Liquid jet formation through the interactions of a laser-induced bubble and a gas bubble

Bing Han,Liu Liu,Xiao-Wu Ni,Xiong-Tao Zhao

doi:10.1063/1.5000086

Abstract

The mechanisms of the liquid jet formation from the interaction of the laser-induced and gas bubble pair are investigated and compared with the jet formation from the interaction of the laser-induced anti-phase bubble pair. The strobe photography experimental method and numerical simulations are implemented to obtain the parameter space of the optimum liquid jet, i.e. highest speed and lowest diameter. It is found that due to the enhanced “catapult effect”, which is induced by the protrusion of the first bubble into the second bubble and the flip back of the elongated part of the first bubble, the optimum liquid jet of the second bubble of the laser-induced anti-phase bubble pair compared to that of the laser-induced and gas bubble pair is 54 %, 65 % and 11 % faster in speed, and 4 %, 44 % and 64 % smaller in diameter, for the 500 μm, 50 μm and 5 μm sized bubbles, respectively. The optimum dimensionless distance for the optimum jet of the laser-induced and the gas bubble is around 0.7, when the maximum bubble radius increases from ∼ 5μm to ∼500 μm, which is different from the laser-induced anti-phase bubble pairs. Besides, the optimum jet of the laser-induced bubble appeared when the bubbles are equal sized, while that of the gas bubble is independent of the relative bubble size, i.e. the liquid jet of the gas bubble has higher robustness in real liquid jet assisted applications when the laser-induced bubble size varies. However, the jet of bubble 2 could maintain a high speed (20 m/s - 35 m/s) and a low diameter (∼5 % of the maximum bubble diameter) over a big range of the dimensionless distance (0.6 - 0.9) for both of the 50 μm and 500 μm sized laser-induced equal sized anti-phase bubble pairs.

Highlights

Be able to result from the external pressure gradient, the external relative liquid velocity and the proximity to a rigid wall.[21]
It has been found that for bubbles generated at the same time, i.e. τ = 0, a liquid jet could be originated from the smaller bubble and penetrate the bigger bubble when 0.64 < γ < 0.78 and 0.74 < ρ < 0.82.32 Studies of an unequal sized bubbles with τ = 0 show that annular jet that leads to the bubble splitting occurs only when ρ ≤ 0.5.34 The controllable liquid jet is a promising tool for micro-injections of living cells, or a micro-pump for directional transport of target samples in micro-fluidic systems
The pressure in bubble 1 is lower than that of bubble 2 during the early stage of the piercing process. These features of the laser-induced anti-phase bubble pairs enlightened the study of the influences of ρ and γ on the jet formation from the interaction of a laser-induced bubble and a steady gas bubble with the maximum radius of ∼5 μm, ∼ 50 μm and ∼ 500 μm in this work

Summary

Introduction

Be able to result from the external pressure gradient, the external relative liquid velocity and the proximity to a rigid wall.[21]. It has been found that for bubbles generated at the same time, i.e. τ = 0, a liquid jet could be originated from the smaller bubble and penetrate the bigger bubble when 0.64 < γ < 0.78 and 0.74 < ρ < 0.82.32 Studies of an unequal sized bubbles with τ = 0 show that annular jet that leads to the bubble splitting occurs only when ρ ≤ 0.5.34 The controllable liquid jet is a promising tool for micro-injections of living cells, or a micro-pump for directional transport of target samples in micro-fluidic systems In this way, the laser energy can be transformed into the directional mechanical force through bubble interactions. The pressure in bubble 1 is lower than that of bubble 2 during the early stage of the piercing process These features of the laser-induced anti-phase bubble pairs enlightened the study of the influences of ρ and γ on the jet formation from the interaction of a laser-induced bubble and a steady gas bubble with the maximum radius of ∼5 μm, ∼ 50 μm and ∼ 500 μm in this work. The numerical method has been proved to be able to handle the big distortion and rupture of the materials during the collapsing of the bubble, especially the whole process of the jet penetrating the bubbles.[30,32]

Methods

Results

Conclusion