Experimental study of anomalous combustion in solid propellant grain with defects

Anomalous combustion of solid propellant grain with primary defects such as crack, gas cavity, debonding and weak-bond was investigated. This paper presents the experimental investigation results from some recent test motor firings. A real-time X-ray radiography system was used to obtain the process pictures of grain structural destruction during static firing. Several defect propagation modes of solid propellant and its structural destruction conditions were put forward under the different defects and operating conditions. The serious coupling phenomena between ignition and combustion in a crack, gas cavity, debonding flaw and structure deformation were described. The propagation tendency at the flaw leading-edge and the propagation critical conditions were studied in details. The results provide some experimental bases and analysis method of evaluating combustion safety of solid propellant grain with defects. Some conclusions in the paper have been applied to fault diagnosis of some full-scale motor firing test.