Recent Progress in Some Aircraft Technologies

The book describes the recent progress in some engine technologies and active flow control and morphing technologies and in topics related to aeroacoustics and aircraft controllers. Both the researchers and students should find the material useful in their work

Aeronautical engineering: A special bibliography with indexes, supplement 80

This bibliography lists 277 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1977

10th EASN International Conference on Innovation in Aviation & Space to the Satisfaction of the European Citizens

This Special Issue book contains selected papers from works presented at the 10th EASN (European Aeronautics Science Network) International Conference on Innovation in Aviation & Space, which was held from the 2nd until the 4th of September, 2020. About 350 remote participants contributed to a high-level scientific gathering providing some of the latest research results on the topic, as well as some of the latest relevant technological advancements. Eleven interesting articles, which cover a wide range of topics including characterization, analysis and design, as well as numerical simulation, are contained in this Special Issue

Propulsion Controls, 1979

The state of the art of multivariable engine control is examined in order to determine future needs and problem areas and to establish the appropriate roles of government, industries, and universities in addressing these problems

Aeronautical engineering. A continuing bibliography with indexes

This bibliography lists 326 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1982. Topics on aeronautical engineering and aerodynamics such as flight control systems, avionics, computer programs, computational fluid dynamics and composite structures are covered

Impact of electrically assisted turbocharging on the transient response of an off-highway diesel engine

Engine boosting via turbocharging is a method to increase the engine power output with minimal or no increase in engine parasitic, frictional and pumping losses. Turbocharging in conjunction with engine down-sizing and down-speeding allows a reduction of engine fuel consumption, while maintaining a high engine power output. However, turbocharging introduces a lag in engine transient response, caused by the finite amount of time required by the turbocharger to accelerate, which has to be minimized. Electric turbocharger assistance consists of coupling an electric motor/generator to a standard turbocharger. The scope of the motor/generator is to increase the power available to accelerate the rotor assembly, so that the time to boost is reduced. The motor/generator could also be utilized to brake the turbocharger to control boost and avoid over-speeds, thus replacing the conventional waste-gate. Furthermore, electric assistance allows turbocompounding to be implemented. Turbocompounding improves the engine efficiency by utilizing the turbine and motor/generator to recuperate additional exhaust flow energy. In this thesis, the electric turbocharger assistance impact on the turbocharger and engine performance is studied. An electrically assisted turbocharger prototype has been developed by industrial partners and it has been tested by the author of this thesis. The performance of the turbocharger turbine and motor/generator has been characterized over the full speed range and the impact of the electric assistance on the turbine flow has been investigated experimentally. It has not been possible to characterize the turbine up to choking conditions, so the data has been extrapolated via a mean-line model. The performance data obtained has been utilized to generate a model of the assisted turbocharger, which has been coupled to a one-dimensional model of a non-highway 7-litre diesel engine. This model has been utilized to study the impact of electric turbocharger assistance on the engine transient performance. The electrical machine characterization revealed that the switched reluctance motor/generator operates efficiently up to a speed of 135,000 rev/min, making it one of the fastest running switched reluctance machines of this size. The peak machine efficiency is 93% (excluding the turbocharger bearing losses) and the maximum power output measured is 5.3 kW in generating mode and 4.3 kW in motoring mode. The motor/generator rotor aerodynamic drag loss has been calculated via computational fluid dynamics software and has been found to be 63 W at 140,000 rev/min. Via a novel experimental technique, it has been possible to characterize the turbocharger turbine down to an expansion ratio of 1.00. This experiment revealed that the mass flow rate drops to zero at an expansion ratio higher than unity and that below this critical pressure ratio the turbine flow is reversed. The characterization of the turbine during speed transients showed that the operating point on the performance map deviates from the quasi-steady line. This indicates that minor unsteady effects occur in the turbine and exhaust manifold flow. A further experiment revealed that the motor/generator torque oscillations have a negligible impact on the turbine performance. The engine simulations showed that the ideal electric assistance motoring power for this application is in the 5 to 10 kW range. A 5 kW machine reduces the engine speed drop, which occurs when the engine load is suddenly increased, by up to 83%, depending on the initial load and load step size, and reduces the time to recover the original speed by up to 86%. The simulations also revealed that electric assistance is more effective than the turbine variable geometry system in improving the engine transient response, but the variable geometry system is useful to optimize boost for engine specific fuel consumption over different engine loading conditions.Open Acces

Aeronautical engineering: A continuing bibliography with indexes (supplement 119)

This bibliography lists 341 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1980. Abstracts on the engineering and theoretical aspects of design, construction, evaluation, testing, operation, and performance of aircraft (including aircraft engines) and associated components, equipment, and systems are presented. Research and development in aerodynamics, aeronautics, and ground support equipment for aeronautical vehicles are also presented

Gas turbine shaft over-speed / failure modelling: aero/thermodynamics modelling and overall engine system response

Gas turbine design needs of high-speed turbomachinery whose layout is organised in compressor-turbine pairs mechanically linked by concentric shafts. The mechanical failure of a shaft leads to compressor-turbine decoupling provoking the acceleration of the free-running turbine. In view of such scenario, it is of paramount importance to guaranty the mechanical integrity of the turbine, in terms of high energy debris release. Certification authorities require proof that any possible failure will be contained; admitting the reliable simulation capability of the event as certification strategy. The objectives of this research activity have aimed at the development of reliable simulation tools based on analytical and semi-empirical models. The integration of all the different models/modules together in an “all-in-one” tool provides the sponsor company with the capability to simulate and assess various shaft over-speed scenarios during the early stages of an engine's design and development program. Shaft failure event cannot be understood unless engine components interaction and fast transient effects are taken into account in a global manner. The high vibration level consequence of the breakage, or the thermodynamic mismatch due to the rapid free-running compressor deceleration, trigger the surge of the compression system which affects to the performance of every engine component. Fully-transient simulation capability to model compression system post-stall performance and secondary air system behaviour has been developed. Component map prediction tools have been created for compressor reverse flow performance and turbines affected by inlet distorted flows. The development of the so-called “all-in-one” simulation tool has been completed and it has been applied to the modelling of a real case of shaft failure. Reliable prediction of thermodynamic properties evolution and over-speeding turbine terminal speed have been shown. The robustness and flexibility of the simulation tool have been demonstrated by its application to different theoretical scenarios

Aeronautical Engineering: A continuing bibliography with indexes, supplement 99

This bibliography lists 292 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1978

Aeronautical Engineering: A continuing bibliography, supplement 124

This bibliography, lists 450 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1980