School of Aerospace, Transport and Manufacturing (SATM)

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Browsing School of Aerospace, Transport and Manufacturing (SATM) by Course name "MSc by Research in Aerospace"

Now showing 1 - 7 of 7
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    Development of tail rotor power analysis model with feasibility study of electrical tail rotor.
    (2016-09) Subramanian, Nithya; Lawson, Craig
    In recent years, there has been significant work undertaken by the aviation industry to increase the overall rotorcraft performance, and eventually, eliminate leak prone hydraulic fluids and to reduce CO₂ emissions. Even though a mechanical-gearbox-driven tail rotor has been extensively used in several applications, it comes at the expense of high life cost of the gearbox and shaft gear mechanism. This thesis concentrates on the developing a model to analyse the power requirement for the tail rotor drive and feasibility investigation of an electrical tail rotor to substitute the shaft geared system and the conventional tail rotor power transmission gearbox. A case study is conducted on the Sikosky UH-60A rotorcraft to assess the conventional tail rotor power requirement and Electrical systems. A mathematical model based on Rankine Froude’s momentum theory is created to analyse the power required to drive the anti-torque system, which could be adapted to any conventional drive train (with the main rotor and a tail rotor) rotorcraft. A mission profile and trajectory are created and implemented into Excel based mathematical model. The challenges in implementing electrical drivetrain (electrical generation, energy conversion and electric transmission) are briefly discussed in this thesis. Electrical load analysis database is generated to find the electrical load of the generator for the entire flight phases and utilised to up-scaled the generator to compensate the new load from Electrical tail rotor. The electrical powertrain system is designed with a Brushless DC motor attached to the tail rotor and the generator and the battery for redundancy purposes. The research thesis develops an understanding of current electric motor and battery technology to create a novel design of electric tail drive that increases the reliability of the helicopter system.
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    Differential flatness based flight control of tilt-rotor VTOL aircraft
    (Cranfield University, 2021-11) Joseph, Emmanuel Biju; Whidborne, James F.; Chen, Lejun
    Urban Air Mobility (UAM) is identified as the future of mobility, and several airframes are being trialled to fit air transport within modern cities. Speed and efficiency are the primary requirements deliberated for UAM Vertical Take-off and Landing (VTOL) aircraft, and configurations incorporating tilt-rotors and tilt-wings have been identified as viable solutions. For quadrotors and robotics, control techniques leveraging the differentially flat property of system dynamics have achieved significantly improved tracking performance and motivated the application of this control technique for VTOL aircraft. This study proposes a novel control architecture based on the differential flatness property of aircraft kinematics, to improve controller performance for autonomous flight. A conceptual validation of the proposed technique was implemented on a Planar VTOL (PVTOL) model as a precursor to the research. Consequently, an architecture for implementing the concept in tilt-rotor VTOL aircraft (Aston Martin Vision Volante) was devised, implemented, and tested. The control architecture achieved the speculated performance improvements and lays foundation for further research and development into the proposed control technique.
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    Evaluating gas turbine fouling degradation and impact of washing on engine performance.
    (2017-11) Lewis, Andy; Igie, Uyioghosa
    Fouling of the compressor of a gas turbine is one of the major contributors to its performance degradation, not only in terms of a reduction in the potential power output revenue and increased fuel costs but also raising the operating temperatures to levels that will have an impact on the servicing intervals and costs. In view of the current economic climate and with the ever-increasing pressure on governments to reduce emissions that contribute to global warming, the need to operate power generating gas turbines in the most efficient way possible is becoming more important. The aim of this study is to demonstrate that using a single compressor dual high-pressure washing system, on multiple gas turbines and a combination of a strict on-line compressor washing regime it is possible not only reduce the rate of compressor degradation, that will enable the period between off-line washes to be extended but also maintain a higher rate of power output throughout this period. Additional benefits will include better fuel efficiency which will lead to a lowering of emissions and the added flexibility of the overall plant operation by reducing the service interventions and shutdowns for off-line washes to the minimum. This study utilises the readily available data from the gas turbine control system to understand how the performance is affected by compressor fouling over time. Once corrected to remove the variations caused by changes in the ambient conditions, the performance trend of the data can be examined in 2 ways. The comparison of the recorded degradation against the gas turbine’s own historic figures and secondly against the relative performances of adjacent machines over similar time periods. The data gathered, from 4 gas turbines, over the 3 years 8 months recording period, provided the opportunity to select 'like for like' starting points in the various life cycles. This enabled direct comparisons of the results, between the various gas turbines that had operated with different compressor washing regimes. These comparisons demonstrated that maintaining an effective on-line compressor washing regime allows for greater potential revenue from exported power; whilst at the same time being more fuel efficient and lowering operating temperatures.
