| 1. |
- Avellan, Rickard, 1976, et al.
(författare)
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AN ASSESSMAn assessment of a turbofan engine using catalytic interturbine combustionENT OF A TURBOFAN ENGINE USING CATALYTIC INTERTURBINE COMBUSTION
- 2009
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Ingår i: 2009 ASME Turbo Expo; Orlando, FL; United States; 8 June 2009 through 12 June 2009. - 9780791848852 ; 2009:GT2009-59950, s. 383-392
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Konferensbidrag (refereegranskat)abstract
- The potential for using catalytic combustion in aero engines is discussed. Some preliminaries relating to NOx formation and material capabilities are analyzed. Various means to integrate catalytic combustors in aero engines are described. In particular, catalytic interturbine combustion is investigated both in terms of technical feasibility and through a preliminary design exercise. A thermodynamic design point study is presented analyzing a configuration with a combustor located concentrically around the engine core receiving pressurized air through an interstage high pressure compressor bleed. A parameter study of the compressor bleed ratio is presented for the configuration. A substantial reduction in NOx emissions at the expense of an increase in mission fuel consumption is observed.
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| 2. |
- Avellan, Rickard, 1976, et al.
(författare)
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Boxprop, a forward-swept joined-blade propeller
- 2013
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Ingår i: ISABE-2013-1108.
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Konferensbidrag (refereegranskat)abstract
- This article describes the Boxprop, a new high-speed propeller concept with forward swept joined-blade for future transport aircraft applications. Both numerical and experimental investigations of the joined-blade propeller were carried out at GKN Aerospace and Chalmers University in order to answer some of the fundamental questions relating to aerodynamic performance and mechanical integrity. The results show that the Boxprop concept works as intended and in particular that rapid prototyping methods using polymeric materials are suitable for early product development, even for functional testing of high speed propellers. Furthermore, based on the positive outcome of the experimental work described in this article, the next development step can be started by initiating the design of the counter-rotating Boxprop and wind tunnel test stand to proof the concept at TRL 3.
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| 3. |
- Avellan, Rickard, 1976
(författare)
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On the Design of Energy Efficient Aero Engines: Some Recent Innovations
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the light of the energy crisis of the 1970s, the old aerospace paradigm of flying higher and faster shifted towards the development of more energy efficient air transport solutions. Today, the aeronautical research and development community is more prone to search for innovative solutions, in particular since the improvement rate of change is decelerating somewhat in terms of energy efficiency, which still is far from any physical limits of aero engine and aircraft design. The Advisory Council for Aeronautics Research in Europe has defined a vision for the year of 2020 for aeronautical research in Europe which states a 50% reduction in CO2, 80% reduction in NOx and a 50% reduction in noise.Within this thesis work, methods for conceptual design of aero engines and aircraft performance have been developed and applied to evaluate some innovative aero engine concepts that have the potential to fulfil or even surpass society’s expectations on the aerospace industry in the future. In particular, the impact of a varying engine size and weight on the aircraft performance has been modelled in order to quantify the fuel consumption of different aero engine concepts. Furthermore, methods for designing and analyzing propeller performance have been developed. The methods have been incorporated into a multidisciplinary optimization environment which gives the benefit of interdisciplinary quantification of design changes and the impact of those on energy efficiency.The potential of the variable cycle engine for medium range jets were studied and the results showed a quite large reduction in fuel consumption compared to the conventional turbofan engine. Furthermore, the inter-turbine reheated aero engine concept was evaluated and the results indicated a large NOx reduction potential at almost the same energy efficiency as the conventional engine. The idea of applying catalytic combustion in aero engines was also studied showing potential of significant reductions of NOx. Finally, an innovative propeller design based on Prandtl’s work in the 1920s is suggested and discussed.This work has contributed with new methods for conceptual aero engine design that are in use within the industry and academia. The results from the studies concerning innovative aero engine concepts show that major improvements in terms of energy efficiency and emissions still are possible for the aerospace industry to achieve.
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| 4. |
- Avellan, Rickard, 1976, et al.
(författare)
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Preparing for Proof-of-concept of a Novel Propeller for Open Rotor Engines
- 2015
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Ingår i: ISABE-2015-20097.
