A Diffusive Gas Jet Model in PAM-SAFE for Airbag Inflation 930238
Among the forces acting on an occupant during the deployment of an airbag, the impact force due to gas jets coming out of the inflator may be important. Consequently, the semi-analytical theory of high-velocity gas jets including velocity spreading due to turbulent diffusion has been incorporated into the explicit finite element computer program PAM-SAFE for occupant safety. The jet model, described in this paper, takes into account the geometry and thermodynamics of the inflator, the transfer of jet momentum to the moving airbag and the distribution of momentum due to diffusion. Since the intersection of every jet with the airbag is computed each timestep, the algorithm is consistent with numerical airbag unfolding.
Experimental validation of the jet model has been performed at Automotive Systems Laboratory Inc. by firing actual inflators on rigid flat plates at several distances. These results show that the total force exerted on the plate does not depend on the distance, which confirms the applicability of momentum conservation, and that the time and magnitude of the peak force is in good agreement with the numerical results.
Citation: Groenenboom, P., Lasry, D., Subbian, T., and Narwani, G., "A Diffusive Gas Jet Model in PAM-SAFE for Airbag Inflation," SAE Technical Paper 930238, 1993, https://doi.org/10.4271/930238. Download Citation
Author(s):
P. Groenenboom, D. Lasry, Th. Subbian, G. Narwani
Affiliated:
Automotive Systems Laboratory, USA
Pages: 11
Event:
International Congress & Exposition
ISSN:
0148-7191
e-ISSN:
2688-3627
Also in:
SAE 1993 Transactions: Journal of Passenger Cars-V102-6
Related Topics:
Airbag systems
Mathematical models
Gases
Turbulence
Vehicle occupants
Logistics
Thermodynamics
Fire
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