Experimental investigation on the self-acceleration of 10%H2/90%CO/air turbulent expanding premixed flame

The self-acceleration characteristics of a syngas/air mixture turbulent premixed flame were experimentally evaluated using a 10% H₂/90% CO/air mixture turbulent premixed flame by varying the turbulence intensity and equivalence ratio at atmospheric pressure and temperature. The propagation characteristics of the turbulent premixed flame including the variation in the flame propagation speed and turbulent burning velocity of the syngas/air mixture turbulent premixed flame were evaluated. In addition, the effect of the self-acceleration characteristics of the turbulent premixed flame was also evaluated. The results show that turbulence gradually changes the radius of the premixed flame from linear growth to nonlinear growth. With the increase of turbulence intensity, the formation of a cellular structure of the flame front accelerated, increasing the flame propagation speed and burning speed. In the transition stage, the acceleration exponent and fractal excess of the turbulent premixed flame decreased with increasing equivalence ratio and increased with increasing turbulence intensity at an equivalence ratio of 0.6. The acceleration exponent was always greater than 1.5.