Quantitative Visualization and Trajectory Measurement of Single Bubble Dynamics Induced by Controlled Negative Pressure

Abstract

Abstract. This research investigates the formation and dynamic behavior of a single gas bubble in de-ionized water subjected to negative pressure conditions (gauge pressure). Based on this framework, a systematic investigation was conducted to examine the influence of the intake pipe's inner diameter, liquid level height, and gas space volume on bubble formation and ascent dynamics. Experimental findings indicate that the bubble generation process can be divided into two distinct phases: a growth phase and a detachment phase. The size at detachment and the subsequent motion characteristics are governed by multiple factors, among which the intake pipe's inner diameter has the most pronounced effect. Specifically, an increase in pipe diameter corresponds to a significant enlargement in both the bubble detachment diameter and equivalent diameter, accompanied by intensified interface deformation and more pronounced fluctuations in the rising trajectory. Conversely, under conditions of smaller pipe diameters, bubbles tend to be smaller, and exhibit more stable motion. Increasing the liquid level height results in greater static pressure on the bubble, thereby extending the growth duration, augmenting the detachment, and equivalent diameters, and amplifying motion fluctuations during the ascent phase. An increase in gas space volume prolongs the duration of negative pressure extraction, enabling the bubble to accumulate more gas prior to detachment, which leads to a modest increase in detachment size; however, its impact on trajectory, velocity, and deformation during the rising phase remains comparatively limited. The research findings elucidate the fundamental dynamic mechanisms governing bubble evolution under conditions of negative pressure, providing novel experimental evidence that advances the understanding of bubble formation and motion in such environments.