Microscale Heat Transfer in Digital Microfluidics

CBET-1403828Mohseni热量是电子设备正常运行时不可避免的副产品，是在电路活动过程中将电能转换为热能而产生的。电子系统速度的提高通常是通过由于更高的电路封装密度而减少电路延迟来实现的。不幸的是，这伴随着每个电路的功耗增加。随着对快速电子设备的需求的增加，对有效和高效地去除热通量的能力的需求也越来越大。为此，从非常小的区域安全地散失大量热量的能力是当今许多尖端技术的关键。目前，在高性能超级计算机、电力电子器件、电动汽车、先进军用航空电子设备、雷达和激光中，热流密度降低了100-1000W/cm2甚至更多。这项拟议的研究将探索液滴的主动和按需微驱动和传输，这是一种称为数字化热传递(DHT)的过程，用于高功率紧凑型系统的有效热管理。分布式哈希表技术有两个主要优点。首先，与连续的液体冷却流动和空气冷却系统相比，使用单个液滴并随后在液滴内引入回流区可以提高散热率。其次，可以离散地操纵液滴，使其能够单独地、基于指令的流体处理编程，其中液滴在分组中被运输、混合、反应、存储和分析，而不需要移动机械部件。DHT的这一能力非常适合于瞬时热管理和抑制功率尖峰消散期间的温度过冲。除了上面预期的热科学、流体力学和计算技术方面的技术进步外，本科生和研究生将接受这些主题的培训。本科生研究助理将通过补充的REU支持来寻找，可以预期来自前面提到的领域。PI打算在佛罗里达大学开发一门关于微尺度运输的课程，并通过增加制造和计算组件来扩展他目前关于微米和纳米热流体学的课程。PI现有的多学科课程将丰富这项工作的成果，扩大学生接触微流体学的不同方面。

CBET-1403828MohseniHeat is an unavoidable byproduct of the normal operation of an electronic device, generated as a result of electrical energy being converted to thermal energy during circuit activities. An increase in speed of an electronic system is often achieved by reduction in circuit delay due to higher circuit packaging densities. Unfortunately, this is accompanied by increased power dissipation per circuit. As the need for fast electronic devices increases, the ability to remove heat flux effectively and efficiently is in greater demand. To this end, the ability to safely dissipate large amounts of heat from very small areas is key to many of today's cutting edge technologies. Reducing heat fluxes by an order of 100-1000 W/cm2 and beyond is currently encountered in high performance supercomputers, power electronic devices, electric vehicles, advanced military avionics, radars, and lasers. The proposed investigation will explore the active and on-demand micro actuation and transport of liquid droplets, a process termed Digitized Heat Transfer (DHT), for effective thermal management of high-power compact systems. The DHT technique has two main advantages. First, the use of individual droplets and the subsequent introduction of recirculation zones inside the droplets allows for an increased heat removal rate as compared to continuous liquid-cooling flows as well as air-cooling systems. Second, the droplets may be discretely manipulated, enabling it individual, instruction-based programming of fluid processing, where droplets are transported, mixed, reacted, stored, and analyzed in packets without the need for moving mechanical parts. This capability of DHT is aptly-suited for transient thermal management and the suppression of temperature overshoots during the dissipation of power spikes.In addition to the technical advances in thermal sciences, fluid dynamics, and computational techniques anticipated above, undergraduate and graduate students will be trained in these topics. Undergraduate research assistants will be sought via supplementary REU support, and can be expected to come from the previously mentioned fields. The PI intends to develop a course in micro-scale transport at the University of Florida and expand his current course on micro and nano thermofluidics with the addition of both a fabrication and a computational component. The PI's existing multidisciplinary courses will be enriched with results from this work, expanding student exposure to different aspects of micro fluidics.