An airbag is composed of a housing assembly, door assembly, cushion assembly, and an inflator. The inflator is an essential part that generates gas for the airbag. When an airbag is activated, it effectively absorbs the crash energy of the passenger by inflating a cushion. In the present study, tank tests were performed with newly synthesized propellants with various compositions, and the results are compared with the numerical results. In the simulation of the inflator, a zonal model has been adopted which consisted of four zones of flow regions: combustion chamber, filter, gas plenum, and discharge tank. Each zone was described by the conservation equations with specified constitutive relations for gas. The pressure and temperature of each zone of the inflator were calculated and analyzed, and the results were compared with the tank test data. The similarity of the pressure curve and closed bomb calculation show that the modeled results are well correlated with the experimental data. (C) 2011 Elsevier Ltd. All rights reserved.