Multifactorial Analysis of the Collapse Process of Double Bubbles Based on the Coarse-Grained Force Field in Free Domain

Cavitation has been a hot research topic for scholars in various fields because of the intense mechanical, chemical, and thermal effects of bubble collapse. It forms a cluster of bubbles, and the bubbles will affect, interfere with, and couple with each other. To grasp the main factors affecting bubble collapse and the interbubble mechanism, the paper adopts the molecular dynamics simulation combined with the coarse-grained force field to study the collapse process of the double bubble model and takes the dynamic shape change of the bubbles, the local velocity distribution, and the local pressure distribution as the object to summarize the position angle, the shock velocity, and the bubble distance on the collapse law and the primary and secondary influence relationship and then reveals the interbubble mechanism. The results show that with the increase of the position angle, the collapse velocity of the right side of bubble A gradually decreases compared with the left side, while bubble B has the opposite characteristics. When the angle is 0°, bubble A and bubble B collapse at the same time and the direction of the jet is the same as the shock direction. With the increase of the position angle, the direction of the jet is biased toward bubble B. The collapse time of bubble B gradually increases with the increase in the bubble distance. Taking the collapse time as the evaluation standard, the relationship between the three factors is shock velocity (u) > position angle (θ) > bubble distance (L). In this paper, it perfects the cavitation theory and provides technical support for the efficient application of hydrodynamic cavitation technology.