Theoretical and Experimental Investigation of Flamespreading Processes in Combustible-Cased, Stick Propellant Charges

摘要

Attention has shifted over recent years in the United States to the use of stick propellant in high-performance artillery charges. The substitution of the natural flow channels offered by a bundle of stick propellant over the problem of pressure waves so often associated with high-pressure gun malfunctions. Further, performance advantages may be realizable because of the higher natural loading density of stick propellant as well as unique hydrodynamic features associated with its geometry. However, recent testing has revealed that the postulated flow of igniter gases and flamespreading from the basepad forward through the bundle of sticks in a simple, one-dimensional manner may be significantly complicated by the presence of a combustible case, the initial permeability, mechanical strength, and ignition and combustion characteristics of which may play major roles themselves in characterizing the aforementioned sequence of events. The US Army has just completed development of a new top-zone propelling charge designated M203E2 and type classified M203A1 to replace the M203 Charge for the 155-mm, M198 Towed Howitzer. A number of these charges were modified to permit direct viewing of the interior of the charge and fired in the Ballistic Research Laboratory 155-mm Howitzer Simulator. Companion calculations were performed using the TDNOVA two-dimensional, two-phase interior ballistic code.