気泡微細化沸騰における気泡の挙動

抄録

High heat flux far exceeding CHF is accomplished in micro bubble emission boiling (MEB) which appears in transition boiling region under some condition of liquid subcooling and velocity. It is necessary for discussion of heat transfer mechanism in MEB to understand how the liquid is supplied to the heated surface, which should be achieved by sincere observation of bubble motion on the surface. In this study bubble height and diameter are measured from high speed film and analyzed for S-MEB I occurring on a horizontal surface in parallel flow of water. The bubbles collapse against the surface with high collapsing rate. The collapsing rate that is the decreasing rate of the bubble height increases with increasing of the heat flux. This collapsing motion is supposed to carry the liquid to the surface like a micro jet in cavitation. As a result of the analysis using an equivalent bubble radius, the radius tends to decrease along the curve of the Rayleigh solution, which means bubbles collapse under inertia control rather than heat transfer control, ill high heat flux region of S-MEB I.