Cranfield Institute of Technology - PhD, EngD, MSc, MSc by research theses, (CIT)

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Browsing Cranfield Institute of Technology - PhD, EngD, MSc, MSc by research theses, (CIT) by Publisher "Cranfield University"

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    Computational design for micro fluidic devices using lattice boltzmann and heuristic optimisation algorithms
    (Cranfield University, 2010-09) D'Ammaro, Antonio; Savill, Mark A.; Kipouros, Timoleon
    The study on micro devices is gaining importance in various fields from biological to engineering. The dimensions of these devices range from millimetres (mm) to micrometres (μm) and they work within the laminar flow regime due to their low Reynolds number. Although diffusivity dictates the mixing in such conditions, this work is based on the simulation of two non reacting iso-thermal and incompressible fluids for both streams, so the mixing is governed only by turbulence. A numerical study using the Lattice Boltzmann method (LBM) is carried out in order to examine the mixing in one configuration. In the second part of the work an interface is developed between the LBM code and multi objective optimisation software in order to investigate new configurations which enhance the mixing. The objectives are to maximise the vorticity and minimise the pressure drop, which are conflicting between themselves. The tool that integrates the optimiser and the LBM code for simulating microreactor, can run on a multi level parallelisation, hence the time required for the whole simulation has been drastically reduced. A preliminary optimisation is performed on a microreactor with multi holed baffle plate. Despite small number of iterations, three totally different configurations have been found: greatest vorticity, smallest pressure drop and a compromise. The first two configurations satisfy the expectations, whereas the compromise solution presents an innovative configuration. In fact, it has a low pressure drop and a high vorticity, which is achievable by having high Reynolds number and big diameters of the holes. Hence, this tool proves to be robust and efficient in the multi objective optimisation of microreactor.
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    Design Project 1974/75 A 74 Aircraft Elevator Design.
    (Cranfield University, 1975-05) Mani Abraham, P.; Howe, D.; Tetlow, R.; Ward, R. E.
    Part 1 of this thesis contains the symmetric loading calculations and evolution of the design of elevator for the A 74 Reduced Take off and landing aircraft. Part 2 contains the analysis of final design of elevators. The aircraft is designed to the specifications of DES 7400 and satisfies the British Civil Airworthiness Requirement. A 74 project aircraft has longitudinal control from the tail plane and elevator combination. Tail plane is used for trimming and elevators for pitch controls. All control surfaces are hydraulic power operated. The tailplane uses an inverted supercritical section. The elevator is a four piece arrangement with duplicated hydraulic actuator system. It is of round nose type and the elevator hinge line is at 0.6 C. perpendicular to the aircraft centre line. As elevators are fully power operated mass balancing is not provided. Section 5 in part 1 gives the schemes considered in the design of elevator leading to the final choice of each major part. Section 6 gives the description of final design. Elevator is made of conventional built up construction using Aluminium alloy L 72 sheets and L 65 forgings. Part 2 gives the detailed stress analysis of the final design in accordance with normal aircraft design practise.
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    Gibson’s criteria: lectures and exercises for test pilots and flight test engineers
    (Cranfield University, 2014-06) Hathaway, Christopher; Lee, D.
    Empire Test Pilots’ School (ETPS) trains experienced military pilots, engineers and civilian engineers as Test Pilots and Flight Test Engineers. Over a year, ETPS broadens the experience of each student through exposure to a wide variety of aircraft in addition to increasing their depth of understanding of how aerodynamics affect the handling qualities and ultimately the mission effectiveness of aircraft. The advent of computerized flight control systems has reduced the role of the aerodynamicist to a necessary one but no longer sufficient to achieve excellent handling qualities. Complex software programming performed by a control engineer is now required to realize this goal. Consequently, second order handling qualities criteria such as the longitudinal short period natural frequency and damping ratio are no longer strictly applicable to the significantly higher order modern flight control systems. Gibson’s Criteria was developed to provide control engineers the ability to design in excellent handling qualities from the outset, rather than waiting for pilots to identify failures during testing. While ETPS students are introduced to Gibson’s Criteria as part of the graduate course, the emphasis is on exposure and not an in-depth understanding. As the expense and time to develop modern high order aircraft grows exponentially, the importance of getting the handling qualities correct from the start only becomes more acute. It would be highly beneficial for graduates of ETPS to have a comprehensive understanding of how Gibson’s Criteria is applied early in software development to ensure excellent handling qualities are designed in early and effectively. This thesis is a survey of current material on Gibson’s Criteria and existing aircraft data / handling qualities problems formatted as a series of lectures and Matlab based problems designed to be given as part of the ETPS graduate course to achieve that level of knowledge.