Turbulent multiphase flow with interfacial mass and heat transfer: linking microscopic physics to macroscopic mixing

CBET -1705246 PI：Ni，Rui许多自然发生的和工业过程涉及包含分散在流体中的颗粒（例如气泡或液滴）的湍流。 在这些情况下，分散相可以以取决于湍流的细节的方式与周围流体交换质量和热量。 该奖项将支持实验，以了解质量和热量传递对湍流大规模统计的作用。 挑战在于将单个气泡或液滴尺度上的微观传质与宏观混合和传质联系起来。垂直水洞将被用来研究气泡，可以保持静止和成像，以确定示踪剂的浓度场之间交换的气泡和周围的流体。 质量交换速率将与描述湍流强度和分散相特性的参数相关。 LED照明系统将用于量化湍流中的温度分布，这提供了对蒸汽气泡的大规模混合效率的洞察。该系统还将用于研究各种形状的颗粒的浓度，以分析湍流中的混合。 这些研究的结果将广泛相关的应用，如蒸发喷雾，云中的雨滴，发酵反应器中的气泡，和多相化学反应器。该研究小组将为参加宾夕法尼亚州立大学项目的K-12学生团体和宾夕法尼亚州中部艺术节准备多相流演示。一个垂直隧道设施将用于研究载有颗粒的湍流中的传质。 相反的平均流平衡颗粒的浮力驱动上升或沉降，这允许颗粒保持在用于成像的视场中。 该设备允许独立地调整平均流和湍流雷诺数。 将使用成像方法的组合来测量分散颗粒的三维拉格朗日轨迹、周围流的统计以及通过界面转移在两相之间交换的质量的浓度场。 将进行实验以确定具有界面传递的湍流多相流的相关参数。 将检查包含气泡和其他具有惯性的颗粒的流，以确定惯性颗粒是否增强传质和混合。 界面动量传递和质量传递之间的双向耦合的可能性将被调查。 将确定界面传质对气泡破裂和合并的作用。

CBET - 1705246PI: Ni, RuiMany naturally occurring and industrial processes involve turbulent flows that contain particles such as bubbles or drops dispersed in a fluid. In these cases, the dispersed phase can exchange mass and heat with the surrounding fluid in a way that depends on details of the turbulent flow. This award will support experiments to understand the role of mass and heat transfer on large-scale statistics of turbulent flows. The challenge is to relate microscopic mass transfer on the scale of individual bubbles or drops to macroscopic mixing and mass transport. A vertical water tunnel will be used to study bubbles that can be held stationary and imaged to determine the concentration field of tracers that are exchanged between the bubbles and surrounding fluid. The rate of mass exchange will be correlated with parameters that describe the turbulence intensity and characteristics of the dispersed phase. An LED illumination system will be used to quantify temperature profiles in turbulent flow, which provides insight into large-scale mixing efficient of vapor bubbles. This system will also be used to study the concentrations of particles of various shapes to analyze mixing in turbulent flow. The results of these studies will be broadly relevant to such applications as evaporating sprays, rain droplets in clouds, air bubbles in fermentation reactors, and multiphase chemical reactors. The research team will prepare demonstrations of multiphase flows for K-12 student groups participating in programs at Penn State and for the Central Pennsylvania Festival of the Arts.A vertical tunnel facility will be used to study mass transfer in particle-laden turbulent flows. An opposing mean flow balances the buoyancy drive rise or settling of particles, which allows the particles to remain in a field of view for imaging. The facility allows the mean flow and the turbulence Reynolds number to be adjusted independently. A combination of imaging methods will be used to measure the three-dimensional Lagrangian trajectories of dispersed particles, statistics of the surrounding flow, and the concentration field of mass exchanged between the two phases by interfacial transfer. Experiments will be conducted to identify the relevant parameters for turbulent multiphase flow with interfacial transfer. Flows containing bubbles and other particles with inertia will be examined to determine if inertial particles enhance mass transfer and mixing. The possibility of two-way couplings between interfacial momentum transfer and mass transfer will be investigated. The role of interfacial mass transfer on breakup and coalescence of bubbles will be determined.