Adverse Effects of Using Laser Diagnostics in High-Speed Compressible Flows

在高速可压缩流中使用激光诊断的不利影响

• 批准号: RGPIN-2018-04753
• 负责人: Johansen, Craig
• 金额: $ 4.01万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=654706
• 关键词: Adverse; Effects; Using; Laser; Diagnostics

This proposal focuses on studying the adverse effects that laser diagnostics can have on high-speed, compressible flows. Two broad diagnostic areas are targeted: particle-based and spectroscopic methods. It is expected that particle-gas interactions, which occur with particle-image velocimetry (PIV), can lead to rapid exchanges of momentum and energy in a high-speed flow and alter major gas-dynamic features, such as shock waves. It is also expected that gas seeding associated with planar laser-induced fluorescence (PLIF) and dissociation associated with femtosecond laser electronic excitation and tagging (FLEET) can also alter the separation in the near wake of a re-entry capsule flow. While gas-particle and gas-laser interactions can adversely alter the flow and lead to measurement uncertainty, these mechanisms will be exploited in this program to improve aerospace systems including intakes, thermal protection, and flow-control technologies. ******Using a shock tunnel, two canonical cases will be analyzed to assess any adverse diagnostic effects: the under-expanded jet and circular cylinder. Artificial flow responses will be monitored as inputs such as particle loading level, seed gas flow rates, and laser energy levels are varied. It is hypothesized that there are conditions where particle cooling has a larger effect than particle drag on displacing the Mach disk location in an under-expanded jet. It is also hypothesized that gas seeding and laser energy deposition near the lip-shock boundary-layer interaction region will perturb the free shear layer in the near wake of the circular cylinder and move the point of separation region (affecting base pressure and heating loads). Through an on-going 7-yr collaboration, Mach 6 and Mach 10 experiments using FLEET and PLIF will be performed at the NASA Langley on the circular cylinder case. Results will be compared to the impulse facility measurements at the University of Calgary. Computational flow imaging (CFI) will be used to both predict and correct for the unwanted gas-particle and gas-laser interactions that are expected to occur. CFI and experiments will be used to assess how cooled particles can be used to improve supersonic intake performance and how gas seeding and laser energy deposition can be used for flow control on the aft-bodies of re-entry capsules. ******This program is expected to have a large impact on extending more conventional laser diagnostics to high Mach number flows as well as to quantify the limitations of some newer diagnostics in general. The canonical problems chosen are relevant to rocket propulsion, hypersonic air-breathing propulsion, re-entry aerodynamics, missiles, and high-speed ballistics. Training of highly qualified personnel (HQP) in the area of laser diagnostics, numerical simulation, wind tunnel experiments, and aerospace technologies is a valuable output to grow Canada's knowledge-based economy.

该提案的重点是研究激光诊断可能对高速可压缩流产生的不利影响。两个广泛的诊断领域的目标：基于粒子和光谱的方法。粒子图像测速技术（PIV）可以使粒子与气体发生相互作用，从而导致高速流动中动量和能量的快速交换，并改变主要的气体动力学特征，如冲击波。还可以预期，与平面激光诱导荧光（PLIF）和与飞秒激光电子激发和标记（FLEET）相关的解离相关的气体播种也可以改变再入舱流近尾流中的分离。虽然气体-颗粒和气体-激光相互作用可能会对流动产生不利影响，并导致测量不确定性，但这些机制将在该计划中被利用，以改善航空航天系统，包括进气道，热保护和流量控制技术。 ** 使用冲击风洞，将分析两个典型案例以评估任何不良诊断影响：膨胀不足的射流和圆柱体。随着输入（例如颗粒负载水平、种子气体流速和激光能量水平）的变化，将监测人工流响应。假设在某些情况下，颗粒冷却比颗粒阻力对欠膨胀射流中马赫盘位置的位移有更大的影响。还假设在唇激波边界层相互作用区域附近的气体播种和激光能量沉积将扰动圆柱近尾流中的自由剪切层并移动分离区域的点（影响底压和热载荷）。通过一项持续7年的合作，将在NASA兰利中心对圆柱体进行使用FLEET和PLIF的马赫数6和马赫数10的实验。结果将与卡尔加里大学的脉冲设施测量结果进行比较。计算流成像（CFI）将用于预测和校正预期会发生的不必要的气体-颗粒和气体-激光相互作用。CFI和实验将用于评估如何使用冷却颗粒来改善超音速进气道性能，以及如何使用气体播种和激光能量沉积来控制再入舱后体的流动。** 预计这个计划将对把较传统的激光诊断扩展到高马赫数流以及对某些较新的诊断的一般局限性进行量化产生很大的影响。所选的规范问题与火箭推进、高超音速吸气式推进、再入空气动力学、导弹和高速弹道学有关。对激光诊断、数值模拟、风洞实验和航空航天技术领域的高素质人员进行培训，是促进加拿大知识经济发展的宝贵成果。