Fluid Flow and Heat and Mass Transfer in Micro-systems with Complex Physics

微器件中的流体流动和传热传质在环境、工业、生物和生物医学系统的利用、检测、传感、监测和诊断中具有许多工程应用。有一个廉价的，可靠的，实时的设备，以诊断疾病，监测环境有害气体，检测生物和化学战剂等，目前的建议的重点将是在微流体系统中的流动和液滴的物理研究。需要开发数学模型和模拟工具。新创建的知识导致更好地理解液滴微型设备的操作，改进新型诊断设备的设计，如流动聚焦和数字液滴设备，并开发新技术。从长远来看，它旨在扩大我们的成果，开发工业和环境监测设备。* 微流体和纳米流体装置已成为诊断疾病的有效工具。已经对具有不同几何配置的用于广泛应用的不同类型的微流体装置进行了广泛的研究。然而，大多数工作都是通过试验和错误来优化这些设备的操作。流动是层流，其中混合过程主要由缓慢扩散机制控制。流体流动也是具有液滴的两相或多相。混合过程通常通过施加外力进行，例如电、热、磁或声学。两相或多相和/或多组分流动的主题在计算上是一个非常具有挑战性的任务。大多数分析都是基于经验相关性和非精确科学。此外，微观和纳米尺度上的流体-结构相互作用还没有完全理解。这个问题变得更具挑战性的额外的物理，如电力，焦耳加热，不稳定的流动等，因此，有必要了解和发展坚实的基础物理的问题，并开发一个数学模型，这些设备的模拟。仿真结果有助于我们理解物理和控制参数的影响。此外，仿真在这种设备的优化过程中是成本有效的。传统的CFD方法在处理多相流时有许多局限性。另一方面，格子玻尔兹曼方法（LBM）是一种非常强大的替代方法相比，传统的方法来解决流体动力学问题。在LBM中，将热力学与输运方程结合起来相对容易。此外，它享有简单的编码，可以很容易地与并行处理器计算机使用。这项研究的成果将有助于为许多应用开发新颖、可靠和实时的基于液滴的微流体设备。这些成果将有助于加拿大经济。

Fluid flow and heat and mass transfers in micro devices have many engineering applications in utilizing, detecting, sensing, monitoring, and diagnosis of environmental, industrial, biological, and biomedical systems. There is a need for cheap, reliable, real-time devices to diagnose diseases, monitor environmentally harmful gases, detect biological and chemical warfare agents, etc. The focus of the current proposal will be on investigating the physics of flow and droplets in microfluidic systems. Mathematical models and simulation tools need to be developed. The newly created knowledge leads to better understanding the operation of droplet micro devices, improve the design of novel diagnostic devices, such as flow focusing and digital droplet devices, and in developing a new technology. In the long term, it is intended to expand our results for developing industrial and environmental monitoring devices. ***Microfluidic and Nanofluidic devices have emerged as potent instruments for diagnosis of diseases. Extensive research has been done on different types of microfluidic devices for a wide spectrum of applications with different geometrical configurations. However, most of the works are done by a trial and error to optimize the operation in those devices. The flow is laminar, where the mixing process is mainly controlled by a slow diffusion mechanism. The fluid flow is also in two or multi-phases with droplets. The mixing processes are usually carried out by an applied external force, such as electric, thermal, magnetic, or acoustic. The topic of two or multi-phase and/or multicomponent flows is a very challenging task, computationally. Most analysis has been based on empirical correlations and non-exact science. Moreover, the fluid-structure interaction on micro- and nano-scales is not fully understood. The problem becomes more challenging with extra physics, such as electrical force, Joule heating, unsteady flows, etc. Hence, there is a need to understand and develop solid underlying physics of the problem and develop a mathematical model for simulations of those devices.***The simulation results help us to understand the physics and the effects of the controlling parameters. Also, simulation is cost effective in the optimization process of such devices. Conventional CFD methods have many limitations when it comes to dealing with multi-phase flows. On the other hand, the Lattice Boltzmann method (LBM) is a very powerful alternative method compared with the conventional methods to solve fluid dynamics problems. In LBM, it is relatively easy to integrate thermodynamics with transport equations. Besides, it enjoys simple coding and can be easily used with parallel processor computers. The outcome of the research will help in developing novel, reliable and real-time, droplet-based microfluidic devices for many applications. The outcomes will contribute to the Canadian economy.