RESEARCH INITIATION AWARD: TAILORING JET INSTABILITIES USING ULTRASONIC MICROACTUATORS

研究启动奖：使用超声波微执行器调整射流不稳定性

• 批准号: 1504865
• 负责人: John Solomon
• 金额: $ 20万
• 依托单位: Tuskegee University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1504865&HistoricalAwards=false
• 关键词: RESEARCH; INITIATION; AWARD; TAILORING; JET

Research Initiation Awards provide support for junior and mid-career faculty at Historically Black Colleges and Universities who are building new research programs or redirecting and rebuilding existing research programs. It is expected that the award helps to further the faculty member's research capability and effectiveness, improves research and teaching at his home institution, and involves undergraduate students in research experiences. The award to Tuskegee University has potential broader impact in a number of areas. The goal of the project is to study fundamental characteristics of jet instability and its potential alteration using an ultra-frequency micro-fluidic actuation technique called resonance enhanced microjets (REM). Instability modification, using REM, has potential applications in augmentation of air-fuel mixing in supersonic flow and control of jet noise. Undergraduate students will gain research experience in experimental fluid mechanics. A course in experimental fluid mechanics that includes topics such as digital data acquisition, random data analysis and gas dynamics will be developed.This project includes the design and fabrication of REM in the ultra-frequency range (above 20 kHz) and the study of their interaction and impact on shear layer dynamics of an air jet in free and cross-flow configuration. The jet properties will be studied using unsteady intrusive probes as well as non-intrusive techniques such as laser based microschlieren and planar scattering imaging. The proposed micro-actuation scheme is expected to modify inherent instabilities of a jet, exciting the most unstable modes and generating high frequency three dimensional vorticities for enhanced entrainment and diffusion. The actuators proposed here can produce high momentum pulsed disturbances up to 50 kHz generating instabilities every 20 microseconds in the cross-flow jet. Since such a time scale is very close to the mixing time of a high-speed combustor, this approach is expected to potentially enhance air-fuel mixing in supersonic flows. Fundamental studies on such a tailored jet flowfield will be useful for designing high-speed combustors with improved air-fuel mixing and flame stability.

研究启动奖为历史悠久的黑人学院和大学的初级和中级教师提供了支持，他们正在构建新的研究计划，或重新指导和重建现有的研究计划。预计该奖项有助于进一步促进教职员工的研究能力和有效性，改善他的家庭机构的研究和教学，并让本科生参与研究经验。 塔斯基吉大学的奖项在许多领域都具有更广泛的影响。该项目的目的是使用一种称为共振增强的微型微晶体（REM）的超频微氟促进技术来研究喷气不稳定性的基本特征及其潜在改变。使用REM的不稳定性修饰具有扩大超音速流动和射流噪声控制中空气混合的潜在应用。本科生将获得实验流体力学的研究经验。将开发一门实验流体力学的课程，其中包括数字数据获取，随机数据分析和气体动态等主题。本项目包括在超频范围内的REM的设计和制造（20 kHz以上）以及对其研究的研究在自由和跨流配置中对空气射流的剪切层动力学的相互作用和影响。将使用不稳定的侵入性探针以及非侵入性技术（例如基于激光器的微旋晶和平面散射成像）来研究喷气性能。预计所提出的微型分子方案将修改喷气机的固有不稳定性，激发最不稳定的模式，并产生高频三维涡度，以增强夹带和扩散。此处提出的执行器可以在跨流射流中每20微秒产生高达50 kHz的不稳定性。由于这样的时间尺度非常接近高速燃烧器的混合时间，因此预计这种方法有可能增强超音速流中的空气燃料混合。对这种量身定制的喷气流场的基本研究将有助于通过改进的空气燃料混合和火焰稳定性设计高速燃烧器。

项目成果

Design and Characterization of Nozzle-Injection Assemblies Integrated with High-Frequency Microactuators

与高频微执行器集成的喷嘴喷射组件的设计和表征

• DOI: 10.2514/1.j056642
• 发表时间: 2018
• 期刊: AIAA Journal
• 影响因子: 2.5
• 作者: Solomon, John T.;Caines, Kyran;Nayak, Chitra R.;Jones, Michael;Alexander, David
• 通讯作者: Alexander, David