EML BORE DIAGNOSTICS

ACHIEVING THE HYPERVELOCITY POTENTIAL OF ELECTROMAGNETIC RAILGUNS IS IMPAIRED BY ABLATION OF BORE MATERIALS AND A LACK OF WELL VALIDATED UNDERSTANDING OF PLASMA ARMATURE PERFORMANCE. DEVELOPMENT OF BORE MATERIALS AND MODELING OF PLASMA ARMATURES IS HAMPERED BY THE LACK OF DIAGNOSTICS WHICH CAN ACCURATELY MEASURE THE IN-BORE ENVIRONMENT. A KEY DIAGNOSTIC WHICH WOULD BE EXTREMELY USEFUL FOR BOTH MATERIAL DEVELOPMENT AND PLASMA UNDERSTANDING IS DIRECT MEASUREMENT OF THE VERY HIGH HEAT FLUX TO THE BORE SURFACE. THIS PHASE I PROGRAM WILL DEMONSTRATE A BORE HEAT FLUX GAGE THROUGH PROOF-OF-CONCEPT TESTS IN AN ACTUAL EML. OUR ANALYSIS INDICATES THAT ACCURATE BORE HEAT FLUX MEASUREMENTS CAN BE ACCOMPLISHED BY USING A SMALL SLUG CALORIMETER CONSTRUCTED OF ADVANCED HIGH TEMPERATURE MATERIALS (WE ARE CONSIDERING EITHER PYROLITIC GRAPHITE OR THIN FILM DIAMOND COATING). THE GAGE WILL BE PLACE IN ONE OF THE BARREL INSULATORS TO ELIMINATE OHMIC HEATING ISSUES. WE WILL COMPLETE DETAILED DESIGN OF THE GAGE USING A TRANSIENT HEAT TRANSFER COMPUTER PROGRAM DEVELOPED FOR THE BORE ENVIRONMENT. WE WILL FABRICATE A PROTOTYPE GAGE AND TEST IN A SUITABLE RAILGUN, PREFERRABLY THE EGLIN AFB PUG FACILITY.