Fundamental Studies of the Thermoacoustic Effect: Interactions of Acoustic Waves with Viscous Fluids

Farouk 0853959这是一个实验和数值研究的声学驱动的粘性流动的谐振器嵌入一层紧密间隔的薄板（堆叠）或紧密包装的平纹编织金属丝网（再生器）。精确和高保真度的计算模型将开发的非线性和时间依赖性的行为，声激励流在可压缩的，粘性和导电流体在这样的设备。这些模型将在我们的实验室进行实验验证。应进行声功率输入对系统影响的优化研究。将进行专门设计的实验，用于测量谐振器（有和没有嵌入式堆栈）中随时间变化的压力，温度和速度场，由具有不同强度和频率的声波的压缩驱动器驱动。这些测量将提供有关压力和速度场的基本数据。 流动可视化研究将确定稳定流动的可能形成及其作为声功率输入的函数的行为。谐振器形状对谐振器中的压力振幅的影响将被确定为压缩驱动器的操作参数的函数。数值求解可压缩流场的Navier-Stokes方程，以获得这些代表性问题中的速度场、压力场和温度场。这项研究将提高目前的复杂程度，在分析各种各样的声学驱动的技术重要性的问题，特别是有关热声制冷机的设计改进。该提案所涉及的问题的跨学科性质将引起广大科学家和工程师的兴趣。PI在计算声学和实验方法领域拥有丰富的经验。PI和他的学生将与来自政府实验室（NRL，华盛顿，DC和NIST，博尔德，CO）和行业（CFIC Inc.，Troy，NY）。对研究生和本科生的培训被纳入该方案，并将努力从代表性不足的群体中招收研究生。开发的软件可用作设计商业规模装置和优化操作条件以达到预期目标的工具。

Farouk0853959This is an experimental and numerical study of acoustically-driven viscous flows in resonators embedded with either a layer of closely-spaced thin plates (a stack) or with close-packed plain-weave metal screens (a regenerator). Accurate and high-fidelity computational models will be developed for nonlinear and time-dependent behavior of acoustically-excited flows in compressible, viscous and conductive fluids in such devices. The models will be validated with experiments to be carried out in our laboratories. Optimization studies of the effects of acoustic power input to the systems shall be conducted. Specially designed experiments will be conducted for measuring the time-dependent pressure, temperature and velocity fields in the resonators (with and without embedded stacks), driven by compression drivers with acoustic waves of varying intensities and frequencies. The measurements will provide fundamental data on the pressure, and velocity fields. Flow visualization studies will determine the possible formation of steady streaming flows and their behavior as a function of acoustic power input. The effects of the resonator shapes on the pressure amplitude in the resonators will be determined as functions of the operating parameters of the compression driver. The Navier-Stokes equations for a compressible flowfield will be solved numerically to obtain the velocity, pressure and temperature fields in these representative problems. This research will enhance the current level of sophistication in analyzing a wide variety of acoustically-driven problems of technological importance, specifically related to the design improvement of thermoacoustic refrigerators. The interdisciplinary nature of the problems addressed in the proposal will interest a broad section of scientists and engineers. The PI has significant past experience in the areas of computational acoustics and experimental methods. The PI and his students will collaborate with leading scientists from government laboratories (NRL, Washington, DC and NIST, Boulder, CO) and industry (CFIC Inc., Troy, NY). The training of both graduate and undergraduate students is integrated into the program and efforts will be made to recruit graduate students from the underrepresented groups. The software developed can be used as a tool for designing commercial scale devices and optimizing the operating conditions to desired goals.