One-way-coupling simulation of cavitation accompanied by high-speed droplet impact
| Autor: | Keita Ando, Tomoki Kondo |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Fluid Flow and Transfer Processes
Physics Tension (physics) Mechanical Engineering Bubble Computational Mechanics Nucleation Mechanics Condensed Matter Physics 01 natural sciences 010305 fluids & plasmas Physics::Fluid Dynamics Classical mechanics Mechanics of Materials Cavitation Phase (matter) 0103 physical sciences Erosion Coupling (piping) Two-phase flow 010306 general physics |
| Zdroj: | Physics of Fluids. 28:033303 |
| ISSN: | 1089-7666 1070-6631 |
| Popis: | Erosion due to high-speed droplet impact is a crucial issue in industrial applications. The erosion is caused by the water-hammer loading on material surfaces and possibly by the reloading from collapsing cavitationbubbles that appear within the droplet. Here, we simulate the dynamics of cavitationbubbles accompanied by high-speed droplet impact against a deformable wall in order to see whether the bubble collapse is violent enough to give rise to cavitationerosion on the wall. The evolution of pressurewaves in a single water (or gelatin) droplet to collide with a deformable wall at speed up to 110 m/s is inferred from simulations of multicomponent Euler flow where phase changes are not permitted. Then, we examine the dynamics of cavitationbubbles nucleated from micron/submicron-sized gas bubble nuclei that are supposed to exist inside the droplet. For simplicity, we perform Rayleigh–Plesset-type calculations in a one-way-coupling manner, namely, the bubbledynamics are determined according to the pressure variation obtained from the Euler flow simulation. In the simulation, the preexisting bubble nuclei whose size is either micron or submicron show large growth to submillimeters because tension inside the droplet is obtained through interaction of the pressurewaves and the droplet interface; this supports the possibility of having cavitation due to the droplet impact. It is also found, in particular, for the case of cavitation arising from very small nuclei such as nanobubbles, that radiated pressure from the cavitationbubble collapse can overwhelm the water-hammer pressure directly created by the impact. Hence, cavitation may need to be accounted for when it comes to discussing erosion in the droplet impact problem. |
| Databáze: | OpenAIRE |
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