Evaluation of paralleled generation architectures for civil aircraft applications

The aviation industry has witnessed a technological shift towards the More Electric Aircraft (MEA) concept. This shift has been driven by a number of perceived benefits including performance optimization and reduced life-cycle costs. Increased electrification within MEA has made aircraft electrical networks larger and more complex and this necessitates an increased electrical power offtake from the engine. The paralleling of multiple generation sources across the aircraft is one potential design approach which could help improve engine operability and fuel efficiency within more-electric aircraft platforms. Accordingly, this paper will investigate options for the realization of paralleled generation systems within the context of current design and certification rules. The paper first illustrates, through simulation, that MIL-STD-704F voltage envelopes may be breached for some interconnected electrical architectures under fault conditions. The paper then assesses various solution options to minimize the propagation of transients across the interconnected network and demonstrates their effectiveness with reference to appropriate power quality standards. The paper concludes by providing estimates of the impact of each of these solution options on the total weight of the electrical system, highlighting how different designs and operating strategies can influence the design at a systems level

Inductive interconnecting solutions for airworthiness standards and power-quality requirements compliance for more-electric aircraft/engine power networks

Driven by efficiency benefits, performance optimization and reduced fuel-burn, the aviation industry has witnessed a technological shift towards the broader electrification of on-board systems, known as the More-Electric Aircraft (MEA) concept. Electrical systems are now responsible for functions that previously required mechanical, hydraulic or pneumatic power sources, with a subset of these functions being critical or essential to the continuity and safety of the flight.;This trend of incremental electrification has brought along benefits such as reductions in weight and volume, performance optimization and reduced life-cycle costs for the aircraft operator. It has however also increased the necessary engine power offtake and has made the electrical networks of modern MEA larger and more complex. In pursuit of new, more efficient electrical architectures, paralleled or interconnected generation is thought to be one platform towards improved performance and fuel savings.;However, the paralleling of multiple generation sources across the aircraft can breach current design and certification rules under fault conditions. This thesis proposes and evaluates candidate interconnecting solutions to minimize the propagation of transients across the interconnected network and demonstrates their effectiveness with reference to current airworthiness standards and MIL-STD-704F power quality requirements.;It demonstrates that inductive interconnections may achieve compliance with these requirements and quantifies the estimated mass penalty incurred on the electrical architecture, highlighting how architectural and operating strategies can influence design options at a systems level. By examining the impact of protection operation speed on the electrical network, it determines that fast fault protection is a key enabling technology towards implementing lightweight and compliant interconnected architectures.;Lastly, this thesis addresses potential implications arising from alternate standards interpretations within the framework of interconnected networks and demonstrates the impact of regulatory changes on the electrical architecture and interconnecting solutions.Driven by efficiency benefits, performance optimization and reduced fuel-burn, the aviation industry has witnessed a technological shift towards the broader electrification of on-board systems, known as the More-Electric Aircraft (MEA) concept. Electrical systems are now responsible for functions that previously required mechanical, hydraulic or pneumatic power sources, with a subset of these functions being critical or essential to the continuity and safety of the flight.;This trend of incremental electrification has brought along benefits such as reductions in weight and volume, performance optimization and reduced life-cycle costs for the aircraft operator. It has however also increased the necessary engine power offtake and has made the electrical networks of modern MEA larger and more complex. In pursuit of new, more efficient electrical architectures, paralleled or interconnected generation is thought to be one platform towards improved performance and fuel savings.;However, the paralleling of multiple generation sources across the aircraft can breach current design and certification rules under fault conditions. This thesis proposes and evaluates candidate interconnecting solutions to minimize the propagation of transients across the interconnected network and demonstrates their effectiveness with reference to current airworthiness standards and MIL-STD-704F power quality requirements.;It demonstrates that inductive interconnections may achieve compliance with these requirements and quantifies the estimated mass penalty incurred on the electrical architecture, highlighting how architectural and operating strategies can influence design options at a systems level. By examining the impact of protection operation speed on the electrical network, it determines that fast fault protection is a key enabling technology towards implementing lightweight and compliant interconnected architectures.;Lastly, this thesis addresses potential implications arising from alternate standards interpretations within the framework of interconnected networks and demonstrates the impact of regulatory changes on the electrical architecture and interconnecting solutions

Demonstration of fast-acting protection as a key enabler for more-electric aircraft interconnected architetctures

Driven by anticipated fuel-burn and efficiency benefits, the more-electric aircraft (MEA) concept is a technological shift in the aviation industry, which seeks to replace mechanical, hydraulic and pneumatic functions with electrical equivalents. This shift has greatly increased the electrical power demands of aircraft and has made MEA networks larger and more complex. Consequently, new and more efficient electrical architectures are required, with interconnected generation potentially being one design approach that could bring improved performance and fuel savings. This study discusses the current state of interconnected generation in the aviation industry and key technological advances that could facilitate feasible interconnection options. This study demonstrates that interconnected systems can breach certification rules under fault conditions. Through modelling and simulation, it investigates the airworthiness-requirements compliance of potential impedance solutions to this issue and quantifies the potential impact on system weight. It concludes by identifying fast fault clearing protection as being a key enabling technology that facilitates the use of light-weight and standards-compliant architectures

Innovation for a circular economy : exploring the adoption of PSS by UK companies in the baby products sector

Several authors have commented on the relatively slow rate at which Product Service Systems (PSS) have been adopted in B2B networks. Despite some prominent examples, such as the provision of integrated lighting systems to Sainsbury’s (supermarket chain) by Parkersell in the UK, and the ‘pay per copy’ (lease and take back) systems provided by copier companies such as Xerox and Canon, PSS has not been widely adopted even though the business case seems sound. Consequently, the question of identifying and overcoming barriers to PSS adoption has become an important research topic. In this study we explore barriers to the adoption of PSS in the UK baby products industry using a qualitative research design employing in-depth interviews with baby products suppliers (manufacturers) and buyers (retailers). The novelty of the approach adopted in this study is that key concepts from the Industrial Networks Approach are used to frame the analysis. Buyers and suppliers of baby products acknowledge the value of the PSS approach, but PSS adoption is found to require considerable adaptation to conventional patterns of inter-organizational interaction

Computational Fluid Dynamics study of Airflow through a Car's Radiator

Computers are now an integral part of engineering helping us achieve solutions to evermore complex tasks. This study aims to better understand computer modeling and analysis using the necessary software for Fluid Dynamics and computer modeling. The study will also help better understand the current designs of automotives andfluid mechanics in general. There are many ways that performance of a carcan be measured, by wind-tunnel testing, longer empirical studies or CFD but most of these concentrate on optimization of external fluid-flow. This study sees the relationship between airflow under and over the hood. At the end of this report, the author will conclude on the analysis and research that has been done to look at the approach of the using CFD in order to study and understand fluid flow through different circumstances and for computer modeling. Hence, better understand today's technological advances

Design and Stability of an On-Orbit Attitude Control System Using Reaction Control Thrusters

Basic principles for the design and stability of a spacecraft on-orbit attitude control system employing on-off Reaction Control System (RCS) thrusters are presented. Both vehicle dynamics and the control system actuators are inherently nonlinear, hence traditional linear control system design approaches are not directly applicable. This paper has two main aspects: It summarizes key RCS design principles from earlier NASA vehicles, notably the Space Shuttle and Space Station programs, and introduces advances in the linear modelling and analyses of a phase plane control system derived in the initial development of the NASA's next upper stage vehicle, the Exploration Upper Stage (EUS). Topics include thruster hardware specifications, phase plane design and stability, jet selection approaches, filter design metrics, and RCS rotational maneuver logic