Publications
243 results found
Romagnoli A, Martinez-Botas RF, Rajoo S, 2011, Steady state performance evaluation of variable geometry twin-entry turbine, INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW, Vol: 32, Pages: 477-489, ISSN: 0142-727X
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- Citations: 37
Tse LKC, Wilkins S, McGlashan N, et al., 2011, Solid oxide fuel cell/gas turbine trigeneration system for marine applications, Journal of Power Sources, Vol: 196, Pages: 3149-3162
Shipping contributes 4.5% to global CO2 emissions and is not covered by the Kyoto Agreement. One method of reducing CO2 emissions on land is combined cooling heating and power (CCHP) or trigeneration, with typical combined thermal efficiencies of over 80%. Large luxury yachts are seen as an ideal entry point to the off-shore market for this developing technology considering its current high cost.This paper investigates the feasibility of combining a SOFC-GT system and an absorption heat pump (AHP) in a trigeneration system to drive the heating ventilation and air conditioning (HVAC) and electrical base-load systems. A thermodynamic model is used to simulate the system, with various configurations and cooling loads. Measurement of actual yacht performance data forms the basis of this system simulation.It is found that for the optimum configuration using a double effect absorption chiller in Ship 1, the net electric power increases by 47% relative to the electrical power available for a conventional SOFC-GT-HVAC system. This is due to more air cooled to a lower temperature by absorption cooling; hence less electrical cooling by the conventional HVAC unit is required. The overall efficiency is 12.1% for the conventional system, 34.9% for the system with BROAD single effect absorption chiller, 43.2% for the system with double effect absorption chiller. This shows that the overall efficiency of a trigeneration system is far higher when waste heat recovery happens.The desiccant wheel hardly reduces moisture from the outdoor air due to a relative low mass flow rate of fuel cell exhaust available to dehumidify a very large mass flow rate of HVAC air, Hence, desiccant wheel is not recommended for this application.
Romagnoli A, Martinez-Botas RF, 2011, Performance Prediction of A Nozzled & Nozzleless Mixed-Flow Turbine in Steady Conditions, International Journal of Mechanical Sciences, Vol: 53, Pages: 557-574
Carey C, McAllister M, Sandford M, et al., 2011, Extreme engine downsizing, Innovations in Fuel Economy and Sustainable Road Transport Conference, Publisher: WOODHEAD PUBL LTD, Pages: 135-147
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- Citations: 16
Terdich N, Martinez-Botas RF, Howey DA, et al., 2011, Off-Road Diesel Engine Transient Response Improvement by Electrically Assisted Turbocharging, SAE ICE2011 - 10th International Conference on Engines & Vehicles, Publisher: Society of Automotive Engineers
Hey J, Howey DA, Martinez-Botas R, et al., 2010, Transient Thermal Modeling of an Axial Flux Permanent Magnet (AFPM) Machine Using a Hybrid Thermal Model, International Conference on Thermal and Fluids Engineering, Publisher: World Academy of Science, Engineering and Technology (WASET)
This paper presents the development of a hybrid thermal model for the EVO Electric AFM 140 Axial Flux Permanent Magnet (AFPM) machine as used in hybrid and electric vehicles. The adopted approach is based on a hybrid lumped parameter and finite difference method. The proposed method divides each motor component into regular elements which are connected together in a thermal resistance network representing all the physical connections in all three dimensions. The element shape and size are chosen according to the component geometry to ensure consistency. The fluid domain is lumped into one region with averaged heat transfer parameters connecting it to the solid domain. Some model parameters are obtained from Computation Fluid Dynamic (CFD) simulation and empirical data. The hybrid thermal model is described by a set of coupled linear first order differential equations which is discretised and solved iteratively to obtain the temperature profile. The computation involved is low and thus the model is suitable for transient temperature predictions. The maximum error in temperature prediction is 3.4% and the mean error is consistently lower than the mean error due to uncertainty in measurements. The details of the model development, temperature predictions and suggestions for design improvements are presented in this paper.
Romagnoli A, Martinez-Botas RF, Rajoo S, 2010, Turbine performance studies for automotive turbochargers. Part 2: Unsteady analysis, Pages: 387-408
This paper presents the results of an experimental investigation conducted on different turbine designs for an automotive turbocharger. The design progression was based on a commercial nozzleless unit that was modified into a variable geometry single and twin entry turbine. The main geometrical parameters were kept constant for all the configurations and the turbine was tested under steady and pulsating flow conditions. The steady flow results and analysis is presented in the Part I of this paper, Romagnoli et al. [1]. This part of the paper will discuss on the details of the unsteady experimentation, analysis and results. The unsteady curves of the turbines of different designs showed the conventional looping characteristics representing filling and emptying effects. The unsteady testing on the turbines showed a bigger departure of the nozzled turbine from the steady curve than the nozzleless. The turbine performance for "in-phase" and "out-of-phase" mode was also measured and compared to single entry configurations. © Authors 2010.
