Direct numerical modelling of interfacial transport mechanisms at microscale

两相流经常出现在自然界和工业应用中，例如海岸工程，陆地，空中和海上推进，能源生产以及医疗诊断和治疗。许多这些两相流包括在微观尺度上的基本界面传输机制。今天，系统，包括界面传输机制和复杂的物理化学现象，在微观上的设计主要基于经验观察，因为一个基本的理论框架和相关的预测工具是不可用的。直接数值模拟（DNS）可以提供一个强大的和具有成本效益的工具来研究和预测两相流的复杂行为和相关的界面输运机制。然而，尽管致力于两相流建模的广泛研究工作，但在微观尺度上模拟界面传输机制仍然存在很大困难。在微观尺度上精确模拟界面输运机制的方法对工业界和学术界来说都是一项使能技术，这将有助于设计新颖和改进的工艺以及更好的消费品，并产生直接的经济和社会影响。拟议的研究对支配微观两相流的复杂物理化学现象和输运机制的前所未有的细节进行了深入研究。拟议的研究包括开拓性的数值技术的发展，在连续介质力学的职权范围内预测在微观尺度上的两相流的复杂行为，以及在两个原型应用与直接工业相关的界面传输机制的研究：a）两相微处理器冷却和B）润滑剂中的泡沫动力学。新的数值技术将解决现有数值方法的关键问题，并使DNS的界面输运机制在微观尺度上在一个合理的计算框架。在微尺度下直接模拟两相流的能力不仅将增加我们对微尺度下控制界面传输机制的复杂物理学的基本理解，而且还将使工程师能够构建依赖于这种流动的更好的设备和系统。通过对原型应用的研究，拟议的研究将提供对微尺度界面传输机制的详细了解，通常与微流体两相流相关，并将直接有助于开发能够处理下一代微处理器产生的热量的冷却系统，以及开发更可靠，高效和经济友好的润滑剂。

Two-phase flows occur frequently in nature and industrial applications, such as coastal engineering, land, air and marine propulsion, energy generation and in medical diagnostics and therapy. Many of these two-phase flows comprise essential interfacial transport mechanisms at microscale. Today, systems that comprise interfacial transport mechanisms and complex physicochemical phenomena at microscale are designed based predominantly on empirical observations, since a fundamental theoretical framework and associated predictive tools are not available. Direct numerical simulation (DNS) can provide a powerful and cost-efficient tool to study and predict the complex behaviour of two-phase flows and the associated interfacial transport mechanisms. However, despite extensive research efforts dedicated to two-phase flow modelling, substantial difficulties remain in simulating interfacial transport mechanisms at microscale. Having the means to accurately simulate interfacial transport mechanisms at microscale is an enabling technology for both industry and academia, which will aid the design of novel and improved processes as well as better consumer products, with direct economical and societal impact.The proposed research conducts an in-depth study of unprecedented detail of the complex physicochemical phenomena and transport mechanisms that govern microscopic two-phase flows. The proposed research includes the development of pioneering numerical techniques in the remit of continuum mechanics to predict the complex behaviour of two-phase flows at microscale as well as the study of interfacial transport mechanisms in two prototypical applications with immediate industrial relevance: a) two-phase microprocessor cooling and b) the dynamics of foams in lubricants. The novel numerical techniques will resolve key issues of available numerical methods and enable the DNS of interfacial transport mechanisms at microscale in a rational computational framework. The capability to directly simulate two-phase flows at microscale will not only increase our fundamental understanding of the complex physics governing interfacial transport mechanisms at microscale, but will also enable engineers to build better devices and systems that rely on such flows. Through the study of the prototypical applications, the proposed research will provide a detailed understanding of interfacial transport mechanisms at microscale, relevant to microfluidic two-phase flows in general and will directly contribute to the development of cooling systems that are capable of handling the heat generated by the next generation of microprocessors and the development of more reliable, efficient and economically friendly lubricants.