Fluid processes in smart microengineered devices: Hydrodynamics and thermodynamics in microspace

目前微流体设备市场规模为20亿美元，预计到2016年将翻一番。这种微器件通常集成在多功能单元中，不仅提供了许多优于传统大规模技术的优点，而且还在许多不同的研究领域提供了许多潜在的用途，这些研究领域利用了受限几何形状中的流体。它们有许多实际应用，包括药物输送（例如，吸入器、微针）、分析装置、护理点诊断、连续流小规模强化制造、药物研究、临床和兽医诊断等。在微通道装置中，流体在受限的几何形状中流动，并且尽管已经取得了显著的进展，但是理解在宽范围的长度尺度上发生的不同现象，从分子尺度过程到宏观流体动力学过程，以及它们之间的相互关系，仍然缺乏。更具体地说，拟议的研究重点是微结构，例如膜，微接触器或图案化衬底，如何影响微空间中多相流的流体力学和热力学;更重要的是，它们如何受到微结构的影响。这样的理解是至关重要的，进一步应用微流体器件和它们的利用热-质transfer enhancement.The微工程器件的研究中存在的微结构拥有许多挑战，从基础和应用研究的角度来看。我们认为，对此类设备进行全面和系统的研究应涉及跨学科的方法，需要使用不同领域的工具和开发新方法。该提案寻求为一项为期四年的综合研究方案提供资金，该方案将采用一种新的协同方法，将联合收割机最先进的实验技术、复杂的计算流体动力学和分子建模以及以前从未尝试过的先进理论物理要素结合起来。我们的目标是合理地理解，并定量表征微结构的受限几何形状的流体过程中，在分子/热力学和流体动力学水平，从而建立在广泛分离的尺度发生的现象之间的连接。作为一个主要的案例研究，我们将考虑微尺度的流体分离，突出了一些目前尚未解决的，但在微工程技术的关键问题，即气液平衡在有限的几何形状和突破过程（即一个相侵入另一个）。我们的主要研究结果也将用于探索微结构发挥核心作用的其他应用，如微蒸馏，或滑流和液滴形成。这项工作将由来自伦敦帝国理工学院化学工程系的团队承担，他们具有互补的技能和优势：Kalliadasis（流体力学/统计力学-计算，理论），加林多（统计力学/分子动力学-计算）和Pradas（统计/理论物理-计算，理论）;和一个来自伦敦大学学院化学工程系的团队：Gavriillem（实验微化学工程和微流体），Kuhn（微流体，多相流建模和实验）和Sorensen（工艺设计，微蒸馏）。

The current microfluidic devices market is $2 Billion and expected to double by 2016. Such microdevices are usually integrated in multifunctional units, which not only offer numerous advantages over traditional large-scale technologies, but also provide a multitude of potential uses in many different research fields that exploit fluids in confined geometries. They have numerous practical applications including drug delivery (e.g. inhalers, microneedles), analytical devices, point of care diagnostics, continuous flow small scale intensified manufacturing, pharmaceutical research, clinical and veterinary diagnostics, etc. In microchannel devices fluids flow in confined geometries and although significant progress has been made, understanding how the different phenomena occurring across a wide range of lengths scales, from molecular-scale processes to macroscopic hydrodynamic ones, and how they are related to each other, is still lacking. More specifically, the proposed research focuses on how microstructures, e.g. membranes, microcontactors, or patterned substrates, affect the hydrodynamics and thermodynamics of multiphase flows in microspace; and more importantly how they are influenced by the presence of the microstructure. Such understanding is critical for furthering the applications of microfluidic devices and their utilisation for heat-mass transport enhancement.The study of microengineered devices in the presence of microstructure posseses many challenges from both a fundamental and applied research point of view. It is our belief that a complete and systematic study of such devices should involve an interdisciplinary approach that requires the use of tools and the development of new methodologies from different areas. This proposal seeks funding for a comprehensive four-year research programme into a novel synergistic approach that will combine state-of-the-art experimental techniques, sophisticated computational fluid dynamics and molecular modeling as well as advanced theoretical physics elements, never attempted before. We aim at rationally understanding, and quantitatively characterising fluid processes in microstructured confined geometries, on both the molecular/thermodynamic and hydrodynamic level, hence establishing connections between phenomena occurring at widely separated scales. As a main case study we shall consider microscale fluid separation which highlights some of the currently unresolved, yet key issues in microengineering technology, namely vapour-liquid equilibrium in confined geometries and breakthrough process (i.e. one phase invading into another). Our main findings will also be used to explore other applications where microstructures play a central role, such as microdistillation, or slip flows and droplet formation. The work will be undertaken by a team from the Chemical Engineering Department at Imperial College London with complementary skills and strengths: Kalliadasis (Hydrodynamics/Statistical Mechanics -- Computations, Theory), Galindo (Statistical Mechanics/Molecular Dynamics -- Computations), and Pradas (Statistical/Theoretical Physics -- Computations, Theory); and a team from the Chemical Engineering Department at University College London: Gavriilidis (Experimental Microchemical Engineering and Microfluidics), Kuhn (Microfluidics, Multiphase Flows Modelling and Experiments), and Sorensen (Process Design, Microdistillation).