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.

研究启动奖为历史上黑人学院和大学的初级和中级职业教师提供支持，他们正在建立新的研究项目或重新定向和重建现有的研究项目。预计该奖项将有助于进一步提高教师的研究能力和效率，改善其所在机构的研究和教学，并使本科生参与研究经验。 授予塔斯基吉大学的奖项在许多领域具有潜在的更广泛的影响。该项目的目标是研究射流不稳定性的基本特征及其潜在的变化，使用超高频微流体驱动技术，称为共振增强微射流（REM）。利用REM技术进行不稳定性修正在超声速流场的掺混和喷流噪声控制方面具有潜在的应用价值。本科生将获得实验流体力学的研究经验。将开设一门实验流体力学课程，包括数字数据采集、随机数据分析和气体动力学等主题，该项目包括设计和制造超高频范围（20 kHz以上）的REM，并研究它们之间的相互作用以及对自由和横流结构中空气射流剪切层动力学的影响。将使用非定常侵入式探头以及非侵入式技术（如基于激光的微纹影和平面散射成像）研究射流特性。所提出的微致动方案预计将修改固有的不稳定性的射流，激发最不稳定的模式，并产生高频三维涡增强夹带和扩散。这里提出的致动器可以产生高达50 kHz的高动量脉冲扰动，在横流射流中每20微秒产生不稳定性。由于这样的时间尺度非常接近高速燃烧室的混合时间，因此预计这种方法可能会增强超音速流中的空气-燃料混合。对这种定制射流流场的基础研究将有助于设计具有改进的空气燃料混合和火焰稳定性的高速燃烧室。

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