Prediction of In-Bore and Aerodynamic Heating of KE Projectile Fins.

摘要

Current high velocity kinetic energy penetrator shell use fins made of aluminum to provide aerodynamic stability. Due to the high velocity of the shell and the requirement to keep the drag of the shell to a minimum, these aluminum fins are very thin, a maximum thickness of 4 mm is typical. The thin cross section of the fin and the low melting point of aluminum combine to create a critical design problem. If the fins do not have sufficient mass to absorb and conduct away the high heat loads imposed in-bore and in-flight, the fins will ablate and cause erratic flight due to distortion fo the fin or the lack of sufficient fin area to maintain stability. This report discusses the development of an improved predictive capability to model the unsteady heat conduction of fin configurations of interest to the Army. Two modeling capabilities are described: (1) the full three-dimensional geometry of the fin for a fixed geometry; and (2) a quasi-three dimensional, two-phase modeling of the fin in which melting of the fin is simulated with a moving boundary that recedes as the material reaches melt temperature. Sample computations are shown which illustrate the unsteady, thermal response of KE projectile fins to aerodynamic heating.