Numerical investigation on laser-induced nanobubble nucleation and dynamics of plasmonic nanoparticles with different structures

Abstract

The motion and heat transfer understanding of laser-induced nanobubbles generating on nanoparticles is important for solar energy utilization, medical treatment and seawater purification. Phase change lattice boltzmann method is used to simulate heat and mass transfer between liquid and vaper and momentum exchange method is used to study the nanoparticle trajectory in the fluid. Convection between the nanoparticle surface and the surrounding fluid is considered using a novel conjugated thermal boundary approach, which involves the integration of two meshes and virtual nodes. Solid and hollow nanoparticles with and without pillars are investigated to evaluate their performance in generating nanobubbles. Both the surface to vloume ratio and the absorption coefficient affect the nanobubble generation threshold under normal gravity. The hyper gravity promotes the nanobubble nucleation when nanoparticle size is more than 20 nm. Nanobubbles nucleate easily on nanoparticle with short pillar. Although hollow nanoparticles have the lower threshold for nanobubble generation, the nanobubble generating on hollow nanoparticles is less than on solid nanoparticles. The highly aggregated nanoparticles enhance the innitial nanobubble generation. However, nanoparticles with longer spacing produce more nanobubble in long term.