Direct Numerical Simulation of Film Flows on Microstructured Surfaces with absorption of a gas phase

结构化的高性能填料，例如填料柱和降膜蒸发器，其溢出表面的微观结构的几何尺寸与液体滴流膜厚度（< 1mm）的几何尺寸相同。液滴膜中质量输运与流体动力学耦合的表征对于多相过程工程装置的精确描述是非常重要的。由于对各种表面结构上和周围的流动的实验分析，特别是在没有进一步影响流动的情况下，非常复杂和复杂，因此对依赖性的原因研究不够。在项目的第一阶段，成功地研究了微观结构对水动力的影响。基于此，本研究项目的目的是采用直接数值模拟的方法系统地研究单个和周期性排列的微观结构对液膜流动和气体组分吸收的流体动力学的影响。在这样做的基础研究，以回答这个问题，微观结构如何影响质量输运膜流？将进行。在模拟中，使用了完整的Navier-Stokes方程和未进一步简化的紊流模型以及相间动量和质量输运模型。通过对所有发生的时间尺度和长度的分辨，可以很近地观察膜内的交叉混合和界面表面的动力学，并可以系统地研究各种微观结构对传质的影响。模拟结果将加深对微观结构对流体流动和质量输运影响的基本认识。此外，这些基础研究可以阐明柱尺寸的半经验方程，并扩展科学知识，例如，给出新表面设计的细节。

Structured high-performance packing, as found for example in packed columns, and falling film evaporators can have microstructures on the overflown surfaces with geometrical dimensions in the same order of magnitude as the thicknesses of liquid trickle films (< 1 mm). The characterization of the mass transport coupled with the fluid dynamics in the liquid trickle film is very important for the precise description of these multiphase process engineering apparatuses. Since the experimental analysis of the flow over and around the various surface structures, particularly without further influencing the flow, is very involved and complex, the reasons for the dependence are insufficiently researched. During the first project phase the influence of the microstructures on the hydrodynamik was successfully researched. Based on that the aim of this research project is therefore the systematic investigation of the influence of individual and periodically arranged microstructures on the hydrodynamics of liquid film flow and absorption of a gaseous component using Direct Numerical Simulation. In doing so, fundamental research to answer the question How do microstructures influence the mass transport in film flows? will be undertaken. For the simulations, the complete Navier-Stokes equations and no further simplified models for turbulent flows as well as momentum and mass transport between the phases are used. Through the resolution of all occurring length and time scales the cross-mixing in the film and the dynamics of the interfacial surface can be observed very closely and the influence of various microstructures on the mass transfer can be systematically investigated. The simulations are expected to deepen the basic understanding of the influence of the microstructures on the flow and the mass transport. Moreover, these fundamental investigations can elucidate the semi-empirical equations for the dimensioning of columns and extend the scientific knowledge to, for example, give details on the design of novel surfaces.