Romagnoli A, Martinez-Botas RF, Rajoo S, 2010, Turbine performance studies for automotive turbochargers. Part 1: Steady analysis, Pages: 431-457
This paper presents the results from an experimental investigation conducted on different turbine designs for an automotive turbocharger. The design progression was based on a commercial nozzleless unit that was modified into a variable geometry single and twin entry turbine. The main geometrical parameters were kept constant for all the configurations and the turbine was tested under steady and pulsating flow conditions (pulsating findings are presented in an accompanying paper). A significant depreciation in efficiency was measured between the single and twin entry configuration due to the mixing effects. The nozzleless unit provides the best compromise in terms of performance at different speeds. The twin entry turbine was also tested under partial and unequal admissions. Based on the test results, a method to determine the swallowing capacity under partial admission given the full admission map is presented. The test results also showed that the turbine swallowing capacity under unequal admission is linked to the full admission case. © Authors 2010.
Rajoo S, Martinez-Botas RF, 2010, Unsteady Effect in a Nozzled Turbocharger Turbine, JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME, Vol: 132, ISSN: 0889-504X
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- Citations: 32
Kanokjaruvijit K, Martinez-Botas RF, 2010, Heat transfer correlations of perpendicularly impinging jets on a hemispherical-dimpled surface, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, Vol: 53, Pages: 3045-3056, ISSN: 0017-9310
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- Citations: 30
Sudaprasert K, Travis RP, Martinez-Botas RF, 2010, A Study of Temperature Distribution Across a Solid Oxide Fuel Cell Stack, JOURNAL OF FUEL CELL SCIENCE AND TECHNOLOGY, Vol: 7, ISSN: 1550-624X
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- Citations: 13
Romagnoli A, Martinez-Botas R, 2010, NON-ADIABATIC COMPRESSOR EFFICIENCY OF TURBOCHARGER: A STATISTICAL APPROACH, ASME Turbo Expo 2010, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 495-506
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- Citations: 2
Copeland CD, Newton P, Martinez-Botas R, et al., 2010, THE EFFECT OF UNEQUAL ADMISSION ON THE PERFORMANCE AND LOSS GENERATION IN A DOUBLE-ENTRY TUBOCHARGER TURBINE, ASME Turbo Expo 2010, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1733-1745
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- Citations: 6
Bin Mamat AMI, Martinez-Botas RF, 2010, MEAN LINE FLOW MODEL OF STEADY AND PULSATING FLOW OF A MIXED-FLOW TURBINE TURBOCHARGER, ASME Turbo Expo 2010, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 2393-2404
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- Citations: 5
Pesiridis A, Martinez-Botas RF, 2010, Experimental Evaluation of the Active Control Turbocharger Prototype under Simulated Engine Conditions, ASME Turbo Expo 2010, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 507-520
Romagnoli A, Martinez-Botas R, 2009, HEAT TRANSFER ON A TURBOCHARGER UNDER CONSTANT LOAD POINTS, 54th ASME Turbo Expo 2009, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 163-174
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- Citations: 17
Merigot Y, Rajoo S, Martinez-Botas RF, 2009, ACTIVE CONTROL TURBOCHARGER (ACT), A METHOD TO IMPROVE ENERGY EXTRACTION FROM AN ENGINE EXHAUST GAS, 54th ASME Turbo Expo 2009, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 137-151
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- Citations: 1
Costall AW, McDavid RM, Martinez-Botas RF, et al., 2009, PULSE PERFORMANCE MODELING OF A TWIN ENTRY TURBOCHARGER TURBINE UNDER FULL AND UNEQUAL ADMISSION, 54th ASME Turbo Expo 2009, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1255-1266
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- Citations: 2
Copeland CD, Martinez-Botas R, Seiler M, 2009, COMPARISON BETWEEN STEADY AND UNSTEADY DOUBLE -ENTRY TURBINE PERFORMANCE USING THE QUASI-STEADY ASSUMPTION, 54th ASME Turbo Expo 2009, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1203-1212
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- Citations: 4
Rajoo S, Martinez-Botas R, 2008, Mixed flow turbine research: A review, JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME, Vol: 130, ISSN: 0889-504X
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- Citations: 42
Kanokjaruvijit K, Martinez-Botas RF, 2008, Heat transfer and pressure investigation of dimple impingement - art. no. 011003, 50th ASME Turbo-Expo, Pages: 11003-11003
Heat transfer and pressure results of an inline array of round jets impinging on a staggered array of dimples are reported with the consideration of various geometric and parametric effects; results are normalized against flat plate data. The heat transfer was measured by using transient wideband liquid crystal method. The geometrical configurations considered were crossflow (or spent-air exit) scheme, dimple geometries, and impinging positions. Three crossflow schemes were tested such as one-way, two-way, and free exits. These led to the idea of the coupling effects of impingement and channel flow depending on which one dominated. Hemispherical and cusped elliptical dimple shapes with the same wetted area were considered and found that both dimples showed the similarity in heat transfer results. Impinging positions