具有复杂几何特征的蒸发液滴群中的多尺度传热传质机理研究

基于微液滴蒸发的冷却技术由于其高传热系数和低泵压需求逐渐成为了缓解电子器件发热问题的有效途径。目前液滴蒸发的研究较少考虑三相接触线上的薄膜区域和固-液-气界面上的热质交换特征，且通常只关注球冠形状的单液滴蒸发现象。本项目拟以钉扎在复杂微柱结构上的液滴群为研究对象，对具有复杂几何特征的液滴群在蒸发过程中的多尺度热质输运机理进行基础科学研究。通过分析多液滴蒸发中热流密度、对流场及浓度梯度等关键物理量在液滴不同区域的分布特征和变化规律，揭示界面传递、分离压及热毛细对流等不同尺度的传递机制对液滴集群蒸发的共同影响，建立准确描述多液滴蒸发的多尺度热质输运模型。具体内容包括：液滴蒸发中的界面热质传递行为及薄液膜区域的流动和传热特征；非球冠形复杂液滴内的多尺度传热传质现象和主导机理；多液滴群中的协同蒸发换热特征。

Microdroplet evaporation has shown great potential in addressing the thermal issue due to its high heat transfer coefficient and the low pumping power required in the fluid delivery system. However, the effect of thermal transport across the solid-liquid and liquid-vapor boundaries and within the thin film region have only received limited attention when analyzing droplet evaporation. In addition, a majority of studies only focused on the evaporation behavior of a single droplet with a capped spherical geometry. In this proposal, we seek to investigate the multiscale heat and mass transport characteristics of an array of evaporating microdroplets with complex geometries pinned on micropillar structures. By analyzing the distribution pattern of heat flux, flow field, and concentration gradient in different regions of evaporating droplet, the proposed research will reveal how the evaporation behavior of an array of microdroplet is affected comprehensively by the transport mechanisms at different scales. The detailed tasked involved in this research proposal include: (1) analysis of thermal transport behavior across the solid-liquid and liquid-vapor interface and within the thin film region; (2) investigation of the dominating heat and mass transfer mode in non-spherical droplet with a complex geometry; (3) analysis of the competitive and cooperative effect in the evaporative transport of an array of droplets.