Laser stimulated downward combustion propagation phenomenon

Abstract

Enhanced energy requirement has necessitated active research efforts to understand combustion behaviour in presence of alternative energy sources. In the last five decades, emphasis on combustion focuses on two aspects viz., improving quality of combustion and addressing the risks/hazards. With recent advancement, an aspect which is researched upon is the combustion behaviour in the presence of laser flow. Their applications pertain to propulsion, energy generation, artillery, fire safety and defence support systems. Laser induced combustion consolidates transmission of high energy with the use of laser, introducing uneven heat stresses and leading to the failure of structural integration. Present work is motivated by the need to have better utilization of combustion engineering and to enhanced fire safety. The scientific investigation is carried out to explore the laser-combustion interaction(s) and identification of significant implications. A simplified experimental setup was upraised and the effect of lasers on combustion propagation was observed on the smoldering regression rate and flame spread rate. Systematic experimentation was carried out for varying external energy source (laser) configurations, separation distance, laser intensity, and presence of lenses. Results highlight that presence of lasers significantly affect the combustion propagation for flaming and smoldering cases. The extent of effect varies with the quantified parametric. The flame spread rate and regression rate exhibits non-monotonous behavior with systematic variation in key controlling parameters signifying the local maximum and minimum changes. As a potential application, this phenomenon can be applied to diverse applications with the unique property of travelling at the speed of light, no complicated trajectory calculations, not being affected by gravity, its invisibility and its ability to take on multiple targets from a stand-off distance.