Development of a vacuum pump without a moving part with the aid of thermal transpiration flow of a rarefied gas

我们提出的课题从以下两个方面进行研究。本文对稀薄气体中温度场诱导的流动进行了全面的研究，以期找到利用温度场诱导的流动构造无运动部件泵的可能性。(1)首次在实验上观察到均匀加热板边缘诱导流动。(2)基于动力学理论，在Knudsen数全范围内对不同温度的同轴椭圆圆柱间的流动进行了数值研究。除了克努森数较小的情况外，发现流动的结构受到系统整体几何形状的很大影响。(3)对周期性温度分布和周期性挖沟的圆管内的单向流动进行了详细的数值研究。发现泵送效应比通道流的效应大几倍……Sone等人先前的研究更多。(4)实验观察到，在没有平均压力和温度梯度的管道中诱导单向流动，如(3)。实验表明，管道的形状对诱导单向流至关重要。(5)所得结果与我们以前的研究结果相结合，形成了对温度场引起的流动的系统调查。这些研究表明，利用热蒸腾技术实现无运动部件的泵送系统并不困难。(1)在动力学理论的基础上，对球形凝聚相的弱蒸发或弱凝结进行了分析和数值研究，并在整个Knudsen数范围内阐明了流动的详细行为。进一步，Onsager的关系被证明对任意Knudsen数都成立。(2)对平面凝聚相上的跨音速凝聚流动进行了解析研究。阐明了解的解析结构，特别是解在声速点上存在范围的不连续变化。(3)详细研究了两轴向圆柱凝聚相之间的圆柱Couette流动。发现了新型分岔的存在，并阐明了分岔发生的参数范围及其物理机制等。少

The subject that we proposed is studied in the following two directions.1. Flows induced in a rarefied gas by its temperature fieldThe comprehensive study of flows induced by temperature fields is made in order to find the possibility of constructing a pump without any moving part with the aid of the flow.(1) It is experimentally observed for the first time that a flow is induced around the edge of a uniformly heated plate.(2) Flows induced between two coaxial elliptic cylinders with different temperatures are studied numerically on the basis of kinetic theory for the whole range of the Knudsen number. The configuration of the flow is found to be considerably affected by the global geometry of the system except in the case of small Knudsen numbers.(3) One-way flows induced in a circular pipe with a periodic temperature distribution and with ditches periodically dug are studied numerically in details. The pumping effect is found to be several times larger than that of the channel flows … More studied previously by Sone et al.(4) It is experimentally observed that a one-way flow is induced in a pipe without average pressure and temperature gradients, as in item (3). The experiment shows that the shape of the pipe is essential to inducing a one-way flow.(5) The results obtained, combined with those of our previous research, are formed into a systematic survey of flows induced by temperature fields.These studies show that a pumping system without a moving part is not difficult to be realized with the aid of the thermal transpiration.2. Flows with evaporation or condensation in relation to a cryo-pumping system(1) Weak evaporation from or condensation onto a spherical condensed phase are studied analytically and numerically on the basis of kinetic theory, and the detailed behavior of the flow is clarified for the whole range of the Knudsen number. Further, Onsager's relation is shown to hold for arbitrary Knudsen numbers.(2) Transonic condensing flows onto a plane condensed phase are studied analytically. The analytic structure of the solution, especially, the discontinuous change of the range of existence of a solution across the sonic point is clarified.(3) Cylindrical Couette flows between two axial circular cylindrical condensed phases are studied in details. New type of bifurcation is found to exist, and the range of the parameters where the bifurcation takes place and its physical mechanism etc. are clarified. Less