Study of Dual-Jet Interference and Scalar Mixing using Direct Numerical and Large-Eddy Simulations

使用直接数值和大涡模拟研究双射流干涉和标量混合

• 批准号: RGPIN-2019-06735
• 负责人: Wang, BingChen
• 金额: $ 2.33万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=716367
• 关键词: Study; Dual; Jet; Interference; Scalar

In this research, turbulent interference of dual jets and dual scalars emitted from different shaped nozzles is investigated using large-eddy simulations (LES) and direct numerical simulations (DNS). This research subject represents a complex multi-scale physical phenomenon in the area of turbulent heat, mass and fluid flows, and has vast applications in mechanical, chemical and environmental engineering. For example, the knowledge on turbulent mixing of jets and scalars is critically important for designing highly-efficient twin-jet engine exhausts of a fighter aircraft and twin mufflers of a vehicle. The transport processes of momentum and scalars (passive or active) are determined by many factors such as the nozzle shape, nozzle separation distance, Reynolds number, Schmidt number, Grashof number, and length scales of the plumes and turbulent eddies. Furthermore, the engulfing and entrainment processes through the dynamically evolving dual-jet interfaces that separate the instantaneous turbulent and non-turbulent (T/NT) flow regions play a significant role in the turbulent mixing processes. The long-term objective of this research is to obtain in-depth knowledge on the physics of turbulent interference of jets and mixing of scalars, to enhance our fundamental understanding of turbulence theory as well as practical skills in engineering applications, and to develop high-fidelity simulation tools for improved numerical prediction of turbulence phenomena. The first short-term objective focuses on a study of the interference of dual jets emitted from different shaped nozzles. Both 2D and 3D jets will be tested, emitting from planar, round and concentric circular nozzles, and from elliptic and rectangular nozzles of different aspect ratios. The LES results on dual jets will be compared against experimental and DNS data at high and low Reynolds numbers, respectively. The second short-term objective includes one more degree of complexity, an additional body force due to the use of active scalars. To this purpose, buoyant jets will be studied, and the effect of buoyancy on the coupled transport of momentum and thermal energy will be investigated. The third short-term objective is to develop and test several novel subgrid-scale models for improved LES predictions of turbulent flow and scalar mixing. The proposed research will provide an excellent opportunity for the applicant and his students to conduct innovative research on turbulent interference of dual-jets and dual-plumes using both DNS and LES. The advanced knowledge gained and numerical tools developed through the proposed research are of significant theoretical and practical values. The proposed research will also provide a valuable opportunity to train highly qualified personnel (HQP) in areas related to numerical modelling, engineering fluid mechanics, heat and mass transfer, and high-performance scientific computing based on the use of in-house computer codes and supercomputers.

在这项研究中，使用大涡模拟（LES）和直接数值模拟（DNS）研究了从不同形喷嘴发出的双流量和双重标量的湍流干扰。该研究主题代表了湍流，质量和流体流动区域中一种复杂的多尺度物理现象，并且在机械，化学和环境工程中具有广泛的应用。例如，关于喷气机和标量的湍流混合的知识对于设计高效的双喷射机的排气装置至关重要。动量和标量（被动或主动）的传输过程由许多因素（例如喷嘴形状，喷嘴分离距离，雷诺数，schmidt数字，grashof数字和长度尺度）等许多因素确定。此外，通过动态发展的双喷射界面吞没和夹带过程，将瞬时湍流和非扰动（T/NT）流动区域分开，在湍流混合过程中起着重要作用。 这项研究的长期目的是获得有关喷气式干扰和标量混合的湍流干扰物理学的深入了解，以增强我们对湍流理论以及工程应用中的实践技能的基本理解，并开发高保真模拟工具，以改善湍流现象的数值预测。第一个短期客观的重点是研究从不同形喷嘴发出的双重飞机的干扰。 2D和3D喷气机将通过平面，圆形和同心圆形喷嘴以及不同纵横比的椭圆形和矩形喷嘴进行测试。将分别将双重射流的LES结果与雷诺数高和低雷诺数的实验和DNS数据进行比较。第二个短期目标包括一种更高程度的复杂性，这是由于使用主动标量而导致的额外体力。为此，将研究浮力的喷气机，并将研究浮力对动量和热能耦合运输的影响。第三个短期目标是开发和测试几种新型的亚网格规模模型，以改善湍流和标量混合的LES预测。 拟议的研究将为申请人及其学生提供一个极好的机会，以使用DNS和LES进行双重爆炸和双羽状干扰的创新研究。通过拟议的研究获得的先进知识和数值工具具有重要的理论和实际价值。拟议的研究还将为基于内部计算机代码和超级计算机的使用，在与数值建模，工程流体力学，热量和质量转移相关的领域以及高性能科学计算方面提供培训高素质人员（HQP）的宝贵机会。