IN-SITU OPTICAL PROPERTY MEASUREMENT TECHNIQUE

A TWO ELEMENT APPROACH TO MAKING IN-SITU IR OPTICAL PROPERTY MEASURMENTS ON AIRCRAFT ENGINE EXHAUST SYSTEM COMPONENTS IS PROPOSED. THE FIRST ELEMENT IS A PORTABLE, FIELD USABLE SYSTEM TO MEASURE BRDF BASED ON A NOVEL SPECTROMETER DESIGN WITH NO MOVING PARTS AND HIGH OPTICAL THROUGHPUT. THIS MEASURES THE COMPONENT SURFACES IN-SITU WHEN THE ENGINE IS OFF. THE SECOND ELEMENT IS AN IMAGING SPECTROMETER TO MEASURE THE SPECTRAL AND SPATIAL RADIANCE DISTRIBUTION EMERGING FROM THE ENGINE IN A TEST CELL ENVIRONMENT WHEN THE ENGINE IS OPERATING. THIS REMOTELY MONITORS CHANGES IN THE OPTICAL PROPERTIES AS THE ENGINE IS TURNED ON AND BROUGHT UP TO NORMAL OPERATING CONDITIONS. A PHASE I WORK PLAN IS DESCRIBED THAT WILL ACHIEVE THE TWO SPECIFIC TECHNICAL OBJECTIVES THAT DEMONSTRATE THE FEASIBILITY OF THE PROPOSED APPROACH. THE FIRST IS A CAREFUL OPTICAL ANALYSIS OF THE PORTABLE INSTRUMENT TO CONVINCINGLY PROVE ITS SUPERIOR SUITABILITY FOR MAKING PORTABLE OPTICAL PROPERTY MEASUREMENTS. AERODYNE HAS PERFORMED MANY SUCH ANALYSES ON NOVEL AND CHALLENGING INSTRUMENTS. THE SECOND TECHNICAL OBJECTIVE IS A PRELIMINARY DESIGN OF THE IMAGING SPECTROMETER AND A CALCULATION OF ITS REFLECTANCE AND EMITTANCE MEASUREMENT ACCURACY IN THE STRESSING ENVIRONMENT OF AN AIRCRAFT ENGINE TEST CELL.