THE OPERATION OF GAS TURBINE AUGMENTERS CAN GENERATE INTENSE ACOUSTIC PRESSURES WHICH INFLUENCE THE PERFORMANCE OF THE AUGMENTER AND THE DURABILITY OF THE STRUCTURE.

THE OPERATION OF GAS TURBINE AUGMENTERS CAN GENERATE INTENSE ACOUSTIC PRESSURES WHICH INFLUENCE THE PERFORMANCE OF THE AUGMENTER AND THE DURABILITY OF THE STRUCTURE. THESE PHENOMENA HAVE BEEN OF CONCERN FOR SEVERAL YEARS, PARTICULARLY IN THE OPERATION OF RAMJET ENGINES, AND HAVE BEEN THE SUBJECT OF SEVERAL TEST PROGRAMS. HOWEVER, THERE IS NO AVAILABLE ANALYTICAL OR EMPIRICAL MODEL OF THE GENERATING MECHANISMS THAT CAN BE USED TO EVALUATE CONCEPTS FOR REDUCING OR ELIMINATING THE PROBLEMS. THE PROPOSED OVERALL PROGRAM HAS THE OBJECTIVES OF DEVELOPING SUCH MODELS FOR AUGMENTER RUMBLE AND SCREECH, AND USING THE MODELS TO EVALUATE POTENTIAL NOISE CONTROL CONCEPTS THAT WOULD IMPROVE AUGMENTER PERFORMANCE UNDER PHASE I. THE MODELS WILL CONSIDER AXIAL AND TANGENTIAL OSCILLATIONS IN THE COMBUSTOR. AT HIGH FREQUENCIES THESE OSCILLATIONS WILL BE ASSOCIATED WITH ACOUSTIC MODES BUT THIS IS NOT NECESSARILY TRUE FOR AXIAL OSCILLATIONS. ASSUMPTIONS INTRODUCED WILL BE VALIDATED BY MEANS OF UP-TO-DATE DATA FOR ENGINE AUGMENTERS; THE DATA WILL ALSO BE USED TO VERIFY THE FINAL MODELS.