Browsing by Author "Lawson, Craig;"

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    Benefit and performance impact analysis of using hydrogen fuel cell powered e-taxi system on A320 class airliner
    (Cambridge University Press, 2019-04-05) Stockford, Jack andrew; Lawson, Craig;; Liu, Z
    This paper presents the work carried out to evaluate the benefits and performance impacts of introducing a hydrogen fuel cell powered electric taxiing system to a conventional short-haul aircraft. Tasks carried out in this research and reported in this paper include the initial system design, hydrogen tank initial sizing, calculation of the impact on fuel burn and emissions and the evaluation of the effects on Direct Operating Cost (DOC). The Airbus A320 has been selected as the datum aircraft for sizing the system, and the benefits analysis is particularly focused on the fleet composition and financial data of a Europe-based, low-cost, large-scale A320 family operator in 2016. The maximum power capacity of 400 kW has been sized based on the rolling friction coefficient of 0.02. Based on the operator’s 2016 financial, up to 1% fuel reduction can be achieved using the proposed system and the reduction in total maintenance cost is expected to be up to 7.3%. Additionally, up to 5.97% net profit improvement is estimated in comparison with the annual after-tax profit of the datum operator in 2016
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    Conceptual design of a next generation supersonic airliner for low noise and emissions
    (AIAA, 2023-01-19) Villena Munoz, Cristina; Bonavolontà, Giordana; Lawson, Craig;; Riaz, Atif
    The development of an innovative, medium-range supersonic airliner to meet low drag, low emissions and LTO noise requirements is presented in this paper, including a multi-disciplinary design framework targeting firstly to meet at least the current noise regulations for subsonic aircraft during take-off and landing and secondly to reduce the emission levels. The aircraft is designed to fly 4000 nm at Mach 2.2, carrying 100 passengers. The work contributes to the EU SENECA ((LTO) noiSe and EmissioNs of supErsoniC Aircraft) project, which aims to design different SST (SuperSonic Transport) aircraft platforms to investigate the emissions, the noise and the global environmental impact of supersonic aviation. Results from SENECA can support ICAO in the process of creating future certification requirements as well as form legislation guidelines specifically for the future supersonic commercial aircraft. The technical work includes the assessment of different aircraft-engine configurations, in terms of engine number and positions, on typical flight missions. This enables the evaluation of the baseline layouts that represent the best compromise among payload-range capability, aerodynamic performance, weight and noise. A multi-disciplinary airframe-engine integrated design is carried out in order to pursue a comparative analysis focusing on take-off noise for the different aircraft-engine combination platforms. Lastly, the investigation of the potential use of variable noise reduction systems (VNRS), such as a FADEC controlled thrust reduction during take-off, called Programmed Lapse Rate (PLR) is carried out to study their impact in the mitigation of the resultant noise in the airport environment.
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    Conceptual design of supersonic aircraft to investigate environmental impact
    (AIAA, 2024-01-04) Villena Munoz, Cristina; Lawson, Craig;; Riaz, Atif; Jaron, Robert
    The SENECA ((LTO) noiSe and EmissioNs of supErsoniC Aircraft) project, funded under the EU Horizon 2020 framework, is dedicated to the exploration of future designs for supersonic business jets and supersonic commercial airliners, placing significant emphasis on minimising landing and take-off noise and mitigating emissions. The research outcomes are intended to inform discussions at ICAO level, providing scientific support to enhance the European perspective on regulatory requirements for novel supersonic aircraft. The overall aim of the research is the development of four different supersonic transport aircraft platforms, comprising both airframes and engines design. These aircraft configurations range from supersonic business jets, designed for cruise Mach numbers of 1.4 and 1.6, to large airliners capable of accommodating 100 passengers, with cruise Mach numbers of 1.8 and 2.2. In pursuit of the next generation of environmentally sustainable supersonic civil aircraft, the research employs a multi-disciplinary design optimisation strategy. This strategy primarily focuses on meeting the current noise regulations for subsonic aircraft during landing and take-off and secondly on reducing emissions levels. This paper details the conceptual development of the platforms specifications for the four supersonic aircraft designed within SENECA project. These specifications include geometrical and configuration data, performance characteristics, as well as mission trajectories and profiles.
