A Three-Dimensional Coupled Internal/External Simulation of a Film-Cooled Turbine Vane PDF Download

Author: James D. Heidmann
Publisher:
ISBN:
Category :
Languages : en
Pages : 24

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Author: James D. Heidmann
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Presented at the International Gas Turbine & Aeroengine Congress & Exhibition, Indianapolis, Indiana, June 7-10, 1999.

Author: B. Sundén
Publisher: WIT Press
ISBN: 1853129569
Category : Science
Languages : en
Pages : 361

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Providing invaluable information for both graduate researchers and R & D engineers in industry and consultancy, this book focuses on the modelling and simulation of fluid flow and thermal transport phenomena in turbulent convective flows. Its overall objective is to present state-of-the-art knowledge in order to predict turbulent heat transfer processes in fundamental and idealized flows as well as in engineering applications. The chapters, which are invited contributions from some of the most prominent scientists in this field, cover a wide range of topics and follow a unified outline and presentation to aid accessibility.

Author: X. Coudray
Publisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 0

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The increased severity of the thermal environment of high pressure turbine blades and vanes requires accurate calculations for the successful design of these parts. In this paper, the prediction of the temperature field in the near-cooling-hole region on a film cooled turbine vane is presented. The surface distribution of the heat transfer coefficient and the film cooling effectiveness on the vane in presence of one or several film cooling injections is obtained from boundary layer calculations and via experimental correlations. Cooling jet coalescence is taken into account as well as the main parameters governing this physical phenomenon. The internal boundary conditions result from available correlations. The study was conducted on two different configurations : a flat plate including an injection through two rows of holes and a turbine vane including three injections through two rows of holes on the suction side. Thermal computations using a three-dimensional finite element code yield strong temperature distortions and high temperature gradients around the injection zones. The study also indicates that the three-dimensional temperature field just downstream of the injections becomes two-dimensional when jet coalescence takes place. The influence of one or several obstructed injection holes on the temperature field is studied; important effects are observed when the main flow temperature is high.

Author: Jatin Gupta
Publisher:
ISBN:
Category : Heat
Languages : en
Pages : 55

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Abstract: The conventional thermal design method of cooled turbine blade consists of independent decoupled analysis of the blade external flow, the blade internal flow and the analysis of heat conduction in the blade itself. To make such a calculation, proper interface conditions need to be applied. In the absence of film cooling, a proper treatment would require computation of heat transfer coefficient by computing heat flux for an assumed wall temperature. This yields an invariant h to the wall and free stream temperature that is consistent with the coupled calculation. When film-cooling is involved the decoupled method does not yield a heat transfer coefficient that is invariant and a coupled analysis becomes necessary. Fast computers have made possible this analysis of coupling the conduction to both the internal and external flow. Such a single coupled numerical simulation is known as conjugate heat transfer simulation. The conjugate heat transfer methodology has been employed to predict the flow and thermal properties, including the metal temperature, of a particular NASA turbine vane. The three-dimensional turbine vane is subjected to hot mainstream flow and is cooled with air flowing radially through ten cooling channels. The passage flow and heat transfer, internal coolant flow and heat transfer, and conduction within the metal are solved simultaneously using conjugate heat transfer methodology. Unlike the decoupled approach, the conjugate simulation does not require thermal boundary conditions on the turbine walls. It is believed that turbulence has a large influence on heat transfer and hence in the present study, a modified k-omega model by Wilcox was used for the external flow and it was compared to Wilcox's standard k-omega model to see if the new model provided any improvement in predicting the heat transfer on the blade surface. Results here have shown that, for the present geometry, the standard model is still much better in predicting temperature and hence the heat transfer over the blade surface than the modified model. A thermal barrier coating (TBC) "system" is used to thermally protect turbine engine blades and vanes from the hot gases in gas turbine engines. The overall results from this study, including turbulence modeling and the use of TBC, are encouraging and indicate that conjugate heat transfer simulation with proper turbulence closure is a viable tool in turbine heat transfer analysis and cooling design.

