CAREER: Structure and Dynamics of Highly Turbulent Premixed Combustion

在包括发动机、燃气轮机甚至超新星爆炸在内的一系列工程和自然系统中，都可以发现高度湍流的预混火焰。目前这一领域的许多知识都是从使用相对简单的化学模型的理想化构型的数值模拟中获得的。为了满足对更逼真的需求，该项目将使用先进的计算工具和更复杂的化学模拟来研究实际相关构型中高度湍流预混火焰的特征和行为。最终，该项目产生的物理洞察力将使先进能源系统的模拟更加准确。作为对该项目研究目标的补充，将为代表不足的少数族裔学生设立一个新的计算流体力学暑期讲习班。这个研讨会的目标是让来自各种背景的下一代科学家和工程师获得模拟真实世界能源系统的经验。这些学生将提高他们对工程设计过程的理解，并意识到与继续使用燃烧发电相关的环境和工程问题。这项研究将利用自适应网格细化(AMR)来克服模拟更复杂的实际构型的计算成本，包括那些二次流、剪切、漩涡和墙很重要的构型。使用AMR，将进行新的直接数值模拟，并将使用拉格朗日和尺度相关诊断来检验结果数据集，以解决三个基本问题：(I)高强度湍流如何影响预混火焰的结构、动力学和化学路径？(Ii)预混火焰对湍流结构和动能动力学有何影响？(3)火焰特性如何取决于结构和运行条件？研究的结构包括钝体稳定火焰、相互作用的射流和本生火焰以及旋流多喷嘴燃烧室。每个模拟都将在与实验者密切合作的情况下进行，从而验证所有结果。除了完善高度湍流燃烧的理论和模型，拟议的项目还将通过公开共享每个模拟的数据和统计数据，以及所有分析代码和诊断工具来影响更广泛的燃烧社区。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Highly turbulent premixed flames are found in a range of engineering and natural systems, including engines, gas turbines, and even supernova explosions. Much of the current knowledge in this area has been obtained from numerical simulations of idealized configurations using relatively simple chemical models. To address the need for greater realism, this project will use advanced computational tools and more sophisticated chemical modeling to study the characteristics and behaviors of highly turbulent premixed flames in practically relevant configurations. Ultimately, physical insights resulting from this project will enable more accurate simulations of advanced energy systems. Complementary to the research goals of this project, a new summer workshop on computational fluid dynamics will be established for under-represented minority students. The goal of this workshop is to give the next generation of scientists and engineers, from all backgrounds, experience in modeling real-world energy systems. These students will improve their understanding of the engineering design process as well as become aware of the environmental and engineering issues related to the continued use of combustion for energy generation.This research will make use of adaptive mesh refinement (AMR) for overcoming the computational cost of simulating more complex practical configurations, including those where secondary flows, shear, swirl, and walls are important. Using AMR, new direct numerical simulations will be performed, and the resulting datasets will be examined using Lagrangian and scale-dependent diagnostics to address three fundamental questions: (i) How does high intensity turbulence affect premixed flame structure, dynamics, and chemical pathways? (ii) How are turbulence structure and kinetic energy dynamics affected by premixed flames? (iii) How do flame properties depend on configuration and operating conditions? The configurations examined will include bluff-body stabilized flames, interacting jet and Bunsen flames, and swirling multi-nozzle combustors. Each of the simulations will be performed in close collaboration with experimentalists, allowing validation of all results. In addition to refining theories and models of highly turbulent combustion, the proposed project will impact the broader combustion community by publicly sharing data and statistics from each of the simulations, as well as all analysis codes and diagnostic tools.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.