Browsing by Author "Hayes, David"
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Item Open Access Adopting exergy analysis for use in aerospace(Elsevier, 2017-08-05) Hayes, David; Lone, Mudassir; Whidborne, James F.; Camberos, José; Coetzee, EtienneThermodynamic analysis methods, based on an exergy metric, have been developed to improve system efficiency of traditional heat driven systems such as ground based power plants and aircraft propulsion systems. However, in more recent years interest in the topic has broadened to include applying these second law methods to the field of aerodynamics and complete aerospace vehicles. Work to date is based on highly simplified structures, but such a method could be shown to have benefit to the highly conservative and risk averse commercial aerospace sector. This review justifies how thermodynamic exergy analysis has the potential to facilitate a breakthrough in the optimization of aerospace vehicles based on a system of energy systems, through studying the exergy-based multidisciplinary design of future flight vehicles.Item Open Access Aeroelastic scaling for flexible high aspect ratio wings(AIAA, 2019-12-31) Yusuf, Sezsy; Pontillo, Alessandro; Weber, Simone; Hayes, David; Lone, MudassirThis paper provides an overview of the work conducted as part of the Cranfield BEAmReduction and Dynamic Scaling (BeaRDS ) programme, which aims to develop a methodologyfor designing, manufacturing and testing of a dynamically scaled High Aspect Ratio (HAR)Wing inside Cranfield 8’x6’ wind tunnel. The aim of this paper is to develop a methodologythat adopts scaling laws to allow experimental testing of a conceptual flexible-wing planformas part of the design process. Based on the Buckinghamπtheorem, a set of scaling lawsare determined that enable the relationship between a full-scale and sub-scale model. Thedynamically sub-scaled model is manufactured as a combination of spar, skin, and addedmass representing the stiffness, aerodynamic profile, and aeroelastic behaviour respectively.The spar was manufactured as a cross-sectional shape using Aluminium material, while theskin was manufactured using PolyJet technology. Compromises due to the manufacturingprocess are outlined and lessons learned during the development of the sub-scaled model arehighlighted.Item Open Access Exergy methods for commercial aircraft integrating the laws of thermodynamics into all disciplines of aircraft design.(2018-07) Hayes, David; Lone, Mudassir M.; Whidborne, James F.; Coetzee, EtienneAs a consequence of practicalities, work share and difficulties in designing complex aerospace systems, there has been historical segregation of sub-systems in aircraft design. This methodology has proved successful for conventional swept wing aircraft configurations, as the sub-systems are only loosely integrated with one another. This results in discipline-specific performance, loss and optimization metrics being developed at sub-system level, which are not clearly linked to the overall system performance or objective. To meet social, economic and environmental needs, the next generation of aircraft require revolutionary concepts, which tend to be far more integrated, similar to military vehicles. Thus, performance, loss and optimization metrics need to be considered at system level, in order to account for the interactions between competing engineering disciplines. This thesis advocates an alternative systems engineering approach to developing future commercial aircraft, where the universal thermodynamic metrics energy and entropy are coupled to provide a holistic performance, loss and optimization metric for all aircraft disciplines. The method known as exergy analysis has been applied in the development of propulsion systems, but is sparsely applied in other aerospace disciplines. Applying the laws of thermodynamics to all aircraft sub-systems can seem obscure, especially in mature disciplines such as aerodynamics where energy may only be considered implicitly. Along with conventional configurations, this thesis studies a conceptual highly integrated High Aspect Ratio Wing (HARW) aircraft with morphing wing-tips, where the extended wingspan improves aerodynamic performance but as a consequence the wings have greater flexibility. Morphing is not a widely proliferated technology primarily due to the conservative approach to civil aircraft design, but original equipment manufacturers also struggle to demonstrate how the morphing effectiveness on a scale model can be scaled up to a full size aircraft. This thesis shows a clear contribution to knowledge in extending the current exergy methodology by investigating flight dynamic exergy analysis, and its application to morphing technologies for large commercial aircraft, evaluating the aerodynamic and aeroelastic contribution to an aircraft’s overall exergy use. To achieve this, each node of the Collar’s triangle [27] is evaluated using the exergy metric. In the absence of an open-source code, a non-linear structural code designated the Beam Reduction (BeaR ) model, has been written to study the structural dynamics of an airframe written in MSC Nastran format within a MATLAB® / Simulink® environment. To facilitate the study of flight dynamics, a bespoke Prandtl-Glauert aerodynamics model with an exergy post-processing script has been developed. Static and dynamic aeroelastic effects were studied through a coupling of the aforementioned structure and aerodynamic exergy based models. One of the main barriers to applying exergy analysis to commercial aircraft is gaining acceptance of a novel methodology in disciplines with entrenched practices. An example being in aerodynamic design, where the force balance approach is the established analysis method, yet exergy analysis requires the engineer to consider an alternative view of the aerodynamics as a system that uses and converts energy. To counter this, the thesis shows the capability and benefits of exergy analysis over conventional analysis techniques. This is emphasised in the comparison of using exergy based methods or the Breguet Range Equation for assessing the performance benefit of morphing wing extensions, where both methods provide the same top level conclusion, but exergy provides additional insight into the system the Breguet analysis can not.Item Open Access Flexible high aspect ratio wing: Low cost experimental model and computational framework(AIAA, 2018-01-13) Pontillo, Alessandro; Hayes, David; Dussart, Gaétan X.; Lopez Matos, Guillermo E.; Carrizales, Martin A.; Yusuf, Sezsy Y.; Lone, Mohammad M.Aircraft concepts of tomorrow, such as high aspect ratio wing aircraft, are far more integrated between technical disciplines and thus require multidisciplinary design approaches. Design tools able to predict associated dynamics need to be developed if such wing concepts are to be matured for use on future transport aircraft. The Cranfield University Beam Reduction and Dynamic Scaling ( BeaRDS) Programme provides a framework that scales a conceptual full size aircraft to a cantilevered wing model of wind tunnel dimensions, such that there is similitude between the static and dynamic behaviour of the model and the full size aircraft. This process of aeroelastically scaled testing combines the technical disciplines of aerodynamics, flight mechanics and structural dynamics, to provide a means by which future concept aircraft can be de-risked and explored . Data acquisition from wind tunnel testing can then be used to validate fluid-structure interaction frameworks that model the aeroelastic effect on the flight dynamics of the aircraft. This paper provides an overview of the BeaRDS methodology, and focuses on the Phase I of the programme, being the development of a reduced Cranfield A-13 aircraft cantilevered wing, to mitigate risk associated with the manufacturing and instrumentation app roach. It is shown that a low cost acquisition system of commercial Inertial Measurement Units (IMUs) can measure the response of the wing within the desired frequency range. Issues associated with the Phase I testing are discussed, and methods are proposed for the Phase II programme that allow these problems to be resolved for a larger scale flexible wing with active control surfaces.