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    Green hydrogen revolution in aviation: requirements and possibilities
    (Cranfield University, 2023-05) Janjua, Shahzada Sulman; Nalianda, Devaiah; Pilidis, Pericles
    This work investigates the case for sustainable aviation for the Asia Pacific region and focusses on Hong Kong. Hong Kong presently generates 50% of its energy from coal. The aim is to remove carbon from aviation fuels for Hong Kong and replace it with green hydrogen. This is a viable choice of sustainable aviation fuel but switching it from kerosene would require the overcoming of some challenges. This thesis comprises of three parts: firstly, the modelling and simulation of the Trent-XWB-97 jet engine as a baseline combusting Jet-A fuel. Its aircraft performance is then compared to a cryogenically fuelled green hydrogen engine. Secondly, the reference engine is then fitted with an intercooler with the gain of aircraft performance benefits in mind as well as to utilise it as a heat exchanger to vapourise the liquid hydrogen and thirdly, large-scale green hydrogen production using renewables is envisaged as part of a Green Hydrogen Hub network encompassing a green hydrogen logistical supply chain paving the way for a future aviation hydrogen micro-economy. It was discovered that relative to the Jet-A fuelled engine, the engine with a constant net thrust for ODP (Take-Off) and DP (Cruise) conditions decreased the ESFC for both baseline and intercooled engines. For the reference case at ODP this drop in ESFC was (1.71%) and (1.3%) for the intercooled scenario. There was also an accompanying decrease in TET; for the baseline engine this was 47K and for the intercooled engine this was 50K. The addition of the intercooler achieved the greater aircraft thrust requirement of 448kN and also vapourised the cryogenic hydrogen to high enough temperatures. These were calculated to be 536K and 296K for the ODP and DP respectively. The results showed that the baseline engine carried the greatest payload of 31866 kg with a block fuel burn of 36267 kg and a flight duration of 11.83 hours. The intercooled engine yielded a maximum carried payload of 27184 kg and the block fuel burn was 43349 kg and a flight time of 11.97 hours. The study also discovered that the 43.4 tonnes of green hydrogen can be generated in Hong Kong using wind and solar power and that its usage reduced the civil aviation carbon footprint of Hong Kong by 11.6%.
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    Implications of military aircraft’s mission optimal performance on gas turbine engine life expectancy
    (Cranfield University, 2023-08) Lazarou, Georgios; Nikolaidis, Theoklis; Devaiah, Nalianda
    Gas turbine engines have a crucial role in evaluating military aircraft performance. Operating in a range of missions and environmental conditions, they are subjected to an excessively demanding usage often reaching their operating limits. The impact prediction on engine components degradation of this adverse usage requires a multi-disciplinary approach to best capture its effects. This master thesis investigates the implications of optimal mission performance on the degradation of military gas turbine engines. The research focuses on the degradation of first stage of the high-pressure turbine caused by the failure mechanisms of creep, low cycle fatigue and high cycle fatigue, each acting independently on the turbine blades. By exploring the implications of mission performance on engine degradation, this study provides valuable insights for optimizing mission execution strategies and improving operational efficiency in military aviation. Through a comprehensive analysis, several key findings have been identified. It was observed that as the turbine entry temperature (TET) decreases, the stresses on the turbine blade have a disproportionately greater effect on the overall damage. This suggests that maintaining optimal TET levels is crucial for mitigating engine degradation, as an increase of 0.005% in blade temperature can lead to 40% more thrust, 100% more fuel consumption but can reduce life by 18% in Creep, 15% in LCF and 14% in HCF. In addition, the study reveals that the use of afterburner though having similar thermo-mechanical stresses upon the blades with the maximum dry setting, the extensive usage in a mission can significantly impact the life consumption. A mission with 40% less overall duration can present an up to 40% reduced life expectancy. Lastly, the investigation highlights the significant differences in life consumption during several optimal climb paths. A time optimized profile is found to be the most damage inflicting having 3 times less lifespan than noise and IR optimized paths. A life expectancy of only 80 flight hours is predicted for the usage applied on this profile resulting from the impact of low cycle fatigue contribution. This research contributes to the field of military-related costs by shedding light on the operational availability of gas turbine engines.
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    Phase-Based Motion Magnification in outdoor conditions: Robustness and Natural Frequency extraction
    (Cranfield University, 2021-12) El Sayah, Thierry; Petrunin, Ivan; Zanotti Fragonara, Luca
    In this study, Phase-Based Motion Magnification is combined with 2D Point Tracking to enhance data extraction under noisy outdoor conditions. The aim is to investigate whether the use of Phase Based Motion Magnification along with 2D PT can increase accuracy of frequencies extracted in robust conditions. The study presents three experiments: a fixed wing on a shaker machine, a light pole and a building. Frequencies are extracted in all three experiments and compared against previous research and finite element analysis. Finally, the study touches on ways to automate the suggested procedure.
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    Unmanned aerial vehicles as an efficient platform to enable agriculture's digital future
    (Cranfield University, 2023-05) Mwesigwa, Grace Elisha; Zolotas, Argyrios; Ignatyev, Dmitry I.
    The potential for Unmanned Aerial Vehicles to revolutionise agriculture, particularly small-scale farms, is enormous. Today, most agriculture UAVs are bulky, expensive, and primarily designed for heavy-lift applications, making them unaffordable for most small-scale farmers. Despite the availability of smaller UAVs, they were not designed for agricultural purposes, and have limited endurance. This project presents an innovative solution that involves integration of cylindrical Li-ion cells into the multirotor’s airframe structure, thereby cost- effectively enhancing endurance. Through the proposed engineering design approach, a prototype UAV is built and tested, demonstrating a significant endurance improvement over similarly sized vehicles powered by LiPo batteries. This design presents a budget friendly solution that could enable small-scale farmers to take advantage of affordable UAV technology.