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

Abstract An experimental investigation was conducted to explore the generation and dynamic behavior of a single gas bubble in deionized water under negative pressure conditions. A systematic analysis examined the effects of intake pipe inner diameter, liquid level height, and gas space volume on bubble growth and movement. Under these conditions, bubbles spontaneously form and detach from a stationary liquid as gas enters the intake pipeline. Research indicates that bubble generation and detachment can be categorized into two distinct stages: expansion and detachment. The balance of forces during these stages was found to critically influence the final size and trajectory of the detached bubbles. The study revealed that bubble deformation in larger diameter pipes is more complex, while smaller diameter pipes produce more stable trajectories with less deformation. A rise in liquid level height enhances the buoyancy and inertial effects, resulting in a larger detachment diameter. Consequently, the complexity of the bubble's movement trajectory also increases. Furthermore, a larger gas space volume extends the duration of negative pressure suction, allowing more gas to accumulate before formation and thereby increasing the final detachment diameter. This study offers theoretical support and an experimental foundation for applying negative pressure-driven bubbles in microfluidics and related engineering fields.