Two-phase flow numerical model development based on experimental characterization.

基于实验表征的两相流数值模型开发本研究计划旨在设计创新实验并建立两相流的理论框架。对于工业应用，控制流的Navier-Stokes方程是平均的。这种平均过程造成了小尺度现象信息的损失。因此，需要对这些现象进行模拟，以充分接近数值模型。我们一直关注的是创造实验来理解和模拟这些小规模的现象，作为我研究目标的指导方针。新开发的模型将在基于平均Navier-Stokes方程的数值代码中实现，并通过与大规模现象实验的比较来验证。这种特殊的哲学创造了通常分别进行的数值和实验方法之间的协同作用。三个具体目标支持这一研究愿景：a)模拟两相流-结构相互作用：第一个项目将研究复合材料制造中树脂注射过程中由于纤维结构的双重尺度而产生的气泡形成。第二个项目将研究两相边界层特征。从两相流的经验关联中制定出壁面定律，可以以合理的成本对工业中遇到的复杂几何形状进行数值预测，并且比目前的预测质量好得多。b)确定粒子-粒子相互作用：第一个项目将通过观察几个气泡合并来研究两相流中气泡之间合并的现象。这种结合是控制气泡大小的平衡的一部分，因此最终决定了它们的轨迹。第二个项目将利用创新的技术测量工具来测量气泡引起的湍流。c)构建对浸没粒子的作用力的相关性：第一个项目将对靠近墙壁上升的气泡进行数值评估。第二个项目将研究一些粒子的升力。如果孤立粒子的力系数的相关关系是相对已知的，其相应的相关关系仍然需要改进。放置在移动的钟和固定的墙之间的气泡云将被监控。第三个项目将通过观察气泡上升的尾迹来研究气泡的阻力，这得益于3D PIV。因此，我们建议将研究重点放在基础实验上，以建立一个准确和一致的分散流动模拟公式。这项创新研究将导致更好的计算模型的发展，以深入了解影响加拿大人口福利和加拿大工业竞争力的各种两相流问题。由于缺乏可靠的两相流数值计算方法，阻碍了在许多采用两相流的工业过程中取得突破。

Two-phase flow numerical model development based on experimental characterization The proposed research program is built to design innovative experiments and develop a theoretical framework for two-phase flows. For industrial applications, the Navier-Stokes equations governing the flows are averaged. This averaging process produces a loss of information on small-scale phenomena. Consequently, modeling these phenomena is required to adequately close numerical models. Our constant concern will be to create experiments to understand and model these small-scale phenomena as the guideline of my research objectives. New developed models will then be implemented in numerical codes based on the averaged Navier-Stokes equations and validated by comparison with large-scale phenomenon experiments. This specific philosophy creates a synergy between numerical and experimental approaches often conducted separately. Three specific objectives support this research vision: a) Model two-phase flow-structure interactions: A first project will study the bubble formation occuring during resin injection for composite manufacturing due to the double scale of the fibre structure. A second project will study the two-phase boundary layer characteristics. Formulating a law of the wall from empirical correlations for two-phase flows would allow numerical predictions at a reasonable cost for complex geometries such as those encountered in the industry and of much better quality than current predictions. b) Determine Particle-particle interactions: A first project will study the phenomenon of coalescence between bubbles inside a two-phase flow, by observing a few bubbles coalescing. The coalescence is part of the balance that governs the bubble sizes and therefore ultimately their trajectories. A second project will measure the turbulence induced by bubbles thanks to innovative technical measurement tools. c) Construct correlation for forces on submerged particles: A first project will numerically assess a bubble rising close to a wall. A second project will study the lift forces of a few particles. If correlations of the force coefficient for isolated particles are relatively well known, their corresponding correlation still requires improvements. A cloud of bubbles placed between a moving bell and a fixed wall will be monitored. A third project will study the drag of a bubble by observing the wake of a rising bubble thanks to 3D PIV. Thus, the research we propose will focus on fundamental experiments to construct an accurate and consistent formulation for dispersed flow simulations. This innovative research will lead to the development of better computational models to shed insight into a variety of two-phase flow problems that affect the welfare of the Canadian population and the competitiveness of the Canadian industry. The lack of reliable two-phase flow numerical procedures prevents breakthrough on the numerous industrial processes using two-phase flow.