turbine cascade has been measured. The integrated losses and locations of secondary flow features with and without endwall film-cooling have been determined for variations of both the coolant supply pressure and injection location. Together with previous measurements of adiabatic film-cooling effectiveness and surface-flow visualization, these results reveal the nature of the interactions between the ejected coolant and the flow in the blade passage. Measured hole massflows and a constant static pressure mixing analysis, together with the measured losses, allow the decomposition of the losses into three distinct entropy generation mechanisms: loss generation within the hole, loss generation due to the mixing of the coolant with the mainstream, and change in secondary loss generation in the blade passage. Results show that the loss generation within the coolant holes is substantial and that ejection into regions of low static pressure increases the loss per unit coolant massflow. Ejection upstream of the three-dimensional separation lines on the endwall changes secondary flow and reduces its associated losses. The results show that it is necessary to take the three-dimensional nature of the endwall flow into account in the design of endwall film-cooling configurations.

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Section: Introductionsupporting

confidence: 69%

Aerodynamic Aspects of Endwall Film-Cooling

Friedrichs

Hodson

Dawes

1997

Journal of Turbomachinery

105

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“…Considering the complex flowfield in the rotating rig test, including the vane wakes, a reasonable comparison is very difficult. Film cooling with a rotating rig was experimentally investigated by Dring et al, 48 Abhari and Epstein, 49 and Takeishi et al 50 ; in each case, comparisons to stationary blade configurations were attempted.…”

Section: G Rotating Rig Testsmentioning

confidence: 99%

Gas Turbine Film Cooling

Bogard

Thole

2006

Journal of Propulsion and Power

684

179

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The durability of gas turbine engines is strongly dependent on the component temperatures. For the combustor and turbine airfoils and endwalls, film cooling is used extensively to reduce component temperatures. Film cooling is a cooling method used in virtually all of today's aircraft turbine engines and in many power-generation turbine engines and yet has very difficult phenomena to predict. The interaction of jets-in-crossflow, which is representative of film cooling, results in a shear layer that leads to mixing and a decay in the cooling performance along a surface. This interaction is highly dependent on the jet-to-crossflow mass and momentum flux ratios. Film-cooling performance is difficult to predict because of the inherent complex flowfields along the airfoil component surfaces in turbine engines. Film cooling is applied to nearly all of the external surfaces associated with the airfoils that are exposed to the hot combustion gasses such as the leading edges, main bodies, blade tips, and endwalls. In a review of the literature, it was found that there are strong effects of freestream turbulence, surface curvature, and hole shape on the performance of film cooling. Film cooling is reviewed through a discussion of the analyses methodologies, a physical description, and the various influences on film-cooling performance. Dr. David Bogard is a Professor of Mechanical Engineering at the University of Texas at Austin, and holds the John E. Kasch Fellow in Engineering. He received his B.S. and M.S. degrees in mechanical engineering from Oklahoma State University, and his Ph.D. from Purdue University. He has served on the faculty at the University of Texas since 1982. Dr. Bogard has been active in gas turbine cooling research since 1986, and has published over 100 peer-reviewed papers. He was awarded the ASME Heat Transfer Committee Best Paper Award in 1990 and 2003, and is a fellow of the ASME. Dr. Karen Thole holds the William S. Cross Professorship of Mechanical Engineering at Virginia Polytechnic Institute and State University. She received her B.S. and M.S. degrees in mechanical engineering from the University of Illinois, and a Ph.D. from the University of Texas at Austin. She spent two years as a postdoctoral researcher at the Institute for Thermal Turbomachinery at the University of Karslruhe in Germany and in 1994 she accepted a faculty position at the University of Wisconsin-Madison. In 1999, she became a faculty member in the Mechanical Engineering Department at Virginia Polytechnic Institute and State University where she was promoted to professor in 2003. She received the National Science Foundation CAREER Award in 1996, which was directed at developing a better understanding of gas turbine heat transfer. Dr. Thole's areas of expertise are heat transfer and fluid mechanics specializing in turbulent boundary layers, convective heat transfer, and high freestream turbulence effects. She has published more than 80 peer-reviewed papers and has advised over 30 graduate theses.

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“…Coolant ejection locations have to be viewed with respect to the three-dimensional separation lines on the endwall, taking account of the fact that these can be changed due to upstream endwall coolant ejection. Previous investigations of endwall filmcooling, such as the ones by Blair (1974), Takeishi et al (1989), Granser and Schulenberg (1990), Bourguignon (1985), Bario et al (1989), Harasgama and Burton (1991), Jabbari et al (1994), Goldman and McLallin (1977) and Sieverding and Wilputte (1980) support these conclusions.…”

Section: Introductionmentioning

confidence: 60%

The Design of an Improved Endwall Film-Cooling Configuration

Friedrichs

Hodson

Dawes

1998

Volume 4: Heat Transfer; Electric Power; Industrial and Cogeneration

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The endwall film-cooling cooling configuration investigated by Friedrichs et al. (1996, 1997) had in principle sufficient cooling flow for the endwall, but in practice, the redistribution of this coolant by secondary flows left large endwall areas uncooled. This paper describes the attempt to improve upon this datum cooling configuration by redistributing the available coolant to provide a better coolant coverage on the endwall surface, whilst keeping the associated aerodynamic losses small. The design of the new, improved cooling configuration was based on the understanding of endwall film-cooling described by Friedrichs et al. (1996, 1997). Computational fluid dynamics were used to predict the basic flow and pressure field without coolant ejection. Using this as a basis, the above described understanding was used to place cooling holes so that they would provide the necessary cooling coverage at minimal aerodynamic penalty. The simple analytical modelling developed in Friedrichs et al. (1997) was then used to check that the coolant consumption and the increase in aerodynamic loss lay within the limits of the design goal. The improved cooling configuration was tested experimentally in a large scale, low speed linear cascade. An analysis of the results shows that the redesign of the cooling configuration has been successful in achieving an improved coolant coverage with lower aerodynamic losses, whilst using the same amount of coolant as in the datum cooling configuration. The improved cooling configuration has reconfirmed conclusions from Friedrichs et al. (1996, 1997); firstly, coolant ejection downstream of the three-dimensional separation lines on the endwall does not change the secondary flow structures; secondly, placement of holes in regions of high static pressure helps reduce the aerodynamic penalties of platform coolant ejection; finally, taking account of secondary flow can improve the design of endwall film-cooling configurations.

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An Experimental Study of Heat Transfer and Film Cooling on Low Aspect Ratio Turbine Nozzles

Cited by 37 publications

References 10 publications

Aerodynamic Aspects of Endwall Film-Cooling

Aerodynamic Aspects of Endwall Film-Cooling

Gas Turbine Film Cooling

The Design of an Improved Endwall Film-Cooling Configuration

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