Inter-droplet flame propagation characteristics revealed in microgravity spray combustion research

Study on the microscopic mechanism of flame propagation in spray is essential to understand the mechanisms of spray flame holding and group combustion onset, which are most important spray combustion characteristics of practical interest. However, this phenomenon is not easy to observe in conventional laboratory experiments. Recent Japanese micro-gravity spray combustion researches have provided a lot of new findings on this issue. In the present paper, the experimental results are organized in a theoretical light in order to address a strategic micro-gravity-based approach to spray combustion, which integrates theory, numerical simulation as well as micro-gravity experiment. The content of the present paper covers the systematic understanding of inter-droplet flame propagation characteristics revealed through micro-gravity experiments on linear droplet array and spray, proposal of a percolation theory which relates the microscopic inter-droplet flame propagation characteristics to macroscopic spray combustion property and pressure effects on atomization and spray combustion characteristics