Flame propagation processes in a simulated combustor for heated-gas airbag inflators

An experimental investigation was conducted to study the flame propagation processes of premixed hydrogen/air flames in a test rig simulating conditions in heated-gas inflators for the advancement of the hybrid airbag device. The major objective was to observe the coupling phenomena of the igniter discharge and flame propagation process under different test conditions. Using high-speed cinematography, the flame-front propagation speed was found to be governed by the trajectory of the ejected igniter disk. Initial concentration of hydrogen has a dominant effect on the pressure-time history in the combustor. It was found that, for marginally lean mixtures, the occurrence of the nonreproducible feature of the second pressure hump, during the chamber depressurization process, was caused by the strong coupling between the igniter disk trajectory and the wake-flow induced reactions of entrained gases.