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    Design manufacturing integration and flight testing of a health monitoring system for a prototype unmanned airborne vehicle
    (SAGE, 2013-05-08) Lawson, Craig;; Al Monterzino, Guido
    This article describes the design, development, build and flight testing of a health monitoring system for the landing gear and the electrical power system on board the Demon prototype unmanned airborne vehicle. Demon is a flying technology demonstrator which successfully flew in September 2010. The Demon can achieve pitch and roll control without the use of hinged control surfaces, by instead using fluidic devices based on the Coanda effect, attaining low-maintenance, high-manoeuvrability operations. A vehicle health monitoring system was added on board between the first and the second flight test campaigns. The integration of the health monitoring system into the vehicle is discussed as a whole. The key health monitoring sub-systems include data logging and real-time measurement of several parameters. This includes systems to measure Voltage and current from the main batteries, landing gear stress, suspension travel, wheel hub acceleration and shock absorber pressure. Wherever possible, the use of commercially available components was maximised to minimise development time and cost. Some example results of system health monitoring during flight trials are presented
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    Development of a tool to study aircraft trajectory optimisation in the presence of icing conditions
    (SAGE Publications (UK and US), 2014-10-10) Shinkafi, Ahmed; Lawson, Craig;
    With the increasing demand of air travel, the impact on the environment due to aviation has shown a significant increase in recent times. As a result, there is a growing demand for new technologies and flight procedures that will enable aircraft operators to burn less fuel and reduce the adverse effect of aviation on the environment. Conventional approaches to trajectory optimisation do not take the effect of aircraft systems into account. Neglecting these effects may be inadequate, especially when one considers real aircraft operations in real weather scenarios. This research has developed a tool capable of simulating aircraft ice protection performance for trajectory optimisation, which enables the development of a decision making process dependent on weather within the flight management system, thus transforming the conventional ice protection system to a more intelligent system. Presently, thermal ice protection methods are the leading ice protection technology on most of the medium and large transport aircraft. An enhanced aircraft anti-icing model was developed based on Messinger mass and energy balance method for thermal anti-icing. The tool developed in this work can calculate the total water catch and evaluate power requirement due to icing under a wide range of meteorological conditions. The model was successfully integrated with a trajectory optimisation framework for independent assessment of fuel penalty due to icing and investigation of pollutant emissions reduction through aircraft trajectory optimisation. A case of typical departure from London Airport Heathrow was optimised for fuel burn and time. The preliminary results show that when operating in known icing condition, including icing parameters in the optimisation loop could give as much as 2.1% fuel savings.
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    DFA/MOST results
    (Cranfield University, 2017-01-06 15:41) Judt, David; Lawson, Craig;; Lockett, Helen
    Results for the empirical analysis of the assembly tasks using DFA and basic MOST
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    Effects of more electric systems on fuel tank thermal behaviour
    (Société de l'Electricité, de l'Electronique et des Technologies de l'Information et de la Communication, 2019-12-31) van Heerden, Stevan; Judt, David M.; Lawson, Craig;; Bosak, David
    With the advent of more electric airframe systems and ultra-high bypass ratio turbofan engines, there is growing interest in the associated thermal implications. In this research project, an aircraft level model that is appropriate to enable investigations into novel thermal management solution on future aircraft is developed. In this paper, an investigation into the effects of more electric systems on the thermal behaviour of fuel tanks in civil transport aircraft is presented.Specifically, the influence of the heat generated by conventional and more electric systems on the fuel tank was modelled and simulated. A fuel thermal model was developed, which consists of a tank geometry representation, coupled to a module that calculates remaining mission fuel mass. The systems architectures are represented by connected thermal component models. Standard approaches were then employed to estimate convection and conduction heat transfer coefficients at the tank interfaces. The model solves 1-D transient heat equations, coupling heat transfer and material heat capacity via heat flux balances. The thermal and systems models were integrated into a baseline aircraft performance model, which was used to dynamically simulate the tank thermal behaviour during representative missions. The initial results indicate that switching to more electric environmental control and iceprotection systems likely have negligible thermal impact on the bulk fuel temperature. However, some benefits may be obtained regarding safety and certification, but this requires further study.
