实验研究了矩形液池中蒸发薄液层中蒸发效应与热毛细对流的耦合机理.对于单纯的热毛细对流稳定性从实验和理论上已有深入研究,但目前国际上对带有蒸发界面的热毛细对流问题尚缺乏研究.特别是近来的研究发现,气液界面的蒸发对热毛细对流稳定性有很大的影响.本实验以温度为主要控制参数,测量了不同工况下蒸发界面不同点的蒸发速率和表层温度,并利用PIV方法分析得到了液体内的流场分布.实验结果发现,随着沿界面的温差增加,蒸发液体内的流型从稳定的单涡胞结构变为稳定的多涡胞结构,并最终演变为紊流结构.综合分析以上测量结果并与理论分析结果进行了比较.

液体润滑普遍存在于大多数空间运动部件中.然而,由于空间环境恶劣(低重力、高真空)所造成的润滑剂严重损失,许多液体润滑运动部件都不能达到其使用寿命的要求.因此,有必要采取措施对空间运动部件进行补油,利用多孔储油器补油便是其中的方法之一.由于其体积小、结构简单而广泛应用于小型航天仪器中,并在维持轴承腔内油膜厚度和油分布方面也能取得令人满意的效果,因此备受关注.离心作用和加热效应是使储油器溢油的两种方法,本文针对这两种方法,对空间多孔储油器的液体润滑剂储运规律进行理论分析,同时设计了离心供油和加热供油两套实验装置.

The effects of liquid evaporation on the interfacial tension-induced convection and instability are studied theoretically and experimentally in present paper. The main purpose of this investigation is to understand the mechanism of convection instability in a thin vapor-liquid layer with a mass exchange surface (interface) where exists the coupling of evaporation phenomenon and Marangoni-Bénard instability. A systematic model of two-layer system consisting of the evaporating liquid layer and vapor-phase layer, heated from below, is studied by linear instability analysis. The thickness of both layers is finite and each layer has an infinite extension in length. The top wall is assumed as a porous medium pervious to vapor, through which the gas phase is passed in a certain velocity in order to control the evaporation flux and vapor pressure. Deformable vapor-liquid interface in the perturbation state are considered, and the influence on the convection instability of the system are analyzed comparatively. Neutral stability curves of the two-layer system are presented for different cases, such as evaporation coefficient, evaporating mass flux, gravity, etc.