Gas side heat transfer

Improvements in methods for predicting heat transfer rates on the hot gas side of turbine airfoils are necessary for improved turbine durability and performance. The development and verification of improved analytical models requires a systematic, closely coupled experimental and analytical program

Turbine Vane External Heat Transfer. Volume 1: Analytical and Experimental Evaluation of Surface Heat Transfer Distributions with Leading Edge Showerhead Film Cooling

Progress in predictive design capabilities for external heat transfer to turbine vanes was summarized. A two dimensional linear cascade (previously used to obtain vane surface heat transfer distributions on nonfilm cooled airfoils) was used to examine the effect of leading edge shower head film cooling on downstream heat transfer. The data were used to develop and evaluate analytical models. Modifications to the two dimensional boundary layer model are described. The results were used to formulate and test an effective viscosity model capable of predicting heat transfer phenomena downstream of the leading edge film cooling array on both the suction and pressure surfaces, with and without mass injection

Turbine airfoil film cooling

The experimental data obtained in this program gives insight into the physical phenomena that occur on a film cooled airfoil, and should provide a relevant data base for verification of new design tools. Results indicate that the downstream film cooling process is a complex function of the thermal dilution and turbulence augmentation parameters with trends actually reversing as blowing strength and coolant-to-gas temperature ratio varied. The pressure surface of the airfoil is shown to exhibit a considerably higher degree of sensitivity to changes in the film cooling parameters and, consequently, should prove to be more of a challenge than the suction surface in accurately predicting heat transfer levels with downsteam film cooling

The effects of leading edge and downstream film cooling on turbine vane heat transfer

The progress under contract NAS3-24619 toward the goal of establishing a relevant data base for use in improving the predictive design capabilities for external heat transfer to turbine vanes, including the effect of downstream film cooling with and without leading edge showerhead film cooling. Experimental measurements were made in a two-dimensional cascade previously used to obtain vane surface heat transfer distributions on nonfilm cooled airfoils under contract NAS3-22761 and leading edge showerhead film cooled airfoils under contract NAS3-23695. The principal independent parameters (Mach number, Reynolds number, turbulence, wall-to-gas temperature ratio, coolant-to-gas temperature ratio, and coolant-to-gas pressure ratio) were maintained over ranges consistent with actual engine conditions and the test matrix was structured to provide an assessment of the independent influence of parameters of interest, namely, exit Mach number, exit Reynolds number, coolant-to-gas temperature ratio, and coolant-to-gas pressure ratio. Data provide a data base for downstream film cooled turbine vanes and extends the data bases generated in the two previous studies. The vane external heat transfer obtained indicate that considerable cooling benefits can be achieved by utilizing downstream film cooling. The data obtained and presented illustrate the interaction of the variables and should provide the airfoil designer and computational analyst the information required to improve heat transfer design capabilities for film cooled turbine airfoils

Analytical and Experimental Evaluation of the Heat Transfer Distribution over the Surfaces of Turbine Vanes

Three airfoil data sets were selected for use in evaluating currently available analytical models for predicting airfoil surface heat transfer distributions in a 2-D flow field. Two additional airfoils, representative of highly loaded, low solidity airfoils currently being designed, were selected for cascade testing at simulated engine conditions. Some 2-D analytical methods were examined and a version of the STAN5 boundary layer code was chosen for modification. The final form of the method utilized a time dependent, transonic inviscid cascade code coupled to a modified version of the STAN5 boundary layer code featuring zero order turbulence modeling. The boundary layer code is structured to accommodate a full spectrum of empirical correlations addressing the coupled influences of pressure gradient, airfoil curvature, and free-stream turbulence on airfoil surface heat transfer distribution and boundary layer transitional behavior. Comparison of pedictions made with the model to the data base indicates a significant improvement in predictive capability

How a turn to critical race theory can contribute to our understanding of 'race', racism and anti-racism in sport

As long as racism has been associated with sport there have been consistent, if not coordinated or coherent, struggles to confront its various forms. Critical race theory (CRT) is a framework established to challenge these racialized inequalities and racism in society and has some utility for anti-racism in sport. CRT's focus on social justice and transformation are two areas of convergence between critical race theorists and anti-racists. Of the many nuanced and pernicious forms of racism, one of the most obvious and commonly reported forms of racism in sport, racial abuse, has been described as a kind of dehumanizing process by Gardiner (2003), as those who are its target are simultaneously (re)constructed and objectified according to everyday myth and fantasy. However, this is one of the many forms of everyday racist experiences. Various forms of racism can be experienced in boardrooms, on television, in print, in the stands, on the sidelines and on the pitch. Many times racism is trivialized and put down as part of the game (Long et al., 2000), yet its impact is rarely the source of further exploration. This article will explore the conceptualization of 'race' and racism for a more effective anti-racism. Critical race theory will also be used to explore the ideas that underpin considerations of the severity of racist behaviour and the implications for anti-racism. © The Author(s) 2010

