Publications
243 results found
Costall A, Martinez-Botas RF, 2007, Fundamental characterization of turbocharger turbine unsteady flow behavior, 52nd ASME Turbo Expo 2007, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1827-1839
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- Citations: 9
Wilkins S, Tse L, Martinez-Botas R, 2007, Investigation of SOFC-GT Systems for Hybridised Heavy Duty Transport Applications, ASME EFC2007
Rajoo S, Martinez-Botas RF, 2007, Unsteady effect in a nozzled turbocharger turbine, 52nd ASME Turbo Expo 2007, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1159-1170
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- Citations: 9
Tse L, Wilkins S, Martinez-Botas R, 2006, Power Generation: Integrating of a Solid Oxide Fuel Cell in a Gas Turbine Cycle, Annual Cambridge Energy Symposium - Distributed Energy in the UK
R F Martinez-Botas, A Pesiridis, S Rajoo, et al., 2006, Flow Control Device for a Turbocharger, WO2006/061588
Pesiridis A, Martinez-Botas R, 2006, Active control turbocharger for automotive application: An experimental evaluation, Pages: 223-232
The current paper presents the results from a comprehensive set of experimental tests on a prototype active control turbocharger. This is a continuing series of test work as part of the development of this new type of turbocharger. Driven by the need to comply to increasingly strict emissions regulations as well as a continuing strive for better overall performance the active control turbocharger is intended to provide an improvement over the current state-of-the-art in turbocharging. In this system, the nozzle is able to alter the throat inlet area of the turbine according to the pressure variation of each engine exhaust gas pulse thus imposing a substantially more 'active' form of control of the conditions at the turbine rotor inlet.
Rajoo S, Martinez-Botas R, 2006, Experimental study on the performance of a variable geometry mixed flow turbine for automotive turbocharger, Pages: 183-192
This paper investigates a variable geometry (VG) mixed-flow turbine with a novel, purposely designed pivoting nozzle vane ring. The nozzle vane ring was matched to the 3-dimensional aspect of the mixed-flow rotor leading edge. The VG mixed-flow turbine has been evaluated experimentally, in steady and unsteady conditions. The VG turbine shows higher efficiency and swallowing capacity at various vane angle settings compared to an equivalent nozzleless turbine. But the VG turbine unsteady performance was found to deviate substantially from the quasi-steady assumption, compared to a nozzleless turbine. The VG stator with the new unique vane design is expected to further enhance the mixed-flow turbine benefits in term of engine-turbocharger matching and transient performance.
Karamanis N, Palfreyman D, Arcoumanis C, et al., 2006, Steady and unsteady velocity measurements in a small turbocharger turbine with computational validation, 2nd International Conference on Optical and Laser Diagnostics, Publisher: IOP PUBLISHING LTD, Pages: 173-173, ISSN: 1742-6588
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- Citations: 5
Costall A, Szymko S, Martinez-Botas RF, et al., 2006, Assessment of unsteady behavior in turbocharger turbines, 51st ASME Turbo Expo, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1023-1038
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- Citations: 15
Yuen CHN, Martinez-Botas RF, 2005, Film cooling characteristics of rows of round holes at various streamwise angles in a crossflow: Part II. Heat transfer coefficients, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, Vol: 48, Pages: 5017-5035, ISSN: 0017-9310
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- Citations: 43
Yuen CHN, Martinez-Botas RF, 2005, Film cooling characteristics of rows of round holes at various streamwise angles in a crossflow: Part I. Effectiveness, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, Vol: 48, Pages: 4995-5016, ISSN: 0017-9310
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- Citations: 76
Sudaprasert K, Travis RP, Martinez-Botas RF, 2005, A computational fluid dynamics model of a solid oxide fuel cell, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART A-JOURNAL OF POWER AND ENERGY, Vol: 219, Pages: 159-167, ISSN: 0957-6509
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- Citations: 6
Kanokjaruvijit K, Martinez-Botas RF, 2005, Parametric effects on heat transfer of impingement on dimpled surface, 49th International Gas Turbine and Aeroengine Congress and Exhibition, Publisher: ASME, Pages: 287-296, ISSN: 0889-504X
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- Citations: 37
Kanokjaruvijit K, Martinez-Botas RF, 2005, Jet impingement on a dimpled surface with different crossflow schemes, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, Vol: 48, Pages: 161-170, ISSN: 0017-9310
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- Citations: 99
Palfreyman D, Martinez-Botas RF, 2005, The pulsating flow field in a mixed flow turbocharger turbine: An experimental and computational study, International Gas Turbine and Aeroengine Congress and Exhibition, Publisher: ASME-AMER SOC MECHANICAL ENG, Pages: 144-155, ISSN: 0889-504X
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- Citations: 70
Costall A, Martinez-Botas RF, Palfreyman D, 2005, Detailed study of pulsating flow performance in a mixed flow turbocharger turbine, 50th ASME Turbo-Expo, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1415-1433
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- Citations: 4
Yoon JH, Martinez-Botas RF, 2005, Film cooling performance in a simulated blade tip geometry, 50th ASME Turbo-Expo 2005, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 739-754
Pesiridis A, Martinez-Botas RF, 2005, Experimental evaluation of active flow control mixed-flow turbine for automotive turbocharger application, 50th ASME Turbo-Expo 2005, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 881-895
