Comparison of 2-acetylfuran, 2-ethylfuran, and 2-methylfuran spherically expanding flame intrinsic instabilities

The intrinsic instability of three furan derivatives, namely, 2-acetylfuran (AF), 2-ethylfuran (EF), and 2-methylfuran (MF), is experimentally and theoretically investigated and compared. A deep-learning-based end-to-end system is used to segment the cells and measure the crack length on the cellular flame front of the spherically expanding flame to quantitively investigate the flame morphology. Moreover, the flame front radius profile is quantitively investigated to shed light on the correlation between disturbance amplitude and flame radius. With the use of the linear stability model, the theoretical critical flame radius and Peclet number are obtained and compared to their corresponding experimental results to characterize the outset of cellularization and evaluate the flame instability propensity. Our analysis shows that compared with AF and EF, MF is prone to cellularization at a smaller flame radius and has a faster cell proliferation rate and crack length growth rate before reaching the hydrodynamic saturation limit. Meanwhile, the average area of saturated cells tends to be similar for the three furan derivatives. Furthermore, AF premixed flame does not exhibit cellularization before the flame radius is less than 45 mm in low initial pressure.