Comparison of Computational Analysis with Flight Tests of a 40mm Solid-Fuel Ramjet Projectile

摘要

Flight tests of fueled and inert projectiles and a computational analysis of the non-burning internal flowfield have been used to study the performance of 40mm Solid-Fuel Ramjet (SRFJ) projectiles. These projectiles, as originally designed, did not produce detectable thrust in flight. the 40 mm SRFJ is essentially scaled down from a successful 75mm round. Design modifications to the 40 mm SRFJ aimed at reducing the internal velocity and/or increasing internal turbulence yielded slight performance improvements. Alternate solid fuels were found to improve thrust generation. Computational modeling is used to investigate the differences in the non-burning internal flow for 75mm and 40mm SRFJ projectiles. Analysis of internal wall pressures, shock waves and flow separation reveals that the internal flow for the 40 mm geometry can be notably different from that of the 75mm geometry. These differences may have an effect on fuel ignition and burning. However, the computational analysis does not address the effects of projectile axial spin. (FR)