Effect of obstruction ratio rate of change gradients on the deflagration characteristics of H₂-Air premixed gases

To investigate the effect of the gradient of obstruction ratio change rate on the H₂-Air premixed gas combustion explosion in the semi-confined space, Fluent software is used to simulate the explosion flame, turbulent turning and pressure wave coupling process under the conditions of obstacles with different obstruction ratios change rate. The results indicate that as the obstruction ratio's rate of change increases, flame propagation speed decreases, while pressure peak and pressure change rate increase. The flame front becomes sharper, and a positive change in obstruction ratio more significantly affects flame shape and speed than a negative change. At obstruction ratio change rates of −0.3 and −0.2, the flame front area and peak area reach their maximum values. At a change rate of 0.3, the pressure peak is 232 kPa, and the maximum pressure change is 126 kPa/ms, indicating the explosion intensity reaches its peak.