Abstract
This study investigates the effect of ambient pressure on ignition delay for B/KNO3 using laser ignition. Experiments were conducted in air with ambient pressure as a parameter, and the influence of the generated gas was examined by comparing vertical and horizontal laser irradiation. The results showed that in vertical irradiation, ignition delay increases as ambient pressure rises. This is because the generated gas interferes with the laser, and the gas density increases with pressure, reducing laser intensity and heat transfer to the ignition charge. At lower pressures, gas density decreases due to diffusion, leading to less laser attenuation and shorter ignition delays. In horizontal irradiation, the range of the ignition delay range with respect to the ambient pressure is much smaller than that of vertical irradiation. The generated gas moves upward due to buoyancy, reducing interference between the gas and the laser. These findings indicate that ambient pressure significantly affects ignition delay by influencing gas generation and laser attenuation.
