VELOCITY OF SOUND MEASUREMENTS FOR THE DETERMINATION OF GAS TEMPERATURE

INSTRUMENTATION IS NEEDED IN RESEARCH AND DEVELOPMENT FOR TESTING THE AEROTHERMOCHEMICAL PROPERTIES OF GASES AT HIGH TEMPERATURES, UP TO 5000 C. APPLICATIONS OCCUR NOT ONLY IN THE DEVELOPMENT OF VEHICLES FOR HYPERSONIC FLIGHT, BUT ALSO TO PROVIDE MEASUREMENTS IN FUNDAMENTAL RESEARCH IN PLACES AND UNDER CONDITIONS NOT PRESENTLY POSSIBLE. TEMPERATURE IS DEFINED FOR THOSE GASES NOT IN THERMODYNAMIC EQUILIBRIUM AS THE TRANSLATIONAL TEMPERATURE, I.E., THAT TEMPERATURE WITH THE LEAST RELAXATION TIME AND THUS MOST EQUAL TO THE THERMODYNAMIC EQUILIBRIUM TEMPERATURE. THE TRANSLATIONAL TEMPERATURE OF GASES BOTH IN EQUILIBRIUM AND NON-EQUILIBRIUM STATES, HAS BEEN MEASURED BY DR. AGOSTA. THE PRIMARY OBJECTIVE IN PHASE I IS TO DESIGN AN INSTRUMENT TO MEASURE THE VELOCITY OF SOUND IN GASES AND THUS DETERMINE TEMPERATURE UP TO 2000 C. AN EXPERIMENTAL FACILITY WILL BE MODIFIED TO PROVIDE PARAMETERS FOR THE DESIGN OF THE INSTRUMENT. INDEED, DURING THE PARAMETRIC STUDIES, VELOCITY OF SOUND MEASUREMENTS WILL BE MADE AND GAS TEMPERATURES DETERMINED THEREFROM PROVING AGAIN THE FEASIBILITY OF THE METHOD. THE DESIGN OF THE INSTRUMENT WILL BE SUCH THAT IT CAN BE EXTENDED TO DETERMINE TEMPERATURES UP TO 5000 C, MATERIALS WITHSTANDING.