Optimisation of Proprotors for Performance and Noise

随着全球对更可持续航空的推动，新的电动飞机平台正在开发中。这些飞行器可能是较小规模的电池驱动的无人机，也可能与装有氢电动力总成的商用飞机一样大。人们还希望这种飞机具有垂直起降能力，作为城际飞行出租车使用。这种动力总成通常由螺旋桨驱动，但缺乏设计和验证工具来优化这些动力总成，以适应这一新角色。此外，对于商用飞机，从涡轮螺旋桨到氢电动力总成的过渡导致了气动声学研究的范围。以前，螺旋桨在这种飞机上产生的噪音是次要的，因此不被视为主要设计参数。随着人们的注意力转向在人口稠密的城市地区进行可持续的“无声”飞行，对公众的噪音干扰正成为一个重要因素。目前对螺旋桨噪声的设计研究有限，特别是在考虑垂直起降和过渡到巡航飞行的情况下。这项研究旨在通过以下目标占据这一空间：设计、建造和委托螺旋桨试验台，并与公布的数据进行比较开发螺旋桨性能和几何优化代码(Bath BEMT软件)通过将预测与水平、垂直和过渡飞行的试验台测试相关联来验证BEMT代码，将噪声因素纳入设计过程，并通过在试验台上进行带有麦克风阵列的螺旋桨声学测试来验证这些目标这些目标将导致下一代螺旋桨驱动飞机的全面且经过验证的设计工具。给定任务参数和要求，如噪声、推力、扭矩和效率，将生成最佳螺旋桨。然后，这种螺旋桨可以安装在上述类型和应用的飞机上。这项研究将特别关注低雷诺数、大迎角、垂直起降-巡航转变和失速后对螺旋桨设计的影响，因为这些仍然是应用BEMT建模时验证最少的。为这些eVTOL应用生成优化螺旋桨的能力将允许改进这些新型航空航天平台的设计，同时最大化其推进效率，并将对公众的声学干扰降至最低。成功地将高效、安静的螺旋桨安装在商用飞机上，将通过替代推进系统增加可持续航空的可行性，从而加速从化石燃料驱动的飞行过渡。

With the global drive towards more sustainable aviation, new electric aircraft platforms are being developed. These may be smaller scale battery-powered drone craft, or as large as commercial aircraft with hydrogen-electric powertrains. There is also the desire for such craft to have vertical take-off and landing capacities, for use as inter-city flying taxis. Such powertrains are most commonly driven by propellers, but there exists a lack of design and validation tools for optimising these for this new role. In addition, for commercial aircraft, the transition from turboprop to hydrogen-electric powertrains results in the scope for aeroacoustic research. Previously, the noise generated by a propeller on such an aircraft was secondary, and thus not considered as a primary design parameter. With the shift in focus towards sustainable, "silent" flight in dense urban areas, the noise disturbance to the public is becoming a significant factor. Limited research exists in the design of a propeller for noise, particularly when considering VTOL, and the transition to cruise flight. This research aims to occupy this space, through the following objectives: Design, build, and commission a propeller test rig and compare against published data Develop a propeller performance and geometry optimisation code (Bath BEMT software) Validate the BEMT code by correlating its predictions to rig tests in horizontal, vertical, and transitional flight Implement noise considerations into the design process, and validate these through acoustic testing of propellers on the rig with microphone arraysThese objectives will result in a comprehensive and validated design tool for the next generation of propeller-driven aircraft. Given mission parameters and requirements, such as for noise, thrust, torque, and efficiency, an optimal propeller will be generated. Such propellers could then be implemented onto aircraft of the types and applications listed above. This research will focus particularly on the low Reynolds number, high angle-of-attack, VTOL-cruise transition, and post-stall influences on propeller design, as these remain the least validated when applying BEMT modelling.The ability to generate optimised propellers for these eVTOL applications will permit the advancement of the design of these novel aerospace platforms, while maximising their propulsive efficiencies, and minimising the acoustic annoyance to the public. The successful implementation of high-efficiency, quiet propellers onto commercial aircraft will accelerate the transition away from fossil-fuel powered flight by increasing the feasibility of sustainable aviation through alternative propulsive systems.