Chemically Reactive Flows in Airbag Inflator Chambers

Airbags are part of an important vehicle safety system, and the inflator is an essential part that generates a specific volume of gas to the airbag for a short duration of time. Recently, we have developed numerical models of automotive airbag inflators in conjunction with the LS-DYNA® chemistry solver. In this study, detailed and comprehensive descriptions for theoretical models are developed for a conventional pyrotechnic inflator (PI) and a compressed, heated gas inflator (HGI). For the model validation, the closed bomb test was executed and compared with an experimental data, In case of pyrotechnic inflator, zero dimensional model in conjunction with a solid propellant grains (e.g. NaN3/Fe2O3) is applied and the results are compared with existing data. In HGI model, a 2-dimensional with multi-species chemically reacting flow was calculated in the combustion chamber. Detailed and comprehensive descriptions for constructing the keyword flies will be given and the results for the two models will be discussed. The present study should find wide applications in designing advanced inflator models and predicting airbag performance by coupling to LS-DYNA® airbag solvers (i. e., ALE/ CESE).