ERI: Computational Investigation of High-Pressure Turbulent Premixed Flames - Physical Insights and Two-Scale Predictive Modeling

在航空和汽车发动机中可以观察到预混燃烧，这些发动机通常在高压和湍流条件下运行，以产生更高的燃油效率、紧凑的设计和更低的排放。各种燃烧过程的相互作用，如物质传输、化学反应和热释放，使得对这些应用中的火焰-湍流相互作用的计算研究成为一项具有挑战性的任务，特别是当详细的化学描述是必不可少的时候。过去的基础研究主要集中在对大气压下这种火焰的分析。在这项工作中，高压湍流预混火焰的各个方面将通过提供对压力影响的基本见解和建立有效的基于物理的计算模型来解决。这项研究还将通过丰富流体力学和热学的课程，将研究和教育结合起来；赋予不同背景的本科生和研究生先进的知识和计算技能；并指导大学支持的本科生发展目标和技能。在能量转换和推进装置中观察到的高压湍流预混火焰具有多尺度性质，这使得他们的基础研究极具挑战性。虽然直接数值模拟可以提供对火焰-湍流相互作用的详细了解，但它往往在计算上阻碍了实际应用的研究。为此，大涡模拟是一种很有前途的建模策略；然而，需要解决一些挑战，才能使其具有预测性。此外，过去的大多数基础研究都集中在研究大气压下这种火焰的特征，因此需要进一步研究，特别是侧重于分析火焰区内的多尺度相互作用。这项建议将通过(I)提供关于压力对正则构型中预混火焰-湍流相互作用的影响的基本见解，(Ii)评估基于物理的新的双尺度预测建模策略的能力，以及(Iii)研究不同类型燃料在高压条件下的行为，来应对这些挑战。该项目的成果将对湍流燃烧领域产生更广泛的影响，因为它将有助于更好地了解高压湍流预混火焰的特征，并展示可用于研究实际结构的多尺度模型的能力。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。

Premixed combustion is observed in aeronautical and automotive engines, which are typically operated at high pressure and under turbulent flow conditions to yield higher fuel efficiency, compact design, and lower emissions. The interplay of various combustion processes such as species transport, chemical reactions, and heat release makes the computational investigation of flame-turbulence interactions in these applications a challenging task, particularly when a detailed chemical description is essential. Past fundamental studies have primarily focused on the analysis of such flames at atmospheric pressure. In this work, aspects of high-pressure turbulent premixed flames will be addressed by providing fundamental insights into the effects of pressure and establishing an efficient physics-based computational model. This investigation will also integrate research and education by enriching courses in fluid mechanics and thermal sciences; empower undergraduate and graduate students from diverse backgrounds with advanced knowledge and computational skills; and mentor university-supported undergraduate scholars to develop goals and skills.High-pressure turbulent premixed flames observed in energy conversion and propulsion devices are multi-scale in nature, which makes their fundamental investigation extremely challenging. While direct numerical simulation can provide detailed insights into flame-turbulence interactions, it tends to be computationally prohibitive for the study of practical applications. To this end, large-eddy simulation is a promising modeling strategy; however, some challenges need to be addressed for it to be predictive. Additionally, most of the past fundamental studies have focused on examining the characteristics of such flames at atmospheric pressure, thus requiring further studies, particularly, focusing on the analysis of the multi-scale interactions within the flame region. This proposal will address these challenges by (i) providing fundamental insights into the effects of pressure on premixed flame-turbulence interactions in canonical configurations, (ii) assessing the capabilities of a novel two-scale physics-based predictive modeling strategy, and (iii) examining the behavior of different types of fuels under high-pressure conditions. The outcomes of the project will have a broader impact on the field of turbulent combustion as it will lead to an improved understanding of features of high-pressure turbulent premixed flames, and demonstrate the capabilities of a multi-scale model, which can be used to study practical configurations.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.