2125 鉛直加熱流路における蒸気泡の発泡点離脱挙動  [in Japanese] Behavior of a Vapor Bubble after the Detachment from a Nucleation Site in a Vertical Heated Tube  [in Japanese]

The motion of a vapor bubble after the detachment from a nucleation site in a vertical heated tube was visually observed using two high speed video cameras. It was revealed from video images that the bubble rise path after the detachment is significantly affected by the two parameters : liquid flowrate and bubble size. Almost all the bubbles slid along the vertical wall at low liquid flowrate while intermediate sized bubbles lifted-off the wall in the horizontal direction at higher liquid flowrate. The two parameters would hence have important role for the heat transfer rate, condensation rate and the critical heat flux in flow boiling. A simple Lagrangian simulation was also carried out to describe qualitatively the effects of the two parameters.