Talk the talk, walk the walk: Defining Critical Race Theory in research

Over the last decade there has been a noticeable growth in published works citing Critical Race Theory (CRT). This has led to a growth in interest in the UK of practical research projects utilising CRT as their framework. It is clear that research on 'race' is an emerging topic of study. What is less visible is a debate on how CRT is positioned in relation to methodic practice, substantive theory and epistemological underpinnings. The efficacy of categories of data gathering tools, both traditional and non-traditional is a discussion point here to explore the complexities underpinning decisions to advocate a CRT framework. Notwithstanding intersectional issues, a CRT methodology is recognisable by how philosophical, political and ethical questions are established and maintained in relation to racialised problematics. This paper examines these tensions in establishing CRT methodologies and explores some of the essential criteria for researchers to consider in utilising a CRT framework. © 2012 Copyright Taylor and Francis Group, LLC

Reviewing research evidence and the case of participation in sport and physical recreation by black and minority ethnic communities

The paper addresses the implications of using the process of systematic review in the many areas of leisure where there is a dearth of material that would be admitted into conventional Cochrane Reviews. This raises important questions about what constitutes legitimate knowledge, questions that are of critical import not just to leisure scholars, but to the formulation of policy. The search for certainty in an area that lacks conceptual consensus results in an epistemological imperialism that takes a geocentric form. While clearly, there is a need for good research design whatever the style of research, we contend that the wholesale rejection of insightful research is profligate and foolhardy. A mechanism has to be found to capitalise on good quality research of whatever form. In that search, we draw upon our experience of conducting a review of the material available on participation in sport and physical recreation by people from Black and minority ethnic groups. The paper concludes with a proposal for a more productive review process that makes better use of the full panoply of good quality research available. © 2012 © 2012 Taylor & Francis

‘Race’ Talk! Tensions and Contradictions in Sport and PE

Background: The universal sport discourses of inclusion, belonging, meritocracy, agency, and equality are so widespread that few challenge them. It is clear from the most cursory interest in sport, PE and society that the lived reality is quite different and ambiguous. Racial disparities in the leadership and administration of sport are commonplace world wide; yet from research into ‘race’ in sport and PE the public awareness of these issues is widespread, where many know that racism takes place it is always elsewhere For many this racism is part of the game and something that enables an advantage to be stolen, for others it is trivial and not worthy of deeper thought. This paper explores the contradictions and tensions of the author’s experience of how sport and PE students talk about ‘race’. ‘Race’ talk is considered here in the context of passive everyday ‘race’ talk, dominant discourses in sporting cultures, and colour-blindness. This paper focuses on the pernicious yet persistent nature of ‘race’ talk while demystifying its multifarious, spurious, and more persuasive daily iterations. Theoretical framework: Drawing on Guinier and Torres’ (2003) ideas of resistance through political race consciousness and Bonilla-Silva’s (2010) notion of colour-blindness the semantics of ‘race’ and racialisation in sport and PE are interrogated through the prism of Critical Race Theory (CRT). Critical race scholarship has been used in sport and PE to articulate a political application of ‘race’ as a starting point for critical activism, to disrupt whiteness, and to explore the implications of ‘race’ and racism. CRT is used here to centre ‘race’ and racialised relations where disciplines have consciously or otherwise excluded them. Importantly, the centreing of ‘race’ by critical race scholars has advanced a strategic and pragmatic engagement with this slippery concept that recognises its paradoxical but symbolic location in social relations. Discussion: Before exploring ‘race’ talk in the classroom, using images from the sport media as a pedagogical tool, the paper considers how effortlessly ‘race’ is recreated and renewed. The paper then turns to explore how the effortless turn to everyday ‘race’ talk in the classroom can be viewed as an opportunity to disrupt common racialised assumptions with the potential to implicate those that passively engage in it. Further the diagnostic, aspirational and activist goals of political race consciousness are established as vehicles for a positive sociological experience in the classroom. Conclusion: The work concludes with a pragmatic consideration of the uses and dangers of passive everyday ‘race’ talk and the value of a political race consciousness in sport and PE. Part of the explanation for the perpetuation of ‘race’ talk and the relative lack of concern with its impact in education and wider society is focused on how the sovereignty of sport and PE trumps wider social concerns of ‘race’ and racism because of at least four factors 1) the liberal left discourses of sporting utopianism 2) the ‘race’ logic that pervades sport, based upon the perceived equal access and fairness of sport as it coalesces with the, 3) 'incontrovertible facts' of black and white superiority [and inferiority] in certain sports, ergo the racial justifications for patterns of activity in sport and PE 4) the racist logic of the Right perpetuated through a biological reductionism in sport and PE discourses. Keywords: ‘Race’ Talk; Critical Race Theory; Political Race Consciousnes