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    Electrical load-sizing methodology to aid conceptual and preliminary design of large commercial aircraft
    (Sage, 2014-05-13) Seresinhe, Ravinka; Lawson, Craig;
    The importance of the more electric aircraft has been highlighted in many publications, projects and industrial presentations. By definition, the more electric aircraft concept achieves the majority of the required system functionality by using electrically powered sub-systems and components. This manifests itself in much higher electrical power demands on-board aircraft, compared to conventional architectures. This presents many challenges in the design process. To alleviate the risk and choose the optimum architectures for the systems on the aircraft, it is essential to incorporate the characteristics and possible configurations of the electrical network in the conceptual and preliminary design stages. Hence the current practice of performing an electrical load analysis at the detailed design stage is not adequate. To address this gap, this paper presents a viable and robust methodology to define requirements, size components and systems and calculates the electric power requirements at the preliminary design stages. The methodology uses the conventional aircraft, systems and components as the baseline and uses mathematical techniques and logical sequences of component operation, developed through the research, to size electrical load profiles for conventional aircraft. It then adapts this result to the more electric aircraft concept by adding key components that would account for the difference between a conventional system and a more electric system. The methodology presented here makes the design process more robust and aids the choice of the optimum design for the aircraft.
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    Experimental investigation into aircraft system manual assembly performance under varying structural component orientations
    (SAGE, 2019-10-18) Judt, David M.; Lawson, Craig;; Lockett, Helen L.
    Installation of aircraft wing systems is a bottleneck in the assembly process. This phase is typically composed of many work packages, taking hundreds of man-hours per wing. In addition to this volume of work, tasks are specialized and completed in a difficult environment in terms of access and visibility. In current industrial practice, the wing is mounted horizontally on a transport trolley, which exposes the workforce to prolonged periods of overhead working. Future wing designs may consider a pre-equipping build philosophy, where systems are installed to major structure assemblies before the wing box is assembled. This allows for a change in the orientation and position of the major structure and provides new freedoms in assembly station design and layout. This research presents results of experiments to investigate manual assembly performance of aircraft wing systems, under varying wing structure orientation. A mock-up of a section of an A320 aircraft wing front spar, mounted on a rotation device, functions as the testbed. Manual installation activities are then conducted to emulate real aircraft system equipping for electric harnesses, raceways and hot air ducts. The results show a best-case assembly performance change of 36% for electric system installation activities of cable harnesses and raceway housing components. Tilted and horizontal orientations of the structure show the highest time reductions, with the vertical orientation either non-conclusive or increasing the assembly time. The outcomes of this study are intended to aid in effective trade-off decision making for future wing systems and assembly station layouts from the perspective of structural orientation and assembly task interaction.
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    A generic mission-level flight control surface EMA power consumption simulation tool
    (MDPI, 2022-05-26) Fu, Jingcheng; van Heerden, Albert S. J.; Judt, David; Lawson, Craig;
    The use of electromechanical actuators (EMAs) for aeronautical applications promises substantial benefits regarding efficiency and operability. To advance the design of power electronics and secondary power supply, there is a need for the ability to swiftly study the effects of aircraft mission and operational aspects on the actuator energy consumption. Pursuant to this, the aim of the work presented in this paper is twofold: (i) to build a generic mission-level flight control surface EMA power consumption simulation framework and (ii) to apply this framework to a case study involving a small all-electric aircraft, in which selected factors that impact energy consumption are investigated. The core of the framework comprises physics-based EMA power estimators, linked with a six-degree-of-freedom flight dynamics and control simulation module. The case study results show that the actuator power consumption correlates positively with the proportional gains in the flight control system but is inversely proportional to the trajectory radius and linearly dependent on turbulence intensity. The developed framework could aid in the selection of the actuator, as well as in the optimisation of airborne electronics and secondary power supply.
