非定常加熱時の低熱流束膜沸騰遷移に関する研究 : 第2報, 伝熱面材料,性状の気泡挙動に与える影響

抄録

The effects of wall material and surface condition on the behavior of an initial boiling bubble of R113 subjected to transient heating is investigated using a heater with a large heat capacity. The behavior of the initial bubble is closely related to the premature transition to film boiling of liquids with high wettability. An initial bubble, which is peculiarly shaped like a 'straw hat' and leads to premature transition in saturated liquid nitrogen as reported in a previous report, appears also on the heated wall with large heat capacity and grows rapidly to cover the entire wall surface. The initial bubble is found to be a coalesced bubble into which small bubbles activated in succession along the heated surface are rolled, from the observation using a high-speed video camera. The growth rate of the initial bubble along the heated surface is not greatly affected by the thermal conductivity of wall material but is affected markedly by the surface roughness.