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.

研究启动奖为传统黑人学院和大学的初级和中期职业教师提供支持，他们正在建立新的研究项目或重新指导和重建现有的研究项目。期望该奖项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可能在许多领域产生更广泛的影响。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改变，使用超频微流体驱动技术称为共振增强微射流（REM）。利用快速动波进行不稳定性修正，在增强超音速气流中空气-燃料混合和控制射流噪声方面具有潜在的应用前景。本科生将获得实验流体力学的研究经验。开设实验流体力学课程，内容包括数字数据采集、随机数据分析和气体动力学。本项目包括设计和制造超频（20khz以上）的REM，并研究它们的相互作用和对自由和横流射流剪切层动力学的影响。射流特性研究将使用非定常侵入探针以及非侵入技术，如激光微纹影和平面散射成像。所提出的微驱动方案有望改变射流固有的不稳定性，激发最不稳定的模态，并产生高频三维涡度，以增强携射和扩散。本文提出的致动器可以在横流射流中产生高达50 kHz的高动量脉冲扰动，每20微秒产生一次不稳定。由于这个时间尺度非常接近高速燃烧室的混合时间，因此这种方法有望潜在地增强超音速流动中的空气-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更好的空气-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