on dimples and on flat portions adjacent to dimples were examined. Throughout the study, the pitch of the nozzle holes was kept constant at four jet diameters. The investigated parameters were Reynolds number (Re-Dj) ranged from 5000 to 11,500, jet-to-plate spacing (H/D-j) varied from 1 to 12 jet diameters, dimple depths (d/D-d) of 0.15, 0.25, and 0.29, and dimple curvature (D-j/D-d) of 0.25, 0.50, and 1.15. The shallow dimples (d/D-d=0,15) improved heat transfer significantly by 70% at H/D-j=2 compared to that of the flat surface, while this value was 30% for the deep ones (d/D-d= 0.25). The improvement also occurred to the moderate and high D-j/D-d. The total pressure was a function of ReDj and H/D-j when H/D-j < 2, but it was independent of the target plate geometry. The levels of the total pressure loss of the dimpled plates werenot different from those of the flat surface under the same setup conditions. Wall static pressure was measured by using static taps located across each plate. Re-Dj and H/D-j affected the level of the static pressure while the dimple depth influenced the stagnation peaks, and the crossflow scheme affected the shape of the
Kanokjaruvijit K, Martinez-Botas RF, 2008, Heat transfer and pressure investigation of dimple impingement, 50th ASME Turbo-Expo 2005, Publisher: ASME, ISSN: 0889-504X
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- Citations: 24
Rajoo S, Martinez-Botas RF, 2008, LEAN AND STRAIGHT NOZZLE VANES IN A VARIABLE GEOMETRY TURBINE: A STEADY AND PULSATING FLOW INVESTIGATION, 53rd ASME Turbo Expo 2008, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1589-1601
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- Citations: 1
Copeland CD, Martinez-Botas R, Seiler M, 2008, UNSTEADY PERFORMANCE OF A DOUBLE ENTRY TURBOCHARGER TURBINE WITH A COMPARISON TO STEADY FLOW CONDITIONS, 53rd ASME Turbo Expo 2008, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1579-1588
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- Citations: 4
Chan RTP, Martinez-Botas RF, Gohar R, 2007, Isoviscous flow past a rigid sphere partially immersed in a thin oil film, Lubrication Science, Vol: 19, Pages: 197-212, ISSN: 0954-0075
Numerical solutions to steady state circular contact elastohydrodynamic lubrication problems normally employ Reynolds equation, forcing the assumption that the flow through the conjunction is two-dimensional and singlephase. In this paper, the full Navier-Stokes equations are used on a simpler rigid isoviscous sliding point contact. The aim of the study was to compute the lubricant flow patterns through and around the conjunction of a point contact when the oil inlet is a free surface that has a similar wavy shape to the wake. This model is like some seen experimentally in a ball and plate machine or industrially in a radial ball bearing with insufficient lubricant supply. There is first a discussion on the alteration with time of the oil wake geometry after it has left the conjunction. Then, the computed results mapped the areas of varying concentration between oil and air. They showed an accumulation of oil and vapour forming a reservoir at the inlet to the conjunction. Within it was a vortex attached to the stationary surface, just downstream of which, the main pressure distribution commences. The computed flow patterns were compared with experimental pictures wherever possible. Copyright © 2007 John Wiley & Sons, Ltd.
Tse L, Wilkins S, Martinez-Botas R, 2007, Dynamic modelling of a SOFC-GT hybrid system for transport applications, European ELE-Drive Transportation Conference EET-2007
Hakeem I, Su C-C, Costall A, et al., 2007, Effect of volute geometry on the steady and unsteady performance of mixed-flow turbines, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART A-JOURNAL OF POWER AND ENERGY, Vol: 221, Pages: 535-550, ISSN: 0957-6509
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- Citations: 19
Szymko S, McGlashan NR, Martinez-Botas R, et al., 2007, The development of a dynamometer for torque measurement of automotive turbocharger turbines, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART D-JOURNAL OF AUTOMOBILE ENGINEERING, Vol: 221, Pages: 225-239, ISSN: 0954-4070
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- Citations: 19
Rajoo S, Martinez-Botas RF, 2007, Improving energy extraction from pulsating exhaust flow by active operation of a turbocharger turbine, ISSN: 0148-7191
A mixed flow turbine with pivoting nozzle vanes was designed and tested to actively adapt to the pulsating exhaust flow. The turbine was tested at equivalent speed of 48000 rpm with inlet flow pulsation of 40Hz and 60Hz, which corresponds to a 4-stroke diesel engine speed of 1600 rpm and 2400 rpm respectively. The nozzle vane operating schedules for each pulse period are evaluated experimentally in two general modes; natural opening and closing of the vanes due to the pulsating flow and the forced sinusoidal oscillation of the vanes to match the incoming pulsating flow. The turbine energy extraction as well as efficiency is compared for the two modes to formulate its effectiveness. Copyright © 2007 SAE International.
Pesiridis A, Martinez-Botas RF, 2007, Experimental evaluation of active flow control mixed-flow turbine for automotive turbocharger application, 50th ASME Turbo-Expo 2005, Publisher: ASME, Pages: 44-52, ISSN: 0889-504X
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- Citations: 21
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