Publications
243 results found
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
Cunnel C, Pangalis MG, Martinez-Botas RF, 2002, Integration of solid oxide fuel cells into gas turbine power generation cycles. Part 2: hybrid model for various integration schemes, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART A-JOURNAL OF POWER AND ENERGY, Vol: 216, Pages: 145-154, ISSN: 0957-6509
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- Citations: 27
Martinez-Botas RF, 2002, Unsteady effects, electric assisted systems an dfuture trends in turbocharger engines, THIESEL 2002 conference on thermo-and fluid dynamic-processes in diesel engines, Valencia, Spain, 11 - 13 September 2002, Publisher: N/A
Yoon JH, Martinez-Botas RF, 2002, Effect of inlet geometry on the turbine blade tip region heat transfer coefficient and effectiveness (IMECE2002-39607), Proceedings of the ASME international mechanical engineering congress and: exposition, New Orleans,Louisiana, 17 - 22 November 2002, Publisher: ASME, Pages: 273-282
Palfreyman DD, Martinez-Botas RF, Karamanis N, 2002, Computational and experimental investigation of the aerodynamics of turbocharger mixed-flow turbines, London, 7th international conference on turbochargers and turbocharging, London, UK, 14 May 2002, Publisher: Mechanical Engineering Publications, Pages: 45-60
Palfreyman D, Martinez-Botas RF, 2002, Numerical study of the internal flow field characteristics in mixed flow turbines (GT-2002-30372), ASME turbo expo 2002, Amsterdam, The Netherlands, June 2002, Publisher: ASME, Pages: 455-472
Martinez-Botas RF, 2002, Mixed-flow turbine: Steady and unsteady performance with detailed flow measurements, Conference on Thermofluidynamic Processes in Diesel Engines (THIESEL 2000), Publisher: SPRINGER-VERLAG BERLIN, Pages: 211-235
Szymko S, Martinez-Botas R, Pullen KR, et al., 2002, A high-speed, permanent magnet eddy-current dynamometer for turbocharger research, London, Turbochargers and turbocharging VII: 7th international conference, May 2002, Publisher: Mechanical Engineering Publications, Pages: 213-224
Pangalis MG, Martinez-Botas RF, Brandon NP, 2002, Integration of solid oxide fuel cells into gas turbine power generation cycles. Part 1: fuel cell thermodynamic modelling, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART A-JOURNAL OF POWER AND ENERGY, Vol: 216, Pages: 129-144, ISSN: 0957-6509
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- Citations: 33
Karamanis N, Martinez-Botas RF, 2002, Mixed-flow turbines for automotive turbochargers: steady and unsteady performance, International Journal of Engine Research, Vol: 3, Pages: 127-138, ISSN: 1468-0874
Szymko S, Martinez-Botas R, Pullen KR, et al., 2002, A high-speed, permanent magnet eddy-current dynamometer for turbocharger research, London, Turbochargers and turbocharging VII: 7th international conference, May 2002, Publisher: Mechanical Engineering Publications, Pages: 213-224
Yuen CHN, Martinez-Botas RE, Whitelaw JH, 2001, Film cooling effectiveness downstream of compound and fan-shaped holes, Proceedings of the ASME Turbo Expo, Vol: 3
The steady-state wide band liquid crystal technique is used to study the film cooling performance downstream of a variety of geometries in a fiat plate. This technique provides a detailed measurement of both cooling effectiveness and heat transfer coefficient. This paper presents the effects of compound and fan-shaped holes, the effect of streamwise angle variation has been presented at previous meetings. The following configurations are investigated: a single hole, a row of holes with a pitch-to-diameter ratio, p/D, of 3, two inline rows with p/D of 3 and two staggered rows with p/D of 6; all with a stream-wise angle of 30°. The spacing between two rows was chosen as 12.4D. Two lateral injection are investigated: 30° and 60° compound angle. The fan shaped hole used comprised of a lateral expansion of 14° from the original simple cylindrical shape with streamwise inclination of 30°; forward expansion was not incorporated. The