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Konferensbidrag (refereegranskat)abstract
- This article describes the development of a novel high-speed propeller concept. Large-scale propeller tests are extremely expensive and thus not appropriate at early R&D development phases. A convenient approach is to use computational methods validated by small-scale tests with propellers manufactured from low-cost materials and rapid manufacturing methods. The present paper is describing this cross validation work explaining differences between numerics and experiments. Preferred materials and manufacturing methods for high-speed future wind tunnel tests are discussed. We also discuss the progress of development of the aerodynamic design of the concept propeller.
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| 5. |
- Avellan, Rickard, 1976
(författare)
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Towards Environmentally Friendly Aero Engines
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Since the introduction of subsonic jet driven commercial aircraft, incremental improvements in overall efficiency has been a driving requirement as well as a selling argument for the engine industry. The historical overall efficiency improvement is the result of continuous advances in aerodynamic design, increase of overall pressure ratios, turbine inlet temperatures and propulsive efficiencies in parallel with the development of stronger and lighter materials. The bypass jet engine technology provided a major improvement in specific fuel consumption and noise levels. Since its introduction, the turbofan engine has manifested the aero engine industry standard.The objectives of this work have been to evaluate a number of potential aero engine technologies, with respect to the future environmental goals and the reference technology level that is used today. In order to achieve this, methods for assessing subsonic and transonic airplane aerodynamics, operating cost, aero engine emissions and noise have been developed. In particular the opportunities provided by the geared turbofan engine (GTF) are carefully analysed and compared to the advanced direct drive turbofan (DDTF) engine. Although estimated improvements are considerably lower than provided by leading engine manufacturers the engine cycle still provides a valuable reduction in fuel burn. More importantly, the GTF engine allows a substantial reduction in engine noise at a considerably lower fuel penalty than achievable by the DDTF engine configuration. Several innovative concepts, such as the intercooled recuperated aero engine, distributed propulsion, open rotor engines, catalytic combustion as well as the use of alternative fuels are discussed.It is observed that today’s jet driven commercial transport airplanes, despite six decades of airplane and engine evolution, are operating at about the same energy efficiency as the best piston driven engines of the 1940s. This is a consequence of the high productivity requirement posed on today’s commercial aviation. It seems reasonable to assume that a considerable potential for improving energy efficiency exists if society will allow a reduction in aviation productivity by accepting increased travel times.
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| 6. |
- Capitao Patrao, Alexandre, 1988, et al.
(författare)
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An Optimization Platform for High Speed Propellers
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- To improve the efficiency by which current power plants translate jet energy into useful thrust the use of turboprop and in particular open rotor aircraft are being revisited. One challenge in association with developing new powerplants for such aircraft is high speed propeller design in general and noise prediction in particular.The Boxprop was invented in 2009 by GKN Aerospace in order to mitigate the effects of the tip vortex on noise and to improve upon the aerodynamics of a conventional propeller blade. The Boxprop is composed of a double-bladed propeller joined at the tips, and the design has the potential to eliminate the tip vortex, and thereby decrease that particular noise source. The complex and highly three-dimensional shape of an advanced propeller blade is challenging to model with classical propeller design methods, requiring instead more sophisticated optimization methods.This paper presents an optimization platform developed for high speed propellers, and illustrates its use by performing a reduced aerodynamic optimization of the Boxprop. The optimization process starts by performing a Latin Hypercube Sampling of the design space, and analyzes the resulting geometries using CFD. A meta-model employing radial basis functions is then used to interpolate on the obtained CFD results, which the GA uses to find optimal candidates along the obtained Pareto front. These designs are then evaluated using CFD, and their data added to the meta-model. The process iterates until the meta-model converges.The results of this paper demonstrate the capability of the presented optimization platform, and applying it on the Boxprop has resulted in valuable design improvements and insights. The obtained designs show less blade interference, more efficiently loaded blades, and less produced swirl. The methodology for geometry generation, meshing and optimizing is fast, robust, and readily extendable to other types of optimization problems, and paves the way for future collaborative research in the area of turbomachinery.
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| 7. |
- Capitao Patrao, Alexandre, 1988, et al.
