Numerical analysis of particle-turbulence interaction in high-speed gas flows

高速气流中粒子-湍流相互作用的数值分析

• 批准号: 422012568
• 负责人: Dr.-Ing. Lennart Schneiders
• 金额: --
• 依托单位: Computational Flow Physics Group
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/422012568?language=en
• 关键词: Numerical; analysis; particle; turbulence; interaction

The interaction of high-speed gas flows with dispersed solid particles or droplets plays a decisive role in various geophysical, astrophysical, and technical processes. Examples include explosive volcanic eruptions, the formation of supernovae, cold spraying to deposit surface coatings, and supersonic combustion engines. These multiphase systems are characterized by a complex interplay of gas-phase turbulence, particle dynamics, heat transfer, and compressibility effects such as shock waves. Despite the large variety of applications, the fundamental mechanisms of particle-turbulence interaction in these flows are still poorly understood. The large number of involved physical effects and the vast range of different length and time scales exacerbate numerical analyses of these systems. Similarly, these conditions often prevent detailed experimental measurements. The lack of fundamental understanding inhibits the development of particle and turbulence models; however, accurate models are indispensable for predictive simulations in the above mentioned applications. As an example, the impact of explosive volcanic eruptions on the nearby population, aviation, and global climate is barely predictable due to the current lack of models describing the interaction of gas, magma, and rock fragments at very high velocities.In this project, novel highly-resolved numerical analyses of particle-turbulence interaction in the presence of pronounced compressibility effects and heat transfer will be conducted to enable model development and validation. The canonical flow problem of isotropic turbulence is considered which facilitates to gain understanding of the fundamental mechanisms which determine the multiphase interaction. Using an efficient numerical method recently developed by the applicant, the turbulent motion and the flow field around each particle will be fully resolved via the physical conservation laws. This approach yields an accurate description of the multiphase interaction which has not been documented for this class of flows previously. The data will provide new insight into the mutual influence of particles and compressible turbulence, e.g., detailing the momentum and energy balances of both phases. By comparison with these reference solutions, the accuracy of existing, yet never validated particle models will be analyzed. Furthermore, based on the gained knowledge and mechanistic approaches, new models will be developed. The thorough definition of the models and their range of validity is crucial for the accuracy of applied simulations.

高速气流与分散的固体颗粒或液滴的相互作用在各种地球物理、天体物理和技术过程中起着决定性的作用。例子包括爆炸性火山爆发、超新星的形成、冷喷涂以存款表面涂层和超音速燃烧发动机。这些多相系统的特征在于气相湍流、颗粒动力学、传热和压缩性效应（例如冲击波）的复杂相互作用。尽管有各种各样的应用，在这些流动中的颗粒湍流相互作用的基本机制仍然知之甚少。大量涉及的物理效应和广泛的不同长度和时间尺度加剧了这些系统的数值分析。类似地，这些条件常常妨碍详细的实验测量。缺乏基本的理解抑制了颗粒和湍流模型的发展，然而，准确的模型是不可缺少的预测模拟在上述应用中。例如，由于目前缺乏描述气体、岩浆和岩石碎片在极高速度下相互作用的模型，爆炸性火山爆发对附近人口、航空和全球气候的影响几乎无法预测。新的高分辨率的粒子数值分析，在存在明显的可压缩性效应和热传递的情况下，将进行湍流相互作用，以使模型开发和验证成为可能。各向同性湍流的正则流问题被认为是有利于获得的基本机制，确定多相相互作用的理解。使用申请人最近开发的有效数值方法，将通过物理守恒定律完全解析每个颗粒周围的湍流运动和流场。这种方法产生的多相相互作用，这还没有被记录为这类流量以前的准确描述。这些数据将为颗粒和可压缩湍流的相互影响提供新的见解，例如，详细说明了两个阶段的动量和能量平衡。通过与这些参考解决方案进行比较，将分析现有但从未验证过的粒子模型的准确性。此外，基于所获得的知识和机械方法，将开发新的模型。模型及其有效性范围的彻底定义对于应用模拟的准确性至关重要。