蒸发毛细弯液面稳定性对毛细抽吸换热装置的运行有着重要意义。由于弯液面的蒸发80%是发生在一个微小的区域,即薄膜区,因此可以预期,不稳定性将最先产生于这一区域。薄膜区的界面会受到多种作用力的影响,例如脱离压力,蒸发质量损失,蒸气反冲以及温度梯度引起的热毛细作用,其机理相当复杂。本文对处于蒸发状态下的非等温弯液面薄膜区进行线性稳定分析,并通过施加小扰动于界面演化方程,获得了蒸发弯液面固有稳定性判定准则。该准则仅取决于毛细管弯液面温度、工质热物性以及毛细管几何尺寸,对毛细抽吸换热装置的应用有很好的实际指导意义。
The stability of evaporating capillary meniscus is crucially important for the operation of capillary pumped heat transfer devices.Since 80% of the mass transfer by evaporation occurs on a very small region,so-called thin film region,it is expected that the instability will arise from this region.In this region,the interface of the liquid film is dominated by several factors such as disjoining pressure,mass loss by evaporation,vapor recoil and thermal capillary stress.Therefore,the real physical mechanism is highly complex.Present work focuses on establishing an intrinsic stability criterion through the linear stability analysis for the thin film region of an evaporating meniscus by disturbing its interface evolution equation with a small perturbation.It is found that this criterion depends on temperature of the meniscus,thermophysical properties of the working fluid and dimensions of the capillary tube.This linear stability criterion can be used as a practical tool in design and analysis of the capillary pumped heat transfer devices.