Turbulent flame propagation with pressure oscillation in the end gas region of confined combustion chamber equipped with different perforated plates

Experiments were conducted in a newly designed constant volume combustion chamber with a perforated plate by varying the initial conditions. Hydrogen-air mixtures were used and the turbulent flame, shock wave, and the processes of flame-shock interactions were tracked via high-speed Schlieren photography. The effects of hole size and porosities on flame and shock wave propagation, intensity of the shock wave and pressure oscillation in closed combustion chamber were analyzed in detail. The effect of interactions between the turbulent flame and reflected shock or acoustic wave on the turbulent flame propagation was comprehensively studied during the present experiment. The results demonstrated that flame front propagation velocity and pressure oscillation strongly depend on the hole size and porosities of the perforated plate. The flame front propagation velocity in the end gas region increases as hole size increases and porosity decreases. The flame front propagation intensity in the end region of a confined space is strongly relevant to two competing effects: the initial turbulent formation and turbulent flame development. The experimental results indicated that an oscillating flame is associated with both the reflected shock wave and the acoustic wave. Meanwhile, different turbulent flame propagations and combustion modes were observed.