2014年引智讲坛之二十九

题目：多相流在微通道内的流动

时间：2014年12月15日（星期一）上午10：00—11：30

地点：理科教学南楼215

主要内容：

（1）南洋理工大学机械与宇航工程学院教学科研简介；

（2）微通道下的连续多相流动研究，含微通道制备，两相流动的界面预测，外场对微通道内两相流动的影响，两相界面的控制，其中相微滴的形成与尺度控制等。

2014年引智讲坛之三十

题目：高能电子芯片的喷淋冷却

时间：2014年12月16日（星期二）下午2：00—3：30

地点：理科教学南楼215

主讲人简介：

王德能教授（Wong Teck Neng,mtnwong@ntu.edu.sg），南洋理工大学机械与宇航工程学院教授（School of Mechanical and Aerospace Engineering,Nanyang Technological University），国际知名多相流与传热技术研究专家。

Wong教授的主要研究领域为两相流与传热，微通道内多相流，微流装置内的多流体电渗流等，承担了国防科学国家实验室、国防部、教育部、新加坡科学院等部门立项的多项课题研究，在International Journal of Heat and Mass Transfer, International Journal of Refrigeration, Microfluidics and Nanofluidics, Chemical Engineering Science等期刊上发表论文96篇，专利2项。

主要内容：

（1）南洋理工大学机械与宇航工程学院研究生招生政策；

（2）喷淋冷却模型构建，喷淋冷却实验装置研制，喷淋冷却实验结果及其分析，喷淋冷却参数优化等。

讲座内容英文摘要：

1. Continuous and droplets-based Microfluidics

Microfluidics refers to the science of designing, fabricating and formulating devices and processes that manipulate the fluid flows with a length scale in the order of hundreds of microns. As the geometry changes from macroscale to microscale, the volume to surface area ratio increases dramatically. Many considerations have to be made because the factors not affecting the fluid on the macroscale has become increasingly important in influencing the characteristic and the mechanism in microscale. These include the surface tension and electric double layer. This presentation covers two aspect of multiphase flow in microfluidics: (a) Continuous multiple flow streams, (b) Droplets-based microfluidics

(a) Continuous mutiphase micro-fluidics:

The interfaces between the multiple flow streams are often known as the Laminar Fluid Diffusion Interfaces (LFDI). In this presentation, we propose theoretical models to predict the interface position of two-liquid flowing through a rectangular cross section microchannel. In experiment, we will show that by adjusting the applied electric field of the conducting liquid, the interface position can be precisely controlled.

Droplets- based micro-fluidics:

(b) The flow characterize the droplet formation, the concept of manipulation of droplets splitting, sorting and mixing will be discussed. Some results on the CFD simulation will be presented.

2.Experimental and Theoretical Studies of Spray Cooling for High Power Electronics

Spraycooling as a promising thermal management scheme has received much attention from modern industrial and technological applications, such as power electronics, nuclear power generation and high-power conversion systems. This presentation focuses on the experimental and theoretical investigations of spray cooling and its applications to high power electronics.

Fundamentalstudies of the spray characteristics and spray structures of pressure swirl nozzles in free spray atomisation and in spray cooling were carried out using Phase Doppler anemometry (PDA). The experiments show that the spray characteristics and spray structure varies as the axial distance increases. A strong thermal effect on the spray of pressure swirl nozzle was observed in the spray cooling process.Heat transfer experiment was performed to analyse the effects of spray characteristics on the heat transfer performance. Theoretical models are developed to investigate the heat transfer in the non-boiling and boiling regimes of spray cooling based on the obtained spray characteristics.

The experimental results show a promising prospect of using multi-nozzle arrays on large area power electronics cooling. Furthermore, the effects of differently scaled structure surfaces on the spray cooling performance are investigated on a small surface with high heat fluxes in a closed-loop system

注：王教授在广州交流期间为：12.14—12.27，如果有在传热、多相流等研究上有需要交流的老师和学生，均可联系相互研讨。

联系人：机电学院江帆，电话：13828471796，邮箱：jiangfan2008@126.com。