length-to-diameter ratio, L/D, was maintained at a value of 4 for all the compound cases, the L/D for the fan shaped-hole was 6, larger due to its physical limitation. The tests were performed with a jet-tofreestream density ratio of 1.5; achieved by using a foreign gas (CO2) injection. The range of momentum flux ratios (M) covered was 0.33 to 1.67. The row of 30° compound angle holes gave a lower value of effectiveness when compared to the non-compound case at M<0.67, but greater values and coverage at M>I.0, consistent with previous experiments. The row of 60° compound angle gave greater effectiveness, coverage and uniformity than the row of 30° compound at a given blowing ratio; the jet-to-jet interaction was greater for the 60° row due to the added lateral momentum. The row of 60° compound gave an increase of order 100% relative to the non-compounded row for M>I. Two inliue rows of fan-shape holes delivered less effectiveness than the corresponding single row at the same spanwise distance for
Martinez-Botas R, 2001, Mixed-flow turbines: steady and unsteady performance with detailed flow measurements, Thermofluid dynamic processes in diesel engines, Editors: Whitelaw, Payri, Desantes, Publisher: Springer Verlag, Pages: 239-263
Pullen KR, Martinez-Botas R, Buffard K, 2001, Design problems in micro-turbine generators, Micro turbine generators, Editors: Moore, Moore, Bury St Edmonds, Publisher: Professional Engineering Publishing, Pages: 85-96, ISBN: 9781860583919
Panting J, Pullen KR, Martinez-Botas RF, 2001, Turbocharger motor-generator for improvement of transient performance in an internal combustion engine, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART D-JOURNAL OF AUTOMOBILE ENGINEERING, Vol: 215, Pages: 369-383, ISSN: 0954-4070
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- Citations: 25
Karamanis N, Martinez-Botas RF, Su CC, 2000, Mixed flow turbines: inlet an exit flow under steady and pulsating conditions, International Gas Turbine and Aeroengine Congress and Exhibition (Munich Germany) Series GT no. 470, Pages: 1-9
Martinez-Botas RF, Yuen CHN, 2000, Measurement of local heat transfer coefficient and film cooling effectiveness through discrete holes, International gas turbine & Aeroengine Congress and Exhibition Munich germany ASME paper 2000-GT-243
Karamanis N, Martinez-Botas RF, Su CC, 1999, Detailed flow measurements at the exit of a mixed flow turbine under steady flow conditions, International Gas Turbine and Aeroengine Congress and Exhibition (Indianapolis USA), Publisher: ASME-GT-342, Pages: 1-9
Arcoumanis C, Karamanis N, Martinez-Botas RF, et al., 1999, Unsteady characteristics of a mixed-flow turbocharger turbine, 3rd European Conference on Turbomachinery-(London), Pages: 905-922
Arcoumanis C, Martinez-Botas RF, Nouri JM, et al., 1998, Inlet and exit flow characteristics of mixed flow turbines
The steady performance of mainly two high pressure ratio mixed flow turbines for an automotive turbocharger (expansion ratio of 2.9) has been investigated and the results indicated superior performance of the rotor with a constant inlet blade angle relative to that with a nominally constant incidence angle. These results have been confirmed by the measurement of the three components of velocity, the Reynolds normal stresses and the flow angle at the inlet and exit of the mixed-flow turbine rotors by laser Doppler velocimetry (LDV) under steady state conditions. The turbine testing conditions corresponded to the 50% and 70% design speeds, equivalent to 29,400 and 41,300 rpm respectively. The velocity results have indicated that the flow upstream of the rotor varies significantly along the blade inlet plane, and this is more evident at the 50% design speed. The flow in the volute behaves as a free vortex except in regions close to the hub, while the exit flow revealed that the constant incidence design rotor has a significantly higher exit swirl angle than the constant blade design, in agreement with the higher exit kinetic energy loss in the former case.
