Suspended liquid particle disturbance on laser-induced blast wave and low density distribution

Abstract

Abstract:9The impurity effect of suspended liquid particles on laser-induced gas breakdown was 10 experimentally investigated in quiescent gas. The focus of this study is the investigation of the 11 influence of the impurities on the shock wave structure as well as the low density distribution. A 532 12 nm Nd: YAG laser beam with 188 mJ/pulse was focused in the chamber filled with suspended liquid 13 particles 0.9 ± 0.63 μm in diameter. Several shock waves are generated by multiple gas breakdowns 14 along the beam path in the breakdown with particles. Four types of shock wave structures can be 15 observed: 1) the dual blast waves with similar shock radius, 2) the dual blast waves with large shock 16 radius at the lower breakdown, 3) the dual blast waves with large shock radius at the upper breakdown, 17 4) the triple blast waves. The independent blast waves interact with each other and enhance the shock 18 strength behind the shock front in the lateral direction. The triple blast waves lead to the strongest 19 shock wave in all cases. The shock wave front that propagates towards the opposite laser focal spot 20 impinges on one another, and thereafter a transmitted shock wave (TSW) appears. The TSW interacts 21 with the low density core called a kernel, the kernel then longitudinally expands quickly due to a 22Richtmyer-Meshkov like instability. Laser-particle interaction causes an increase in the kernel volume 23which is approximately five times as large as that in gas breakdown without particles. In addition, 24 laser-particles interaction can improve the laser energy efficiency. 25Keywords: Laser-induced gas breakdown; Suspended liquid particles; Impurity effect; Hot 26 plume 27 2

Lightning under water: Diverse reactive environments and evidence of synergistic effects for material treatment and activation

“…In contrast, in the fourth (triple) type of breakdown, the breakdown is associated with one additional blast wave. 135…”

High velocity infrared thermography and numerical trajectories of solid particles in compressible gas flow

“…Pasandideh-Fard et al [12]), laser energy deposition techniques (Ukai et al [13]), pulverized coal furnaces (Chen et al [14]) and solid propellant rockets (Lomba et al [15]; Najjar [16]). Last but not least, also convectively unstable fluids transporting fine dispersed particles should be considered as instances pertaining to this subject (Lappa [17]), e.g., rising plumes originating from urban mass fires, the release in the atmosphere of smokes from industrial stacks (McGrattan et al [18]), severe accidents in chemical or nuclear reactors (Kissane [19]), and pyroclastic flows from volcanic eruptions (Valentine and Wohletz [20]; Haszpra and Tél [21]).…”