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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=690506
• 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对高速可压缩流的不利影响。针对两个广泛的诊断领域：基于粒子的方法和光谱方法。预计粒子图像测速 (PIV) 中发生的粒子-气体相互作用可以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，例如冲击波。还预计与平面激光诱导荧光（PLIF）相关的气体播种和与飞秒激光电子激发和标记（FLEET）相关的解离也可以改变返回胶囊流的近尾流中的分离。虽然气体-粒子和气体-激光相互作用会对流量产生不利影响并导致测量不确定性，但该计划将利用这些机制来改进航空航天系统，包括进气口、热保护和流量控制技术。 ******使用冲击隧道，将分析两个典型案例以评估任何不利的诊断效果：膨胀不足的射流和圆柱体。随着粒子负载水平、种子气体流速和激光能量水平等输入的变化，人工流动响应将受到监控。据推测，在某些情况下，颗粒冷却对移动欠膨胀射流中马赫盘位置的影响比颗粒阻力更大。还假设唇激波边界层相互作用区域附近的气体引晶和激光能量沉积将扰动圆柱体近尾流中的自由剪切层并移动分离区域的点（影响基础压力和热载荷）。通过持续 7 年的合作，使用 FLEET 和 PLIF 的马赫数 6 和马赫数 10 的实验将在 NASA 兰利的圆柱体案例上进行。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）将用于预测和纠正预期发生的不需要的气体-粒子和气体-激光相互作用。 CFI 和实验将用于评估如何使用冷却粒子来提高超音速进气性能，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量。 ******该计划预计将对将更传统的激光诊断扩展到高马赫数流以及量化一些较新诊断的局限性产生重大影响。所选择的典型问题与火箭推进、高超音速吸气推进、再入空气动力学、导弹和高速弹道学相关。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才 (HQP) 培训是发展加拿大知识型经济的宝贵成果。