傾斜平板上の液滴の転落機構 : 液滴の転落体積(熱工学,内燃機関,動力など)

Abstract

The critical volume at which liquid droplets start to slide on an inclined plate was investigated. The critical volume was theoretically estimated based on the energy minimum condition when the droplets expand on the inclined plate. In order to calculate the system energy, the three-dimensional configuration of droplet was obtained from the approximate Laplace equation based on the assumption that the three-phase contact line is ellipse. The width of ellipse was determined when the energy takes minimum and the critical volume was obtained from the critical condition, i.e., the force balance between the surface tension and the gravitational force acting on the droplet. The critical volumes were experimentally measured for each combination between two kinds of test liquids and three kinds of solid plates. The movement of three-phase contact line was carefully observed when the volume of droplet was slowly increased on the plates with the designated inclination angles. The critical volumes were determined when the continuous movement of contact line is observed with the velocity more than 0.04mm/min. The measured critical volumes for each experimental condition fairly agree with theoretical ones within 10% deviation.