DEVELOPMENT OF A HIGH-TEMPERATURE DIRECTIONAL SPECTRAL EMISSIVITY MEASUREMENT SYSTEM

WE PROPOSE TO DEVELOP A NEW HIGH-TEMPERATURE DIRECTIONAL SPECTRAL EMISSIVITY MEASUREMENT SYSTEM BASED ON A SPECIAL INTEGRATING SPHERE CONFIGURATION. CURRENTLY AVAILABLE SYSTEMS MEASURE ONLY THE NORMAL EMISSIVITY AT TEMPERATURES APPROACHING 1000 DEGREES CENTIGRADE WITH UNKNOWN ACCURACY, BY MEASURING THE EMITTED FLUX WHICH IS HIGHLY SENSITIVE TO TEMPERATURE UNCERTAINTIES. THE PROPOSED APPROACH MEASURES THE EMISSIVITY IN ANY DIRECTION (NORMAL TO 80 DEGREES) IN THE WAVELENGTH REGION 0.25 M - 25 M, FROM ROOM TEMPERATURE TO 3000 DEGREES CENTIGRADE WITH A THEORETICALLY ESTABLISHED ACCURACY (TO BE CONFIRMED EXPERIMENTALLY) BY MEASURING THE REFLECTED ENERGY WHICH IS INSENITIVE TO SAMPLE TEMPERATURE UNCERTAINTIES. THE INNOVATION ADDRESSES THE WIND TUNNEL INSTRUMENTATION AREA TO MEASURE TEMPERATURE AND HEAT FLUX IN THE RANGE 1500 DEGREES CENTIGRADE - 3000 DEGREES CENTIGRADE. WITH KNOWN DIRECTIONAL SPECTRAL EMISSIVITY, THE TEMPERATURE IS DIRECTLY OBTAINED FROM THE EMITTED FLUX. THE MAIN OBJECTIVE IS TO VALIDATE THE MEASUREMENT PROCEDURE AND THEORETICAL ACCURACY EXPERIMENTALLY AT TEMPERATURES REACHING 3000 DEGREES CENTIGRADE. THIS WILL BE DONE BY ASSEMBLING THE INTEGRATING SPHERE CONFIGURATION AND OTHER ESSENTIAL EQUIPMENT IN AN EXPERIMENTAL MEASUREMENT SYSTEM. IN PHASE I, THE CONCEPT FEASIBILITY WILL BE DEMONSTRATED AT ROOM TEMPERATURE; IN PHASE II, THE RESEARCH WILL BE DIRECTED TOWARD DEMONSTRATION AT HIGH TEMPERATURES. THE MAIN ANTICIPATED RESULT IS THE DEVELOPMENT OF A HIGH-TEMPERATURE HIGH-ACCURACY DIRECTIONAL EMISSIVITY MEASUREMENT SYSTEM.