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- Citations: 3
Szymko S, Martinez-Botas RF, Pullen KR, 2005, Experimental evalation of turbocharger turbine performance under pulsating flow conditions, 50th ASME Turbo-Expo, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1447-1457
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- Citations: 33
Kanokjaruvijit K, Martinez-Botas RF, 2005, Heat transfer and pressure investigation of dimple impingement, 50th ASME Turbo-Expo, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 717-728
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- Citations: 3
Clayton RP, Martinez-Botas RF, 2004, Application of generic algorithms in aerodynamic optimisation design procedures, AERONAUTICAL JOURNAL, Vol: 108, Pages: 611-620, ISSN: 0001-9240
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- Citations: 2
Kanokjaruvijit K, Martinez-Botas RF, 2004, An experimental investigation of the heat transfer due to multiple jets impinging normally on a dimpled surface, 8th UK National Heat Transfer Conference, Publisher: SAGE PUBLICATIONS LTD, Pages: 1337-1347, ISSN: 0954-4062
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- Citations: 6
Palfreyman D, Martinez-Botas RF, 2004, The pulsating flow field in a mixed flow turbocharger turbine: AN experimental and computational study, Pages: 697-708
The turbine stage of an automotive pulse system turbocharger is subjected to an unsteady pulsating flow field due to the rapid opening and closing of the reciprocating engine exhaust valves. This leads to a complex and highly disturbed flow field within the delivery volute and turbine passages, which results in an unusual 'hysteresis' type performance characteristic. The aim of this paper is to investigate the flow field within the turbine stage under these representative conditions, using a computational method validated against experimental data. This paper is separated into two sections. The first deals with the validation of the numerical code and modeling approach. A mesh dependency study is undertaken with cell discretization ranging 200,000, 850, 000 and 1,750,000 cells, where the accuracy is assessed through comparison with experimental performance and flow field measurements. The second part presents an investigation of the flow field under pulse conditions. Time accurate spectra of turbine performance and flow properties at various locations in the turbine stage are presented, as well as contour plots of velocity within a turbine passage at two critical positions during the pulse period.
Kanokjaruvijit K, Martinez-Botas RF, 2004, Parametric effects on heat transfer of impingement on dimpled surface, Pages: 77-88
Jet impingement on a dimpled surface is investigated experimentally for Reynolds numbers in the range 5000-11500, and jet-to-plate spacing from 2 to 12 jet-diameters. These include spatially resolved local Nusselt numbers with impingement both on the dimpled itself and on the flat portion between dimples. Two dimple geometries are considered: hemispherical dimples and double or cusp elliptical dimples. All experiments were carried under maximum crossflow, that is the spent air exits along one way. At the narrow jet-to-plate spacing, such as H/Dj = 2, a vigorous recirculation occurred, which prevented the dimpled plate to enhance heat transfer. The effect of impinging jet positions meant that impinging onto dimples generated more and higher energetic vortices, and this led to better heat transfer performance. Cusped elliptical dimples increase the heat transfer compared to a flat plate less than the hemispherical geometry. The influence of dimple depth was also considered, the shallower dimple, d/Dd = 0.15, improves significantly the heat transfer by 64% compared to that of the flat surface impingement at H/Dj = 4, this result was 38% higher than that for a deeper dimple of d/Dd = 0.25. The very significant increase in average heat transfer makes dimple surface impingement a candidate for cooling applications. Detailed pressure measurements will form a second part of this paper, however, plenum pressure measurements are illustrated here as well as a surface pressure measurement on both streamwise and spanwise directions.
Palfreyman D, Martinez-Botas R, 2004, The pulsating flow field in a mixed flow turbocharger turbine: An experimental and computational study (Paper no. GT2004-53143), N/A, Proceedings of Turbo Expo 2004: ASME Turbo Expo 2004 power for land, sea, and air, Vienna, Austria, 14 - 17 June 2004, Publisher: ASME, Pages: 1-12
Kanokjaruvijit K, Martinez-Botas RF, 2004, Parametric effects on heat transfer of impingement on dimple surface (Paper no. GT2004-53142), N/A, Proceedings of Turbo Expo 2004: ASME Turbo Expo 2004 power for land, sea, and air, Vienna, Austria, 14 - 17 June 2004, Publisher: ASME, Pages: 1-12
Yuen CHN, Martinez-Botas RF, 2003, Film cooling characteristics of a single round hole at various streamwise angles in a crossflow - Part II: heat transfer coefficients, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, Vol: 46, Pages: 237-249, ISSN: 0017-9310
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- Citations: 48
Yuen CHN, Martinez-Botas RF, 2003, Film cooling characteristics of a single round hole at various streamwise angles in a crossflow: Part I effectiveness, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, Vol: 46, Pages: 221-235, ISSN: 0017-9310
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- Citations: 105
Yoon JH, Martinez-Botas R, 2003, Influence of high freestream turbulence on film cooling effectiveness and heat transfer coefficient for an imposed pressure gradient, National heat transfer conference, Oxford, UK, September 2003
Sudaprasert K, Travis RP, Martinez-Botas RF, 2003, A computational fluid dynamics model of a SOFC, Solid oxide fuel cells, Publisher: Electrochemical Society, Pages: 1395-1402
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