Turbulent combustion evolution of premixed hydrogen due to inherent instability and development space

Laminar combustion of hydrogen in a premixed state has the potential to transition into turbulent combustion.The results demonstrate that the hydrogen premixed flame exhibits selfacceleration, progressing through the laminar combustion phase, followed by a transitional combustion phase, and ultimately transforming into a turbulent combustion phase.These flame characteristics, including flame propagation velocity, flame pulsation, perturbation length, and flame thickness, all exhibit consistent three-phase behaviors.The turning points, referred to as the critical radii Rcr1 and Rcr2., mark the transition between different combustion phases.As the flame radius increases, the instability within the flame becomes more pronounced.When the radius exceeds Rcr1, spatial constraints due to wall reflections begin to influence the flame's development, altering the combustion dynamics.This phenomenon occurs as pressure waves are reflected by the walls, leading to alterations in the flow field within the combustion region, which ultimately influences the combustion parameters of the flame.In comparison, Conversely, a 30% increase in vessel volume leads to relatively minor variations in flame parameters.In instances of reduced space, the parameter that exhibits the greatest change is the heat release rate (HRR), which increases by 6.8%.Conversely, in the context of an enlarged space, the parameter that changes most significantly is the velocity, which decreases by 5.7%.