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    Improving the operating efficiency of the more electric aircraft concept through optimised flight procedures
    (Springer, 2018-09-22) Seresinhe, Ravinka; Lawson, Craig;; Madani, Irfan
    The increasing awareness of the environmental risks and costs due to the growing demand in aviation has prompted both academic and industrial research into short-term and long-term technologies which could help address the challenges. Among these, the more electric aircraft has been identified as a key design concept which would make aircraft more environmentally friendly and cost effective in the long run. Moreover, the notion of free-flight and optimised trajectories has been identified as a key operational concept which would help curb the environmental effects of aircraft as well as reduce overall costs. The research in this paper presents a methodology in which these two concepts can be coupled to study the benefits of more electric aircraft (MEA) flying optimised trajectories. A wide range of issues from aircraft performance, engine performance, airframe systems operation, power off-take penalties, emission modelling, optimisation algorithms and optimisation frameworks has been addressed throughout the study. The case study is based on a popular short haul flight between London Heathrow and Amsterdam Schiphol. The culmination of the study establishes the advantage of the MEA over conventional aircraft and also addresses the enhanced approach to the classical aircraft trajectory optimisation problem. The study shows that the operation procedures to achieve a minimum fuel burn are significantly different for a conventional aircraft and MEA. Trajectory optimisation reduced the fuel burn by 17.4% for the conventional aircraft and 12.2% for the more electric compared to the respective baseline cases. Within the constraints of the study, the minimum fuel burn trajectory for the MEA consumed 9.9% less fuel than the minimum fuel burn trajectory for the conventional aircraft.
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    Predicting cavitation erosion on two-stage pumps using CFD
    (IEEE, 2022-10-28) Verhulst, Tedja; Ng, Eddie Yin-Kwee; Chung, Yongmann; Judt, David; Lawson, Craig;
    Cavitation is a common problem that occurs in pumps which reduces its useful life and bring increased operating costs to the user. A study of cavitation erosion on a two-stage centrifugal pump has been carried out using Computational Fluid Dynamics (CFD). Most cavitation studies on pumps have been focused on modelling the severity of cavitation; specifically, on understanding its visual effects and performance penalties. Few works have been carried out to predict the most erosion-sensitive areas inside a pump. The focus of this study is on modelling the permanent damage that would be caused by cavitation and to identify specific areas within the pump which are most susceptible to erosion. The model is first validated against experimental data from another work. Once the simulation has been successfully calibrated, the cavitation simulation is carried out again with the subject pump. Not only does this work extend the findings previous works by predicting cavitation erosion on a two-stage pump, but the pump rotation speed is also varied to observe how the erosion-sensitive areas on the pump changes as a result. A specific focus on the Gray Level Method is carried out to predict the erosion damage on the pump. This technique is chosen as it has been experimentally proven with single-stage radial pumps, using specialized CFD code. It is found that the algorithm used to predict erosion when applied with commercial CFD packages, are useful in distinguishing areas inside the pump which are most vulnerable to erosion damage. The Scherr-Sauer cavitation model coupled with the κ-ω SST turbulence model have been used to run the cavitation simulations.
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    Preliminary design of next generation Mach 1.6 supersonic business jets to investigate landing & take-off (LTO) noise and emissions–SENECA
    (IOP Publishing, 2023-06-28) Mourouzidis, Christos; Del Gatto, Dario; Adamidis, Stylianos; Villena Muñoz, Cristina; Lawson, Craig;; Martinez Corzo, B.; Leyland, P.; Marsh, D.; Lim, L.; Owen, B.
    With the approach of next generation supersonic transport entry into service, new research activities were initiated to support updates on ICAO regulations and certification processes for supersonic transport vehicles. Within this context, the EU Horizon 2020 SENECA project has been launched to investigate the levels of noise and gaseous emissions in the vicinity of airports as well as the global climate impact of next generation supersonic civil aircraft. This paper introduces some of the preliminary outcomes of this investigation. It presents the preliminary design and performance analysis of a Mach 1.6 business jet, following an integrated aircraft-engine design approach. The preliminary design was performed accounting for the limitations posed by future environmental restrictions on respective subsonic vehicles. The market space and mission route definition exercise assumed only "over-sea" supersonic operations, while for "over-land", only subsonic operations where allowed. Parametric studies on engine integrated design demonstrated modest core temperatures while cruising and the significant impact of engine installation on performance. At this first design iteration, assuming current state of the art technology, the Mach 1.6 business jet showed good potential to satisfy the predicted mission requirements while respecting the environmental constraints in terms of Landing & Take-Off (LTO) noise and emissions.