Author:
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 412

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Author:
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 414

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Author: Amy Mensch
Publisher:
ISBN:
Category :
Languages : en
Pages :

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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. Turbine designers often rely on multiple thermal protection techniques, including internal cooling, external film cooling, and thermal barrier coatings to efficiently cool components and limit the use of coolant. Traditionally, the effectiveness of such cooling technologies is quantified by considering the convection and conduction heat transfer mechanisms separately. The current research considers the combined effects of both internal and external cooling in a single experiment or simulation using a conjugate heat transfer approach.The geometry used for this study is a turbine blade endwall, which is influenced by three-dimensional vortices generated by the passage flow. The experiments and computational simulations include impingement and film cooling as well as conduction through the endwall. Appropriate geometric and flow parameters are properly scaled to ensure engine relevant dimensionless temperatures are obtained. The overall effectiveness, which is a scaled wall temperature, is compared for multiple cases, including different cooling configurations and the implementation of endwall contouring, thermal barrier coatings, and contaminant deposition. The measurements showed that impingement cooling was a larger contributor to the combined overall effectiveness compared to film cooling. The area-averaged contoured endwall overall effectiveness was similar to the flat endwall despite local differences in film cooling effectiveness and impingement effectiveness. The thermal barrier coating significantly increased overall effectiveness by reducing the external heat transfer. Contaminant deposition increased surface roughness, which increased external heat transfer to the endwall.Computational simulations of conjugate heat transfer and time-resolved flowfield measurements helped to understand the complex mechanisms acting together to generate the overall cooling effectiveness. The predicted endwall temperature fields show the three-dimensional temperature gradients present in conjugate heat transfer. The flat and contoured endwall flowfield measurements show that film cooling jets and the passage vortex interact to generate the secondary flowfield impacting endwall heat transfer. Several recommendations for mitigating increased heat transfer and optimizing the cooling performance for gas turbine endwalls are given.

Author: Robert William MacCormack
Publisher: World Scientific
ISBN: 9789812810793
Category : Technology & Engineering
Languages : en
Pages : 528

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This series of volumes on the OC Frontiers of Computational Fluid DynamicsOCO was introduced to honor contributors who have made a major impact on the field. The first volume was published in 1994 and was dedicated to Prof Antony Jameson; the second was published in 1998 and was dedicated to Prof Earl Murman. The volume is dedicated to Prof Robert MacCormack. The twenty-six chapters in the current volume have been written by leading researchers from academia, government laboratories, and industry. They present up-to-date descriptions of recent developments in techniques for numerical analysis of fluid flow problems, and applications of these techniques to important problems in industry, as well as the classic paper that introduced the OC MacCormack schemeOCO to the world. Contents: The Effect of Viscosity in Hypervelocity Impact Cratering (R W MacCormack); The MacCormack Method OCo Historical Perspective (C M Hung et al.); Numerical Solutions of Cauchy-Riemann Equations for Two and Three Dimensional Flows (M M Hafez & J Houseman); Extension of Efficient Low Dissipation High Order Schemes for 3-D Curvilinear Moving Grids (M Vinokur & H C Yee); Scalable Parallel Implicit Multigrid Solution of Unsteady Incompressible Flows (R Pankajakshan et al.); Lattice Boltzmann Simulation of Incompressible Flows (N Satofuka & M Ishikura); Numerical Simulation of MHD Effects on Hypersonic Flow of a Weakly Ionized Gas in an Inlet (R K Agarwal & P Deb); Development of 3D DRAGON Grid Method for Complex Geometry (M-S Liou & Y Zheng); Advances in Algorithms for Computing Aerodynamic Flows (D W Zingg et al.); Selected CFD Capabilities at DLR (W Kordulla); CFD Applications to Space Transportation Systems (K Fujii); Information Science OCo A New Frontier of CFD (K Oshima & Y Oshima); Integration of CFD into Aerodynamics Education (E M Murman & A Rizzi); and other papers. Readership: Researchers and graduate students in numerical and computational mathematics."

Author: James Michael Cutbirth
Publisher:
ISBN:
Category : Gas-turbine
Languages : en
Pages : 858

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