Arcoumanis C, Martinez-Botas RF, Su CC, 1998, Measured and predicted flow characteristics of mixed flow turbocharger turbines, IMechE 6th International Conference on Turbocharging and Air Management Systems, Pages: 157-170
Arcoumanis C, Martinez-Botas RF, Nouri JM, et al., 1998, Inlet and exit flow characteristics of mixed flow turbines, American Society of Mechanical Engineers
Arcoumanis C, Martinez-Botas RF, Nouri JM, et al., 1997, Performance and exit flow characteristics of mixed-flow turbines, International Journal of Rotating Machinery, Vol: 3, Pages: 277-293, ISSN: 1023-621X
Martinez-Botas RF, Pullen KR, Shi F, 1996, Numerical calculations of a turbine volute using a 3-D Navier-Stokes solver, ASME Paper 96-GT-66, Publisher: American Society of Mechanical Engineers, Pages: 1-9, ISSN: 0402-1215
Martinez-Botas RF, Pullen KR, Shi F, 1996, Numerical calculations of a turbine volute using a 3-D Navier-Stokes solver, ASME Paper 96-GT-66, Publisher: American Society of Mechanical Engineers, Pages: 1-9, ISSN: 0402-1215
Chen H, Hakeem I, Martinez-Botas RF, 1996, Modelling of a turbocharger turbine under pulsating inlet conditions, Proceedings of the Institution of Mechanical Engineers Part A-Journal of Power and Energy, Vol: 210, Pages: 397-408, ISSN: 0957-6509
Arcoumanis C, Hakeem I, Khezzar L, et al., 1995, Performance of a mixed flow turbocharger turbine under pulsating flow conditions
The performance of a high pressure ratio (P.R.=2.9) mixed flow turbine for an automotive turbocharger has been investigated and the results revealed its better performance relative to a radial-inflow geometry under both steady and pulsating flow conditions. The advantages offered by the constant blade angle rotor allow better turbocharger-engine matching and maximization of the energy extracted from the pulsating engine exhaust gases. In particular, the mixed inlet blade geometry resulted in high efficiency at high expansion ratios where the engine-exhaust pulse energy is maximum. The efficiency characteristics of the mixed flow turbine under steady conditions were found to be fairly uniform when plotted against the velocity ratio, with a peak efficiency at the design speed of 0.75. The unsteady performance as indicated by the mass-averaged total-to-static efficiency and the swallowing capacity exhibited a departure from the quasi-steady assumption which is analysed and discussed.
Arcoumanis C, Hakeem I, Khezzar L, et al., 1995, Performance of a mixed flow turbocharger turbine under pulsating flow conditions, ISSN: 0402-1215
The performance of a high pressure ratio (P.R.=2.9) mixed flow turbine for an automotive turbocharger has been investigated and the results revealed its better performance relative to a radial-inflow geometry under both steady and pulsating flow conditions. The advantages offered by the constant blade angle rotor allow better turbocharger-engine matching and maximization of the energy extracted from the pulsating engine exhaust gases. In particular, the mixed inlet blade geometry resulted in high efficiency at high expansion ratios where the engine-exhaust pulse energy is maximum. The efficiency characteristics of the mixed flow turbine under steady conditions were found to be fairly uniform when plotted against the velocity ratio, with a peak efficiency at the design speed of 0.75. The unsteady performance as indicated by the mass-averaged total-to-static efficiency and the swallowing capacity exhibited a departure from the quasi-steady assumption which is analysed and discussed.
Martinez-Botas RF, Lock GD, Jones TV, 1995, Heat transfer measurements in an annular cascade of transonic gas turbine blades using the transient liquid crystal technique, Journal of Turbomachinery, Vol: 117, Pages: 425-431, ISSN: 0889-504X
Heat transfer measurements have been made in the Oxford University Cold Heat Transfer Tunnel employing the transient liquid crystal technique. Complete contours of the heat transfer coefficient have been obtained on the aerofoil surfaces of a large annular cascade of high-pressure nozzle guide vanes (mean blade diameter of 1.11 m and axial chord of 0.0664 m). The measurements are made at engine representative Mach and Reynolds numbers (exit Mach number 0.96 and Reynolds number 2.0 × 106). A novel mechanism is used to isolate five preheated blades in the annulus before an unheated flow of air passes over the vanes, creating a step change in heat transfer. The surfaces of interest are coated with narrow-band thermochromic liquid crystals and the color crystal change is recorded during the run with a miniature CCD video camera. The heat transfer coefficient is obtained by solving the onedimensional heat transfer equation for all the points of interest. This paper will describe the experimental technique and present results of heat transfer and flow visualization. © 1995 ASME.
Martinez-Botas RF, Lock GD, Jones TV, 1994, Heat transfer measurements in an annular cascade of transonic gas turbine blades using the transient liquid crystal technique
Heat transfer measurements have been made in the Oxford University Cold Heat Transfer Tunnel employing the transient liquid crystal technique. Complete contours of the heat transfer coefficient have been obtained on the aerofoil surfaces of a large annular cascade of high pressure nozzle guide vanes (mean blade diameter of 1.11 m and axial chord of 0.0664 m). The measurements are made at engine representative Mach and Reynolds numbers (exit Mach number 0.96 and Reynolds number 2.0 × 106 ). A novel mechanism is used to isolate five preheated blades in the annulus before an unheated flow of air passes over the vanes, creating a step change in heat transfer. The surfaces of interest are coated with narrow-band thermochromic liquid crystals and the colour crystal change is recorded during the run with a miniature CCD video camera. The heat transfer coefficient is obtained by solving the one dimensional heat transfer equation for all the points of interest. This paper will describe the experimental technique and present results of heat transfer and flow visualisation.
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