Experimental and theoretical study of 2-ethylfuran spherical expanding flame: Cellularization, intrinsic instability and self-acceleration

The intrinsic instability and cellularity of 2-ethylfuran (2-EF) spherically expanding flame were investigated using experimental and theoretical analysis. The development and saturation time of initial and secondary cracks, crack length, cell number, and average cell area on the flame front surface were quantified using image processing techniques. The results showed that the initial cracks grow linearly, and are mainly influenced by the equivalence ratio. As the equivalence ratio increases, the number of initial cracks increases and spreads widely, which influences the variations in cell number and average cell area. In addition, the effect of initial and secondary cracks on flame instability or cellularity was analyzed. It was indicated that the influence of initial cracks on flame cellularity mainly increases with increasing equivalence ratio, but the appearance of secondary cracks increases with increased equivalence ratio and initial pressure. Finally, the self-acceleration of the 2-EF cellularized flame was also investigated, which suggested that the flame self-acceleration increases with increased equivalence ratio and initial pressure.