Experimental Performance Characterisation and Measurement of Unstart Force on a Scramjet Intake across the Operational Envelope

超燃冲压发动机整个运行范围内进气口的启动力的实验性能表征和测量

• 批准号: 2887199
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2887199
• 关键词: Experimental; Performance; Characterisation; Measurement; Unstart

This project falls within the EPSRC Fluid dynamics and aerodynamics research area.IntroductionHypersonic vehicles travelling at over Mach 5 are in development for access to space, civil transportation, and defence purposes. To increase mission capability, air-breathing engines are favoured over rocket-based systems as they do not carry any oxidiser. For Mach 5 and over, the only viable systems are Rotary Detonation Engines (RDEs) or Supersonic Combustion Ramjets (SCRamjets). These both rely upon supersonic intake performances to compress the incoming air with minimal losses. Most intakes are designed assuming steady-state operation at a single design point yet are expected to operate over a range of flight conditions and attitudes. Transient variations adversely affect the overall performance of the intake, which can result in either engine flame out or unstart. During the development of the Lockheed SR-71 'Blackbird' aircraft, the unstart of a single engine would produce a significant yawing moment that in some instances caused the loss of the vehicle. There has been significant academic investigation with the goal of developing predictive control strategies to mitigate or prevent unstart. However, there is limited experimental data on the magnitude of force generated during unstart for scramjet inlets. It remains an open research question as to whether the forces generated are sufficient to cause loss of vehicle or adjacent-engine failure in multi-engine configurations. Project AimThe primary aim of the proposed DPhil project is to experimentally investigate the forces imparted to a vehicle during the un-start of a scramjet intake over a range of conditions. Additionally, the project will explore the influence of vehicle attitude on intake performance and differences arising between low and high-enthalpy testing.MethodologyThis study will be primarily experimental, using the Oxford High-Density Tunnel (HDT) for low-enthalpy tests and the University of Queensland reflected shock tunnel facility X3R for high-enthalpy tests. Additionally, the project will use a device called MassCap, which is a novel mass flow measurement and mechanical back-pressurisation device developed at Oxford specifically for high-speed intake testing in short-duration facilities.The bulk of the first year will be dedicated to the design of an intake. During the second year, the experimental intake model will be manufactured, and experimentally characterised in the HDT. This facility will be operated in PALM mode (a mode with extended test times) to enable the start/un-start cycle to be investigated. In the third year of the DPhil, experiments using the same model will be undertaken in the University of Queensland shock tunnel facility at flight enthalpy conditions. In this way, changes in the inlet performance due to high enthalpy effects may be examined, providing a better assessment of the performance in flight.The inlet performance will be characterised throughout the flight envelope. Measurement of the axial force induced during inlet unstart will be unique and offer insight into the impact on the overall vehicle. The change in performance with attitude, sensitivity of the intake to unstart and self-starting capability will also be investigated. High-speed Schlieren videography will be used to examine the external shock structure during starting/un-starting and the use of pressure-sensitive paint and infrared thermography to provide an improved spatial resolution of the surface pressure and heat flux (respectively) will be explored. Throughout the project, the student will interact with other student and staff members within the Oxford hypersonics groups as well as external academic, government, and industry partners, such as at the University of Queensland Centre for Hypersonics.

该项目属于EPSRC流体动力学和空气动力学研究领域的福尔斯。IntroductionHypersonic vehicles行驶在超过5马赫的发展进入太空，民用运输和国防目的。为了提高使命能力，吸气式发动机比火箭发动机更受青睐，因为它们不携带任何氧化剂。对于马赫数5及以上的飞行器，唯一可行的系统是旋转爆震发动机（RDE）或超音速燃烧冲压发动机（SCRamjets）。这些都依赖于超音速进气性能，以最小的损失压缩进入的空气。大多数进气道的设计都是假定在一个设计点上的稳态工作，但期望在一系列飞行条件和姿态下工作。瞬态变化会对进气道的整体性能产生不利影响，这可能导致发动机熄火或无法启动。在洛克希德SR-71“黑鸟”飞机的研制过程中，单个发动机的不起动会产生一个显著的偏航力矩，在某些情况下会导致飞行器的损失。有显着的学术研究的目标是发展预测控制策略，以减轻或防止不启动。然而，在超燃冲压发动机进气道未起动过程中产生的力的大小的实验数据有限。在多发动机布局中，所产生的力是否足以引起飞行器损失或相邻发动机故障，这仍然是一个开放的研究问题。DPhil项目的主要目的是实验研究在一系列条件下超燃冲压发动机进气道未启动期间施加到飞行器上的力。此外，该项目将探讨进气性能和低，高焓testing.MethodologyThis研究之间产生的差异车辆的态度的影响将主要是实验性的，使用牛津高密度隧道（HDT）的低焓测试和昆士兰州大学反射激波风洞设施X3 R的高焓测试。此外，该项目将使用一种名为MassCap的设备，这是一种由牛津大学开发的新型质量流量测量和机械背压设备，专门用于短期设施中的高速进气测试。第二年，将制造实验进气模型，并在HDT中进行实验表征。该设施将在PALM模式（一种延长试验时间的模式）下运行，以研究启动/不启动循环。在DPhil的第三年，将在昆士兰州大学激波风洞设施中进行飞行焓条件下使用相同模型的实验。通过这种方式，可以检查由于高焓效应引起的进气道性能的变化，从而更好地评估飞行中的性能。进气道性能将在整个飞行包线内得到表征。在进气道未启动过程中引起的轴向力的测量将是唯一的，并提供对整个车辆的影响的洞察力。还将研究性能随姿态的变化、进气口对不起动的敏感性和自起动能力。高速纹影摄像将用于检查启动/非启动过程中的外部激波结构，并将探索使用压敏涂料和红外热成像技术来提高表面压力和热通量的空间分辨率。在整个项目中，学生将与牛津大学高超音速小组的其他学生和工作人员以及外部学术，政府和行业合作伙伴进行互动，例如昆士兰州大学高超音速中心。