低圧気体中で平板に接近する球に作用する抗力

概要

論文の詳細を見る
The resistance force of a sphere moving through air towards a plane surface is associated with the mechanism of particle deposition. In the continuous fluid, the resistance force increases infinitely near the plane surface. However, there has been no investigation on the effect of discontinuous fluid, for instance, air for fine particles whose diameters are as small as several micrometers. In air, the resistance force of the fine particles near the surface does not seem to increase infinitely and thus fine particles would be deposited more easily. It was extremely difficult to measure the resistance force of fine particles directly, so we measured the resistance force of a 6.3 mm foamed styrene ball under reduced pressure. At 10 Pa, the mean free path of air is 670 μm and the Knudsen number of the styrene ball is equivalent to that of a 0.6μm particle in the atmospheric air. The experimental data show that the increment of the resistance force acting on a 6.3 mm sphere near the solid wall under reduced pressure decreases with decreasing air pressure. Hence, it would be concluded that the resistance force of the fine particles near the solid wall in the air is much less than that acting in the continuous fluid.
一般社団法人日本機械学会の論文
1993-05-25