Abstract: | An experimental study was conducted to investigate transient local heat transfer around a bubble at onset of boiling on a thin glass heating plate immersed in saturated n-hexane at low pressure. Eight rapid response Cu-Ni thermocouples consisting of a vacuum deposited thin film were used to measure the temperature change of the heating surface. Simultaneous high-speed video photographs were also obtained. The surface temperatures near a nucleation site decreased rapidly owing to the evaporation of a thin layer (microlayer) of liquid formed beneath the bubble in the early period and the rate of bubble growth increased with increasing incipient boiling superheat (ΔTIB). The thickness of the microlayer decreased markedly with increasing ΔTIB. © 1998 Scripta Technica, Heat Trans Jpn Res, 26(7): 484–492, 1997 |