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    Raw post experiment preference data
    (Cranfield University, 2017-01-06 15:41) Judt, David; Lawson, Craig;; Lockett, Helen
    Raw data of participant responses to ranking the position preference order.
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    Raw time results
    (Cranfield University, 2017-01-06 15:41) Judt, David; Lawson, Craig;; Lockett, Helen
    Raw data for the wing D-nose aircraft system assembly time trials
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    Review for state-of-the-art health monitoring technologies on airframe fuel pumps
    (Prognostics and Health Management Society, 2022-01-14) Verhulst, Tedja; Judt, David; Lawson, Craig;; Chung, Yongmann; Al-Tayawe, Osama; Ward, Geoff
    Aircraft maintenance is an essential cost borne by the airline. Improving maintenance practices for day-to-day operations can lead to significant financial savings. The benefits of effective maintenance are derived from the avoided costs caused by unexpected breakdowns and from maximising aircraft flight time transporting passengers. The fuel system is a crucial part of the entire aircraft as it ensures delivery of the fuel to the engine and a key component within this system are the fuel pumps. These airborne fuel pumps are classified between the pumps installed in the airframe fuel system and in the engine fuel system. Past works have investigated the performance characteristics of these pumps during flight, however there are no reviews related to the present Health Monitoring (HM) capabilities under flight conditions. HM refers to the field of diagnosing faults or predicting the remaining useful life (RUL) of the pump and the focus of this review is to highlight the HM technologies suitable for aircraft fuel pumps. This is done by first reviewing the technologies and concepts related to HM of fuel pumps. Second a literature review is carried out on pump and motor faults is carried out, drawing on examples from aerospace and other relevant industries. Section 6: Conclusion, discusses the HM technologies have been applied to aerospace fuel pumps and highlights the gaps in capabilities, based on the findings of the literature review carried out in Section 4: Common Faults and Section 5: HM Sensing Methods to suggest future developments in this field. It was found that there is a large scope for development for the HM airframe fuel pumps, based on reviewing the present state of the art. Furthermore, there are no clear strategies formulated by airframe manufacturers and equipment suppliers to test and implement existing HM solutions to operate under flight conditions. This highlights the need to develop HM in this field and a requirement for further research to allow this technology to be a part of routine aircraft.
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    Review of sonic boom prediction and reduction methods for next generation of supersonic aircraft
    (MDPI, 2023-10-27) Bonavolontà, Giordana; Lawson, Craig;; Riaz, Atif
    The reduction of sonic boom levels is the main challenge but also the key factor to start a new era of supersonic commercial flights. Since 1970, a FAA regulation has banned supersonic flights overland for unacceptable sonic booms at the ground, and many research studies have been carried out from that date to understand sonic boom generation, propagation and effects, both on the environment and communities. Minimization techniques have also been developed with the attempt to reduce sonic boom annoyance to acceptable levels. In the last 20 years, the advances in both knowledge and technologies, and companies and institutions’ significant investments have again raised the interest in the development of new methods and tools for the design of low boom supersonic aircraft. The exploration of unconventional configurations and exotic solutions and systems seems to be needed to effectively reduce sonic boom and allow supersonic flight everywhere. This review provides a description of all aspects of the sonic boom phenomenon related to the design of the next generation of supersonic aircraft. In particular, a critical review of the prediction and minimization methods found in the literature, aimed at identifying their strengths, limitations and gaps, is made, along with a complete overview of disruptive unconventional aircraft configurations and exotic active/passive solutions to boom level reduction. The aim of the work is to give a clear statement of state-of-the-art sonic boom prediction methods and possible reduction solutions to be explored for the design of next low-boom supersonic aircraft.
