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）研究了不同形状喷嘴发射的双射流和双标量的湍流干涉。该研究课题代表了湍流热、质量和流体流动领域的复杂多尺度物理现象，在机械、化学和环境工程中具有广泛的应用。例如，关于射流和标量的湍流混合的知识对于设计战斗机的高效双喷气发动机排气和车辆的双消声器至关重要。动量和标量（被动或主动）的传输过程由许多因素决定，例如喷嘴形状、喷嘴间距、雷诺数、施密特数、格拉霍夫数以及羽流和湍流涡流的长度尺度。此外，通过动态演变的双射流界面分离瞬时湍流和非湍流（T/NT）流动区域的吞没和夹带过程在湍流混合过程中发挥着重要作用。 这项研究的长期目标是深入了解射流湍流干涉和标量混合的物理知识，增强对湍流理论的基本理解和工程应用的实践技能，并开发高保真模拟工具来改进湍流现象的数值预测。第一个短期目标侧重于研究不同形状喷嘴喷出的双射流的干涉。 2D 和 3D 射流都将进行测试，从平面、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喷射。双射流的 LES 结果将分别与高雷诺数和低雷诺数下的实验数据和 DNS 数据进行比较。第二个短期目标包括更高程度的复杂性，以及由于使用主动标量而产生的额外体积力。为此，将研究浮力射流，并研究浮力对动量和热能耦合传输的影响。第三个短期目标是开发和测试几种新颖的亚网格尺度模型，以改进湍流和标量混合的 LES 预测。 拟议的研究将为申请人及其学生提供一个利用 DNS 和 LES 对双喷流和双羽流湍流干涉进行创新研究的绝佳机会。通过所提出的研究获得的先进知识和开发的数值工具具有重要的理论和实践价值。拟议的研究还将提供宝贵的机会，在数值建模、工程流体力学、传热传质以及基于内部计算机代码和超级计算机的高性能科学计算相关领域培训高素质人才（HQP）。