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观察到预混合燃烧，这些发动机通常在高压和湍流条件下操作，以产生更高的燃料效率、紧凑的设计和更低的排放。各种燃烧过程的相互作用，如物种运输，化学反应，和热释放，使得在这些应用中的火焰湍流相互作用的计算研究具有挑战性的任务，特别是当一个详细的化学描述是必不可少的。过去的基础研究主要集中在大气压力下的火焰分析。在这项工作中，高压湍流预混火焰的方面将通过提供基本的见解，压力的影响，并建立一个有效的基于物理的计算模型。这项调查还将通过丰富流体力学和热科学课程来整合研究和教育;使来自不同背景的本科生和研究生掌握先进的知识和计算技能;并指导大学支持的本科学者发展目标和技能。在能量转换和推进装置中观察到的高压湍流预混火焰本质上是多尺度的，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详细的见解火焰湍流相互作用，它往往是计算上的实际应用的研究禁止。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，使其具有预测性。此外，大多数过去的基础研究都集中在检查这种火焰在大气压力下的特性，因此需要进一步的研究，特别是集中在火焰区域内的多尺度相互作用的分析。该提案将通过以下方式解决这些挑战：（i）提供关于压力对规范配置中预混火焰-湍流相互作用的影响的基本见解，（ii）评估基于物理学的新型双尺度预测建模策略的能力，以及（iii）检查高压条件下不同类型燃料的行为。该项目的成果将对湍流燃烧领域产生更广泛的影响，因为它将导致对高压湍流预混火焰特征的更好理解，并展示多尺度模型的能力，该奖项反映了NSF的法定使命，并通过使用基金会的智力价值进行评估，更广泛的影响审查标准。

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.