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    Rotorcraft systems modelling for twin-engine heavy helicopter
    (International Council of the Aeronautical Sciences (ICAS), 2017-03-31) Hashim, Farahani; Lawson, Craig;; Judt, David
    The projected growth in air travel over the coming decades has been extensively documented in the open literature. Most of this growth comes from fixed wing aircraft travels, and therefore much research has been reported in this aircraft category. Much less documentation on the subject is available for the rotorcraft counterpart. Nevertheless, the environmental impact of rotorcraft should not be taken lightly. This research focuses on quantifying and reducing the negative environmental impact that rotorcraft operations have. This is achieved in particular by modelling the rotorcraft airframe systems and analyzing their environmental impact at mission level. This will be achieved by investigating the concept of a more-electric rotorcraft, in realizing the 'green rotorcraft' concept aspired to in the Clean Sky project. The Rotorcraft Mission Energy Management (RMEM) model is a tool developed which represents all of the secondary power generation and user systems on a rotorcraft. The RMEM simulates the onboard helicopter systems and determines, the shaft power and engine bleed air off-take requirements of each system for prescribed sets of flight conditions. For the purpose of demonstration, three generations of rotorcraft will be presented: the current, the near-term future and the medium-term future; with each generation having different levels of technology installed. A simulation of a mission case study will be presented which analyses the total shaft power off-take of each rotorcraft as a function of mission time.
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    Simulating actuator energy consumption for trajectory optimisation
    (SAGE, 2017-06-13) Cooper, Michael; Lawson, Craig;; Zare Shahneh, Amir
    This work aims to construct a high-speed simulation tool which is used to quantify the dynamic actuator power consumption of an aircraft in flight, for use within trajectory optimisation packages. The purpose is to evaluate the energy penalties of the flight control actuation system as an aircraft manoeuvre along any arbitrary trajectory. The advantage is that the approximations include major transient properties which previous steady state techniques could not capture. The output can be used to provide feedback to a trajectory optimisation process to help it compute the aircraft level optimality of any given flight path. The tool features a six degree of freedom dynamic model of an aircraft which is combined with low frequency functional electro-mechanical actuator models in order to estimate the major transient power demands. The actuator models interact with the aircraft using an aerodynamic load estimator which generates load forces on the actuators that vary as a function of flight condition and control surface demands. A total energy control system is applied for longitudinal control and a total heading control system is implemented to manage the lateral motion. The outer loop is closed using a simple waypoint following guidance system with turn anticipation and variable turn radius control. To test the model, a simple trajectory analysis is undertaken which quantifies a heading change executed with four different turn rates. The tool shows that the actuation system requires 12.8 times more electrical energy when performing a 90° turn with a radius of 400 m compared to 1000 m. A second test is performed to verify the model’s ability to track a longer trajectory under windy conditions.
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    Tip timing techniques for turbomachinery HCF condition monitoring
    (University of Cambridge, 2002) Ivey, P. C.; Grant, K. R.; Lawson, Craig;
    High Cycle Fatigue (HCF) has been established as the major common failure mode in the US Air Force large fleet of aero-engines. Corrective measures for this failure mode in themselves deliver additional technical, managerial and cost pressures. Two responses are in place to address this problem; risk mitigation through accelerated engine development fixes and technology transition through targeted and focussed R&D studies. It is the latter that is of interests and is discussed in this paper. Aero-engine blade vibrations of sufficient amplitude cause High Cycle Fatigue, which reduces blade life. In order to observe this vibration a non-intrusive monitoring system is sought. The vibration can be detected by measuring blade tip timing since in the presence of vibration the blade timing will differ slightly from the passing time calculated from rotor speed. Work done to investigate the suitability of a commercially available capacitance probe tip clearance measurement system for application as a non-intrusive turbomachinery blade tip timing measurement device is reported. Capacitance probe results are correlated with simultaneously measure strain gauge results and the performance of the capacitance system in measuring blade vibration is analysed. The growing interest in blade high cycle fatigue within the aerospace industry, and an approach to monitoring their condition are discussed as an extension to the above study. The suggested approach is based upon the tip-timing method, using non-contact optical probes located around the engine’s casing. Two current tip-timing techniques are suggested for the purpose. The techniques are summarised, the experimental validation of both methods outlined, and the approach taken to investigate the potential use as a condition monitoring tool described. The paper is concluded with a discussion of the future use of tiptiming as a condition monitoring tool.