Erosive and strand burning of stick propellants. I - Measurements ofburning rates and thermal-wave structures

Abstract

Burning-rate characteristics and thermal-wave structures of NOSOL-363 stick propellant under erosiveand strand-burning conditions were studied using a real-time x-ray radiography system, a strand burner setup, and fine-wire thermocouples. For the erosive-burning rate measurements, locations of instantaneous burning surfaces along the center perforation of a cylindrical propellant grain were determined by comparison of x-ray images obtained during a test and calibration images. The burning rates under strong crossflow conditions, deduced from the instantaneous burning-surface locations, were found to be much higher (up to 2.5 times) than the strand-burning rate of NOSOL-363 stick propellant. This study demonstrated that real-time x-ray radiography is a powerful and reliable tool for nonintrusive measurements of instantaneous burning rates in an optically opaque test chamber. From the strand-burning rate data and thermal-wave structures, a set of important thermochemical properties of NOSOL-363 stick propellant was deduced.