Numerical simulation of the effects of spraying parameters on the bow shock wave and atomized droplets deposition

Silicon-based nanomaterials can effectively alleviate volume effects and are crucial for improving the capacity performance and cycling performance of existing lithium-ion batteries. Among various methods, cold spray deposition shows great potential in preparing high-performance silicon-based electrodes. However, traditional cold spray technology faces challenges in directly depositing nanopowders. One viable solution is to prepare nanopowders into nanosuspensions, atomize them into micron-sized droplets, and inject them into the nozzle, utilizing the droplets as carriers to achieve silicon nanopowder deposition. Based on this approach, this paper employs numerical simulation to study the effects of gas parameters (pressure, temperature), nozzle structural parameters (throat diameter, exit diameter, expansion ratio, divergent length, injection position and angle), and droplet composition (water content) on bow shock and impact velocity. The results show that the pressure of the driving gas and the geometric parameters of the nozzle will affect the bow shock near the substrate, and further affect the impact velocity of the droplets. Since the droplets is radially injected, there is a “hindering” effect between the powder feeding gas and the driving gas. The pressure of the driving gas not only affects the bow shock, but also affects the trajectory of the droplet movement. While the geometric parameters of the nozzle need to be comprehensively considered to weaken bow shock waves and increase impact velocity. Gas temperature has significant effects on atomized droplets deposition and the solidification and evaporation of droplets will affect droplet acceleration behavior. Droplet composition influences impact velocity primarily through composite density and evaporation behavior of droplets and appropriate droplet component ratios can effectively improve droplet impact velocity.