VELOCIMETRY WITH REFRACTIVE-INDEX-MATCHING FOR COMPLEX FLOW CONFIGURATIONS

THERE IS AN OVERALL NEED FOR VELOCITY MEASUREMENTS IN A WIDE RANGE OF APPLICATIONS THAT HAVE COMPLEX GEOMETRY, SUCH AS IN VSTOL AIRCRAFT DUCTS, HEAT EXCHANGERS, PUMPS, MANIFOLDS AND ROCKET ENGINES. A VELOCITY MEASUREMENT TECHNIQUE WHICH USES LASER-DOPPLER ANEMOMETRY AND REFRACTIVE-INDEX-MATCHING OF THE FLUID AND MODEL MATERIALS WOULD BE DEVELOPED FOR COMPLEX FLOW CONFIGURATIONS SUCH AS MODELS OF THE SPACE SHUTTLE MAIN ENGINE. EMPHASIS IS PLACEDON THE SSME APPLICATION BECAUSE IT HAS THE COMPLEXITY REQUIRED TO PROVE THE SUITABILITY OF THIS APPROACH IN A WIDERANGE OF COMPLEX CONFIGURATIONS AND BECAUSE THE DETAILED MEASUREMENTS WOULD HAVE INTRINSIC VALUE IN THE IMPROVEMENT AND DESIGN OF SSME COMPONENTS. PLEXIGLASS MODELS WOULD BE USED WITH FLUIDS THAT ARE ARRANGED TO HAVE AN INDEX OF REFRACTION SIMILAR TO THAT OF PLEXIGLASS AND THE FLOW CHARACTERISTICS WOULD BE DETERMINED WITH A FORM OF LASER-DOPPLER VELOCIMETRY. REFRACTIVE-INDEX-MATCHING TECHNIQUES CAN BE USED TO MEASURE AT INTERNAL LOCATIONS WHERE LASER BEAMS PASS THROUGH SEVERAL INTERFACES AND AT LOCATIONS IN CLOSE PROXIMITY TO WALLS. THE PROPOSED EFFORT WOULD EXTEND PRESENT CAPABILITY TO MORE COMPLEX CONFIGURATIONS AND LARGER FLOW RATES.