ERI: Experimental Investigation of Compressibility Effects on Turbulent Kinetic Energy Production in Supersonic Flows

ERI：压缩性对超音速流中湍动能产生的影响的实验研究

• 批准号: 2347416
• 负责人: Davide Vigano
• 金额: $ 20万
• 依托单位: Missouri University of Science and Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-03-15 至 2026-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2347416&HistoricalAwards=false
• 关键词: ERI; Experimental; Investigation; Compressibility; Effects

Hypersonic flight offers the potential to revolutionize global travel and space exploration. A crucial technology for making this a reality is the development of efficient supersonic combustors for air-breathing hypersonic engines. These combustors differ from traditional ones in their extremely short residence times, typically around 1 millisecond. In such a short time, the fuel must be injected, vaporized (for liquid fuels), dispersed, and mixed to the molecular level with the incoming air before combustion can occur. Turbulence, which aids dispersion and mixing, is vital in this process. However, understanding how compressibility affects turbulence production is still incomplete, slowing down hypersonic flight development. This project aims to investigate compressibility effects on turbulence by directly measuring turbulence in the Mach 3 wind tunnel at Missouri University of Science and Technology. As turbulence plays a key role in the mixing process, understanding its production and how it is affected by compressibility would facilitate a better understanding of the mixing process in supersonic flows and the design of supersonic combustors.While turbulence production in supersonic flows has been recently investigated, compressibility effects – particularly on density fluctuations – have been largely neglected in non-wall-bounded flows such as jets and shear, which are relevant for mixing applications. Recent research indicates that even for the relatively low supersonic Mach number of a scramjet combustor (30-40% of the flight Mach), compressibility effects on turbulence production can be comparable to incompressible turbulence production. This analysis, based on theoretical arguments and limited experimental/numerical data from the available literature, indicates that the Strong Reynolds Analogy (a correlation between velocity and density fluctuations), initially developed for boundary layers, is also valid for unbounded supersonic mixing flows. This project proposes to experimentally verify the validity of the Strong Reynolds Analogy in a supersonic mixing unbounded flow by directly measuring density and velocity fluctuations utilizing two-point Focused Laser Differential Interferometry (2-FLDI). 2-FLDI is a proven low-cost technique that allows high-frequency, simultaneous, non-intrusive measurements of density and velocity fluctuations. The flow will consist of a simple planar jet from a pylon injector in a Mach 3 free stream. This work will also support STEM outreach through the development of a summer camp, and workforce development in hypersonics by supporting both graduate and undergraduate students. Findings from this work will also be incorporated into a graduate class on turbulent flows.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Hypersonic飞行提供了彻底改变全球旅行和太空探索的潜力。使这一现实的关键技术是开发用于空气呼吸高超声发动机的有效超音速战斗人员。这些战斗在极短的停留时间与传统战斗机不同，通常约为1毫秒。在如此短的时间内，必须在可能发生混合之前将燃料注入，蒸发（用于液体燃料），分散并与传入的空气混合到分子水平。有助于分散和混合的湍流在此过程中至关重要。但是，了解能力如何影响湍流产量仍然是不完整的，从而减慢了高超音速飞行的发展。该项目旨在通过直接测量密苏里科学技术大学的Mach 3风洞中的湍流来调查对湍流的能力影响。由于湍流在混合过程中起着关键作用，了解其产量以及如何受到能力的影响将有助于更好地理解超音速流量的混合过程和超音速对比器的设计。最近已经调查了超音速流中的湍流产生，因此最近调查了可压缩性，尤其是对密度的影响，因此在不合格的情况下进行了越来越多的范围，而越来越多地逐渐被忽略，因此越来越多地逐渐被忽略，而越来越多，而越来越多，而越来越多地逐渐变形。混合应用。最近的研究表明，即使对于Scramjet复合材料的相对低超音速马赫数（占飞行MACH的30-40％），对湍流产生的综合性影响也可以与不可压缩的湍流产生相媲美。该分析基于可用文献的理论参数和有限的实验/数值数据，表明最初是针对边界层开发的强雷诺分析学（速度和密度波动之间的相关性）也适用于无绑定的超音速混合流。该项目的建议是通过直接测量密度和速度波动的两点聚焦激光差异干涉法（2-FLDI）来实验验证强雷诺分析在超音速混合流中的有效性。 2-fldi是一种经过验证的低成本技术，可以允许高频，简单，无逆性的密度和速度波动。该流将包括来自3个Mach 3自由流中的塔式喷射的简单平面喷气机。这项工作还将通过夏令营的发展来支持STEM宣传，并通过支持研究生和本科生，从而在超为人工方面的劳动力发展。这项工作的发现还将被纳入有关动荡流的研究生班。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的审查标准来评估值得通过评估。