"Electrothermal Gun Interior Ballistics Model Assessment"

THE ELECTRO-THERMAL-COMBUSTION (ETC) GUN CONCEPT WAS DEVELOPED AS AN ADVANCED TECHNIQUE FOR HYPERVELOCITY GUN SYSTEMS WHICH AUGMENTS THE ELECTRICAL ENERGY INPUT OF THE ORIGINAL ET GUN BY USING A REACTIVE WORKING FLUID. THIS HOWEVER HAS COMPROMISED THE ABILITY TO CONTROL THE INTERIOR BALLISTIC PROCESSED PRINCIPAL ADVANTAGE OF THE ET GUN CONCEPT. IN THE ETC GUN, THE GAS GENERATION RATE IS ONE STEP REMOVED (BY THE PLASMA JET MIXING AND REACTION RATES) FROM THE ELECTRICAL ENERGY DEPOSITION RATE THUS MAKING THE METHOD LESS CONTROLLABLE THAN THE ET GUN. IF THE DYNAMICS OF PLASMA JET DENETRATION AND MIXING WERE WELL UNDERSTOOD, THEN IN PRINCIPAL, THE CORRECT JET DYNAMICS FOR OPTIMUM PROJECTILE ACCELERATION COULD BE CREATED BY TAILORING THE ELECTRICAL PULSE SHAPE, AMOUNG OTHER THINGS. HOWEVER, DETAILED KNOWLEDGE OF PLASMA JET BEHAVIOR AT GUN OPERATING CONDITIONS IS CURRENTLY LACKING. ALTHOUGH IT IS GENERALLY UNDERSTOOD THAT JET PENETRATION AND MIXING PLAY AN IMPORTANT ROLE IN DETERMINING BALLISTIC PERFORMANCE, IT IS NOT CLEAR HOW TO IMPROVE JET CHARACTERISTICS TO OPTIMIZE PERFORMANCE. ONGOING RESEARCH PROGRAMS ARE DIRECTED AT IMPROVING THIS PROMISING APPROACH. THE SBIR PROGRAM PROPOSED HEREIN IS DESIGNED TO COPLIMENT THESE PROGRAMS BY UTILIZING A RECENTLY DEVELOPED FLUID DYNAMIC MODEL CAPABILITY TO ANALYZE THE IMPORTANT TWOPHASE TURBULENT JET MIXING PROCESSES CRUCIAL TO THE SUCCESSFUL OPERATION OF THE ETC CONCEPT. IT IS PROPOSED TO CONTRIBUTE TO THE UNDERSTANDING OF ETC GUN INTERIOR BALLISTICS AND, IN PARTICULAR, OF THE JET DYNAMICS AND MIXING PROCESS, BY UTILIZING THE TURBULENT TWOPHASE REACTIVE FLUID DYNAMICS CAPABILITY WHICH RESIDES IN THE MAGIC/BISON FLUID SYSTEMS CODES. THE PROGRAM WILL SPECIFICALLY ADDRESS JET DYNAMICS INCLUDING DROPLET FORMATION AND EVOLUTION MECHANISMS WHICH, IT IS BELIEVED, CONTROL PLASMA JET EVOLUTION AND THE RESULTING GAS GENERATION RATE. THE COMPUTATIONAL ANALYSIS OF THESE MECHANISMS WILL HELP PROVIDE THE CLUE TO IMPROVED ETC GUN PERFORMANCE.