GOALI: Scattering and Excitation of Acoustic Waves by Turbulent Flames

奖项：CBET-0651045题目：GOALI：湍流火焰对声波的散射和激发首席研究员：Tim Lieuwen研究所：佐治亚理工学院研究公司-佐治亚理工学院，亚特兰大，佐治亚州这项拟议的工作将研究声波和湍流预混火焰之间的相互作用。这些过程在各种能源设备中遇到的湍流反应流的动力学中起着重要的作用，例如工业熔炉、内燃机和燃气轮机。这项工作将加深对湍流火焰动力学的理解，这是提高效率和性能、减少有害燃烧室振荡和降低此类系统成本所必需的。在这位研究者之前的工作中，一个关键的成就是建立了一个关于皱纹火焰前锋的声波散射模型。这一分析考虑了质量燃速对声学扰动的响应和皱纹锋面的几何复杂性等因素。这个理论的几个关键预测通过测量得到了证实。然而，这种分析假定火焰的位置是规定的，因此它无法预测声扰动对湍流火焰速度或火焰刷子厚度的影响，这两种影响都是已知的受声激励影响的。本研究的目的是通过求解火焰前缘位置来充分考虑火焰-声学耦合。此外，这项研究将包括对更真实的湍流火焰锋面的计算分析，包括那些具有大规模波纹和凹槽的火焰锋面。对这些声学激发和相互作用过程的理解将有几个基本的和应用的收益。首先，它将有助于更好地理解湍流火焰中发生的动力学过程。其次，这一知识可以用来理解燃烧不稳定性，即火焰与声场相互作用并产生高幅度、破坏性的振荡。第三，它将导致解释声学信号特征的方法，无论是由火焰自然产生的，还是通过对火焰进行诊断应用的“探测”波散射而产生的。该计划还包括一些将在佐治亚理工学院和当地一所公立高中举行的综合教育活动。这一努力的一个关键目标是整合研究、教育和服务。因此，它将把研究结果纳入相关的本科生和研究生课程，提供研究技能培训，并让当地一所高中的教师参与。该项目支持高中的数学和科学教学，鼓励高中生追求科学事业，同时为佐治亚理工学院的学生提供教学、服务和指导经验。

Award: CBET-0651045Title: GOALI: Scattering and Excitation of Acoustic Waves by Turbulent FlamesPrincipal Investigator: Tim LieuwenInstitution: Georgia Tech Research Corporation - Georgia Institute of Technology, Atlanta, GA This proposed effort will investigate the mutual interactions between acoustic waves and turbulent, premixed flames. Such processes play important roles in the dynamics of turbulent reacting flows encountered in various energy devices, such as industrial furnaces, internal combustion engines, and gas turbines. This work will improve understanding of turbulent flame dynamics that is needed to improve efficiency and performance, reduce harmful combustor oscillations, and reduce the cost of such systems.In previous work by this investigator, a key accomplishment was to develop a model for the scattering of sound waves from wrinkled flame fronts. This analysis accounted for such factors as the response of the mass burning rate to acoustic perturbations and the geometric complexities of the wrinkled front. Several key predictions of this theory were confirmed by measurements. However, this analysis assumed that the flame position was prescribed and, thus, it was not able to predict the effects of the acoustic disturbance on turbulent flame speed or flame brush thickness, both known to be influenced by acoustic excitation. The objective of the present research is to include flame-acoustic coupling fully by solving for the flame front position. Furthermore, the research will include computational analyses of more realistic turbulent flame fronts, including those with large scale corrugations and pockets. An understanding of these acoustic excitation and interaction processes will have several fundamental and applied payoffs. First, it will contribute to a better understanding of the dynamical processes occurring in turbulent flames. Second, this knowledge can be used to understand combustion instabilities where flames interact with acoustic fields and generate high amplitude, destructive oscillations. Third, it will lead to ways to interpret the characteristics of acoustic signatures, either naturally generated by the flame or scattered by "probing" waves directed at the flame for diagnostic applications.This program also includes a number of integrated educational activities that will take place within Georgia Tech and at a local public high school. A key objective of this effort is to integrate research, education, and service. As such, it will incorporate findings into relevant undergraduate and graduate courses, provide research-skill training, and involve teachers at a local high school. The project supports teaching of math and science in the high school, and it encourages high school students to pursue careers in the sciences, at the same time providing Georgia Tech students with teaching, service, and mentoring experience.