Experimental study of the motion and shape of a Taylor vapor bubble floating in a channel at saturation pressure

The dynamics of the Taylor vapor bubble rise in a circular (16 mm cross-sectional diameter) and annular (25 and 16 mm cross-sectional diameters) channel at saturation pressure was experimentally studied. The bubble formed during boiling of superheated degassed liquid. It was found that the movement velocities of its front and rear surfaces are variable and depend on the rise regime, its position in the channel, and the previous rise dynamics. It is shown that this behavior is determined by the spatiotemporal distribution of liquid temperature at the bubble boundary. Based on the obtained results, a map of rise regimes was plotted, linking the nature of movement with the magnitude of liquid superheating near the vapor bubble surface.