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.

本文采用大涡模拟（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扰。该研究课题代表了湍流热、质量和流体流动领域复杂的多尺度物理现象，在机械、化学和环境工程中有着广泛的应用。例如，射流和标量的湍流混合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）的输运过程由喷管形状、喷管分离距离、雷诺数、施密特数、格拉什夫数以及羽流和湍流涡的长度尺度等诸多因素决定。此外，通过分离瞬时湍流和非湍流（T/NT）流区的动态演化双射流界面进行的吞没和夹带过程在湍流混合过程中起着重要作用。