HIGH TEMPERATURE OXYGEN INDEX APPARATUS

TO PROVIDE A REALISTIC FIRE RESISTANCE RANKING OF HIGH TEMPERATURE MATERIALS, LIMITING OXYGEN INDEX (LOI), MEASUREMENTS SHOULD BE MADE AT ELEVATED TEMPERATURE. THE MORE FIRE RESISTENT THE MATERIAL, THE HIGHER THE TEMPERATURE REQUIRED. CURRENT COMMERCIAL INSTRUMENTS HAVE THE CAPABILITY OF OPERATING UP TO 400 DEG C. HOWEVER, IMPROVED MATERIALS, ESPECIALLY COMPOSITES, REQUIRE EVEN HIGHER TEMPERATURE MEASUREMENTS. ADVANCED FUEL RESEARCH, INC. (AFR) HAS AN EXISTING TRANSPARENT WALL REACTOR (TWR), MEASUREMENT INSTRUMENTS, AND KNOW HOW NEEDED TO DESIGN AN LOI TEST APPARATUS CAPABLE OF OPERATING AT TEMPERATURES FROM 400 TO 800 DEC G. THE EXISTING FACILITY PROVIDES A COLUMN OF PREHEATED GAS WITH UNIFORM TEMPERATURES OVER A VOLUME 80 MM IN DIAMETER BY 200 MM HIGH. THIS VOLUME IS SUFFICIENT FOR A TYPICAL TET SPECIMEN. TO DESIGN AN LOI TEST APPARATUS, IT IS IMPORTANT TO UNDERSTAND THE SPECIMEN HEATING AND COMBUSTION BEHAVIOR. TO PERFORM THIS FUNCTION, AFR'S TWR HAS A COUPLED FOURIER TRANSFORM INFRARED (FT-IR) SPECTROMETER CAPABLE OF MAKING MEASUREMENTS OF GAS CONCENTRATIONS AND TEMPERATURE AND SPECIMEN SURFACE TEMPERATURES. AN IMPORTANT FEATURE OF THE FINAL TEST APPARATUS WILL BE THE MAINTENANCE OF A UNIFORM TEMPERATURE AT THE FLAME FRONT. SEVERAL POSSIBILITIES INCLUDING AN EXTENSION OF STANTON REDCROFT'S GRADED COLUMN HEATER AND THE USE OF A BUFFER GAS LAYER (AS IN THE TWR) WILL BE TESTED. WE WILL ALSO EXPLORE THE POSIBILITY OF SENSING THE FLAME FRONT AND USING A FEEDBACK LOOP AND TRANSLATION APPARATUS TO KEEP THE FLAME FRONT AT A CONSTANT ELEVATION. DURING PHASE I, WE WILL MODIFY THE TWR TO ALLOW TESTING OF STATIONARY AND TRANSLATING SOLID SAMPLES, AND MAKE MEASUREMENTS AT TEMPERATURES OF 400, 5000, 600, 700, AND 800 DEG C ON VARIOUS KINDS OF TEST SAMPLES. FT-IR MEASUREMENTS WILL BE MADE OF THE TEMPERATURES OF GASES AND THE TEST SAMPLE SURFACE DURING THE EXPERIMENTS TO ASSESS MAXIMUM TEMPERATURES, TEMPERATURES UNIFORMITY, AND HEAT TRANSFER PROCESSES....THE RESULTS WILL BE EMPLOYED TO DEFINE THE BEST CONDITIONS AND MAKE A PRELIMINARY DESIGN FOR A PROTOTYPE SYSTEM.