Browsing by Author "Jackson, Anthony J. B."

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    CFD investigation of a core-mounted-target-type thrust reverser, Part 1: reverser stowed configuration
    (ASME, 2017-12-25) Mahmood, Tashfeen; Jackson, Anthony J. B.; Sethi, Vishal; Khanal, Bidur; Ali, Fakhre
    During the second half of the 90's, NASA performed experimental investigations on six novel Thrust Reverser designs; Core Mounted Target Type Thrust Reverser (CMTTTR) design is one of them. To assess the CMTTTR efficiency and performance, NASA conducted several wind tunnel tests at Sea Level Static conditions. The results from these experiments are used in this paper series to validate the CFD results. This paper is part one of the three-part series; Part 1 and 2 discusses the CMTTTR in stowed and deployed configurations, all analysis in the first two papers are performed at SLS conditions. Part3 discusses the CMTTTR in the forward flight condition. The key objectives of this paper are: first, to perform the 3D CFD analysis of the reverser in stowed configuration; all analyses are performed at SLS condition. The second objective is to validate the acquired CFD results against the experimental data provided by NASA[1]. The third objective is to verify the fan and overall engine net thrust values acquired from the aforementioned CFD analyses against those derived based on 1-D engine performance simulations. The fourth and final objective is to examine and discuss the overall flow physics associated with the CMTTTR under stowed configuration. To support the successful implementation of the overall investigation, full-scale 3DCAD models are created, representing a fully integrated GE90 engine, B777 wing, and pylon configuration. Overall a good agreement is found between the CFD and test results; the difference between the two was less than 5%.
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    CFD investigation of a core-mounted-target-type thrust reverser, Part 2: reverser deployed configuration
    (ASME, 2017-12-25) Mahmood, Tashfeen; Jackson, Anthony J. B.; Sethi, Vishal; Khanal, Bidur; Fakhre, Ali
    CMTTTR design was proposed by NASA in the second half of the 90's. NASA carried out several experiments at static conditions, and their acquired results suggested that the performance characteristics of the CMTTTR design falls short to comply with the mandatory TR performance criteria, and were therefore regarded as an infeasible design. However, the authors of this paper believe that the results presented by NASA for CMTTTR design require further exploration to facilitate the complete understanding of its true performance potential. This Part2 paper is a continuation from Part1and presents a comprehensive three-dimensional (CFD) analyses of the CMTTTR in deployed configuration; the analyses at forward flight conditions will be covered in Part 3. The key objectives of this paper are: first, to validate the acquired CFD results with the experimental data provided by NASA: this is achieved by measuring the static pressure values on various surfaces of the deployed CMTTTR model. The second objective is to estimate the performance characteristics of the CMTTTR design and corroborate the results with experimental data. The third objective is to estimate the Pressure Thrust (i.e. axial thrust generated due to the pressure difference across various reverser surfaces) and discuss its significance for formulating the performance of any thrust reverser design. The fourth objective is to investigate the influence of kicker plate installation on overall TR performance. The fifth and final objective is to examine and discuss the overall flow physics associated with the thrust reverser under deployed configuration.
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    Optimisation of aero and industrial gas turbine design for the environment
    (Cranfield University, 2009-02) Jackson, Anthony J. B.; Pilidis, Pericles
    The aspects of gas turbine design that are explored herein are focussed on reduction or elimination of carbon dioxide (CO2) emissions and reduction of noise. There are 3 separate but related investigations. 1. Aero gas turbine engine thermodynamic cycles for subsonic transport aircraft are explored to optimise performance (thus reducing CO2 emissions) and to minimise noise; particular attention is paid to choices of fan pressure ratio, bypass ratio, installation configuration and fan design. Turbofans with long and short cowls are explored, as are propfans of various bypass ratios. The performance and noise comparisons of the engines are made using consistent technology standards; this approach is not apparently available in the literature. It is shown that relative to present day engines, useful improvements in Direct Operating Cost (DOC), fuel burn and noise are possible. It is shown, not surprisingly, that the optimum installed engine cycles for performance and noise are different. 2. The performance effects of using hydrogen fuel in “conventional” aero gas turbine engines are discussed. Also, some novel un-conventional hydrogen fuelled aero gas turbine cycles are examined. Hydrogen fuelled engines create no emissions of CO2; however, this environmental benefit is partly offset by the increased water in the engine contrails. It is shown that “conventional” engines benefit from using hydrogen fuel, measured by the thrust obtained for a given fuel energy input rate. The novel un-conventional configurations that are examined offer useful performance benefits, including significant power increases, by suitable use of the cold “sink” and high pressure of the liquid hydrogen fuel. 3. Two ways of eliminating CO2 emissions from industrial gas turbines are examined. The first is by use of hydrogen-rich fuel. There are performance gains, as with the aero engines; however in the industrial cases, the hydrogen is sometimes produced in such a way that it is mixed with substantial amounts of nitrogen, which significantly influences the results. The second is the use of CO2 in the working fluid for partially-closed and closed cycle arrangements. This permits easy sequestration of excess CO2 without the use of the large separating equipment that is necessary for extracting CO2 from the exhausts of standard open cycle plants breathing air. The changes required to a standard gas turbine to allow it to use CO2 as its working fluid are explored in some detail; this is not clearly addressed in the literature. It is shown that the turbines - the most expensive part of the gas turbine - can be operated satisfactorily but changes are sometimes required to the compressors.