A Parametric Study of Gas Flow and Flame Spreading in Packed Beds of Ball Propellant. Part I. The 108.4mm Chamber with 7.62mm I.D.,

摘要

A parametric study of gas flow and flame spreading in porous beds of ball propellant was carried out in three vented chambers, 58.5 mm, 108.4 mm, and 201.6 mm, with 7.62 mm I.D. In part I of this study, the bed length was maintained at 108.4 mm while the principle variables were the primer vent geometry and the shot start pressure is simulated by a shear disc. The results indicate that (1) the initial primer pulse and the primer vent geometry set the stage for all subsequent events, (2) intergranular pressure transmission contributes to the rupture of the shear disc, (3) propellant grain deformation and frictional forces at the chamber walls greatly effect the progress of the combustion wave through the bed. The major conclusions are that predictive modeling efforts cannot (1) assume homogeneous ignition across the face of the bed, (2) ignore the void space created by the initial primer blast and (3) ignore bed compaction by the initial primer blast and subsequent progress of the combustion wave through the bed. Other factors which must be considered are intergranular stresses, propellant deformation, and frictional forces at the chamber walls. (Author)