EFFECT OF BOOSTER ACCELERATION ON INSULATOR EROSION

DATA FROM RECOVERED ROCKET MOTORS HAS CONVINCINGLY SHOWN THAT MORE CHARRING/EROSION OCCURS ON FORWARD DOME INSULATION DURING FLIGHT THAN IN STATIC FIRING. THE PROBLEM OF FLIGHT AMPLIFICATION OF CHARRING/EROSION HAS GREATLY INCREASED TO COMPLEXITY OF THE DESIGN PROCESS FOR FUTURE ROCKET MOTORS, ESPECIALLY THOSE SUBJECTED TO HIGH ACCELERATION. LARGE SAFETY FACTORSMUST OFTEN BE APPLIED RESULTING IN THICK, HEAVY INSULATION WITH UNCERTAIN RELIABILITY. A MECHANISTIC MODEL COUPLED WITH NEW LABORATORY TEST METHODS ARE NEEDED TO PROVIDE A METHODOLOGY WHICH CAN BE RELIABLY USED TO SCREEN NEW METHODS. THIS PHASE I PROGRAM WILL DEMONSTRATE A RELATIVELY SIMPLE LABORATORY TEST TECHNIQUE WHICH PROMISES TO CLARIFY THE DOMINANT MECHANISMS GOVERNING THE FLIGHT AMPLIFICATION PROBLEM. THE TECHNIQUE EMPLOYS A SMALL WIND TUNNEL COMBINING RADIATIVE HEATING AND OSCILLATORY ACCELERATION OF THE TEST SAMPLE TO ALLOW INDEPENDENT VARIATION OF EACH CRITICAL PARAMETER. BY INDEPENDENTLY VARYING EACH PARAMETER WE CAN DETERMINE THE RELATIVE IMPORTANCE OF EACH ONE, AND WHICH ONES ARE DOMINANT. ULTIMATELY DATA FROM THESE SIMPLE TESTS, PULSE DATA FROM MORE COMPREHENSIVE TESTS, CAN BE COUPLED TO WELL VALIDATED COMPUTER MODELS, SUCH AS THE CHARRING MATERIALS ABLATOR (CMA) CODE, TO PRODUCE A RELIABLE PREDICTIVE TOOL.