(författare)
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Wake and Loss Analysis for a Double Bladed Swept Propeller
- 2016
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Ingår i: Proceedings of ASME Turbo Expo 2016: Turbine Technical Conference and Exposition, Seoul, South Korea, Jun 13-17, 2016. ; 1
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Konferensbidrag (refereegranskat)abstract
- Inspired by Prandtl’s theory on aircraft wings with minimum induced drag, the authors introduced a double-bladed propeller, the Boxprop, intended for high-speed flight. The basic idea is to join the propeller blades pair-wise at the tip to improve aerodynamics and mechanical properties compared to the conventional propeller. The rather complex geometry of the double blades gives rise to new questions, particularlyregarding the aerodynamics.This paper presents a propeller wake energy analysis method which gives a better understanding of the potential performance benefits of the Boxprop and a means to improve its design.CFD analysis of a five bladed Boxprop demonstrated its ability to generate typical levels of cruise thrust at a flight speed of Mach 0.75. The present work shows that the near tip velocity variations in the wake are weaker for this propeller than a conventional one, which is an indication that a counter rotatingpropeller designed with a Boxprop employed at the front may exhibit lower interaction noise.
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| 8. |
- Capitao Patrao, Alexandre, 1988, et al.
(författare)
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Wake Energy Analysis Method Applied to the Boxprop Propeller Concept
- 2018
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Ingår i: Aerospace Science and Technology. - : Elsevier BV. - 1270-9638. ; 79, s. 689-700
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Tidskriftsartikel (refereegranskat)abstract
- Inspired by Prandtl's theory on aircraft wings with minimum induced drag, the authors have introduced a double-bladed propeller, the Boxprop, intended for high-speed flight. The basic idea is to join the propeller blades pairwise at the tip to decrease tip vortex strength and improve mechanical properties compared to a conventional propeller. The present work develops a wake analysis method allowing an energy breakdown of the flow as well as making the irreversibility of the flow explicit by using the entropy lost work concept. The method quantifies the strength of flow features such as tip vortices and wakes in terms of engine power. In contrast to existing work, this method removes assumptions of uniform flow, no radial flow, and constant static pressure in the propeller jet. The results of the wake analysis method can be summarized into three key findings 1) the energy in the tip-vortex of the Boxprop design is comparatively speaking non-existent, 2) the swirl energy level of the Boxprop is higher and this turbomachine is thus more in need of a downstream counter-rotating blade to recover the energy, 3) the Boxprop develops a much larger part of its thrust closer to the hub. Analysis of this aspect of the flow reveals that blade interference approaching the tip, where the blades in a pair are more closely spaced, is quite pronounced. In turn, this indicates that maximum efficiency Boxprop designs are more likely to be obtained by having larger axial separation of the two blades.
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| 9. |
- Ekstrand, Henrik, 1975, et al.
(författare)
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Derated Climb Trajectories for Subsonic Transport Aircraft
- 2009
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Ingår i: PROCEEDINGS XIX INTERNATIONAL SYMPOSIUM ON AIR BREATHING ENGINES.
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Konferensbidrag (refereegranskat)abstract
- Minimising the overall operating cost with regard toengine deterioration during takeoff by using deratedtakeoff thrust is well understood by aircraft andengine manufacturers. Some aircraft have thepossibility to use derated climb thrust as well, whichis not always fully understood by the operators. Thepossibility of using derated climb thrust for reducingmaintenance costs is discussed. It is shown that byusing derated climb thrust D2, the HPT blade life canbe increased by 7 % at the expense of a 0.7 %increase in fuel consumption during the climb phase,affecting the overall flight mission fuel consumptionby approximately 0.1 %.
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| 10. |
- Grönstedt, Tomas, 1970, et al.
(författare)
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Catalytic Burner Device
- 2007
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The invention relates to gas turbine engine comprising a first flow passage, and main combustion means in the first flow passage. The engine further comprises a second flow passage, and first catalytic combustion means in the second flow passage, wherein the second flow passage can communicate with the first flow passage at at least one upstream passage junction upstream of the main combustion means and upstream of the first catalytic combustion means, and the second flow passage can communicate with the first flow passage at at least one downstream passage junction downstream of the main combustion means and downstream of the first catalytic combustion means.
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