Browsing by Author "Kyprianidis, Konstantinos G."
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Item Open Access Multi-disciplinary conceptual design of future jet engine systems(Cranfield University, 2010-04) Kyprianidis, Konstantinos G.; Ogaji, S.; Singh, R.This thesis describes various aspects of the development of a multi-disciplinary aero engine conceptual design tool, TERA2020 (Techno-economic, Environmental and Risk Assessment for 2020), based on an explicit algorithm that considers: engine performance, engine aerodynamic and mechanical design, aircraft design and performance, emissions prediction and environmental impact, engine and airframe noise, and production, maintenance and direct operating costs. As part of this research e ort, a newly-derived semi-empirical NOx correlation for modern rich-burn single-annular combustors is proposed. The development of a numerical methods library is also presented, including an improved gradientbased algorithm for solving non-linear equation systems. Common assumptions made in thermo- uid modelling for gas turbines and their e ect on caloric properties are investigated, while the impact of uncertainties on performance calculations and emissions predictions at aircraft system level is assessed. Furthermore, accuracy limitations in assessing novel engine core concepts as imposed by current practice in thermo- uid modelling are identi ed. The TERA2020 tool is used for quantifying the potential bene ts from novel technologies for three low pressure spool turbofan architectures. The impact of failing to deliver speci c component technologies is quanti ed, in terms of power plant noise and CO2 emissions. To address the need for higher engine thermal e ciency, TERA2020 is again utilised; bene ts from the potential introduction of heat-exchanged cores in future aero engine designs are explored and a discussion on the main drivers that could support such initiatives is presented. Finally, an intercooled core and conventional core turbofan engine optimisation procedure using TERA2020 is presented. A back-to-back comparison between the two engine con gurations is performed and fuel optimal designs for 2020 are proposed. Whilst the detailed publications and the work carried out by the author, in a collaborative e ort with other project partners, is presented in the main body of this thesis, it is important to note that this work is supported by 20 conference and journal papers.Item Open Access On gas turbine conceptual design.(2019-01) Kyprianidis, Konstantinos G.; Sethi, VishalThe thesis begins with a review of the evolution of the industry's vision for the aero-engine design of the future. Appropriate research questions are set that can influence how this vision may further evolve in the years to come. Design constraints, material technology, customer requirements, noise and emissions legislation, technology risk and economic considerations and their effect on optimal concept selection are discussed in detail. Different aspects of the pedagogy of gas turbine conceptual design as well as information on the Swedish and Brazilian educational systems are also presented. A multi-disciplinary aero-engine conceptual design tool is utilised for assessing engine/aircraft environmental performance. The tool considers a variety of disciplines that span conceptual design including: engine performance, engine aero-dynamic and mechanical design, aircraft design and performance, emissions prediction and environmental impact, engine and airframe noise, and production, maintenance and direct operating costs. With respect to addressing the research questions set, several novel engine cycles and technologies - currently under research - are identified. It is shown that there is great potential to reduce fuel consumption for the different concepts identified, and consequently decrease the CO₂ emissions. Furthermore, this can be achieved with sufficient margin from the NOᵪ certification limits set by International Civil Aviation Organisation, and in line with the medium-term and long-term goals set through it's Committee on Aviation Environmental Protection. The option of an intercooled-core geared-fan aero-engine for long-haul applications is assessed by means of a detailed design space exploration. An attempt is made to identify the fuel burn optimal values for a set of engine design parameters by varying them all simultaneously, as well as in isolation. Different fuel optimal designs are developed based on different sets of assumptions. Evidence is provided that higher overall pressure ratio intercooled engine cycles become more attractive in aircraft applications that require larger engine sizes. The trade-off between the ever-increasing energy efficiency of modern aero-engines and their NOᵪ performance is assessed. Improving engine thermal efficiency has a detrimental effect on NOᵪemissions for traditional combustors, both at high altitude and particularly at sea-level conditions. Lean-combustion technology does not demonstrate such behaviour and can therefore help decouple NOᵪ emissions performance from engine thermal efficiency. If we are to reduce the contribution of aviation to global warming, however, future certification legislation may need to become more stringent and comprehensive, i.e., cover high altitude conditions. By doing so we can help unlock the competitive advantage of lean burn technology in relation to cruise NOᵪ and mission performance. Finally, some insight is provided on the potential benefits to be tapped from a transition from the traditional deterministic approach for system analysis to a stochastic (robust design) approach for economic decision-making under uncertainty. A basic methodology is outlined and applied on a specific conceptual design case for a conventional turbofan engine. The sensitivity of an optimal engine design obtained deterministically to real-life uncertainties is found to be far from negligible. The considerable impact of production scatter, measurement uncertainties as well as component performance deterioration, on engine performance must be catered for; this includes taking into consideration control system design aspects. A fast analytical approach is shown to be sufficiently accurate for the conceptual design process, particularly for estimating key performance parameters. These relate to type-test certification and performance retention guarantees including preliminary estimates of engine production margins. Lessons learned are presented from: (i) the integration of different elements of conceptual design in a new BSc course and an existing traditional MSc course on gas turbine technology, (ii) the development of an intensive course on gas turbine multi-disciplinary conceptual design. The results from the use of problem-based learning are very encouraging, in terms of enhancing student learning and developing engineering skills.