ADVANCED GAS TURBINE AUGMENTOR ACOUSTIC CHARACTERIZATION

ACOUSTIC RESONANCE CREATES A PROBLEM WITH BOTH THE OPERATION AND THE DURABILITY OF CURRENT HIGH PERFORMANCE GAS TURBINE AUGMENTORS. FUTURE GAS TURBINES ARE EXPECTED TO HAVE AN EVEN MORE SEVERE ENVIRONMENT FOR AUGMENTOR RESONANCE. THE CURRENT LEVEL OF UNDERSTANDING OF THIS PROBLEM GIVES NO ASSURANCE THAT SATISFACTORY PERFORMANCE CAN BE OBTAINED FROM THE MORE ADVANCED AUGMENTORS WITHOUT MAJOR DEVELOPMENT EFFORT. THE PROPOSED PROGRAM WOULD INITIATE A BASIC STUDY OF THE RESONANCE MECHANISMS WHICH WOULD BE OF USE IN THE DESIGN OF PRESENT AND FUTURE AUGMENTORS. IN PHASE I, AN EXPERIMENTAL APPROACH WOULD BE USED WITH PREMIXED GASES STABILIZED ON BLUFF BODY FLAME HOLDERS USING NOZZLES WITH GEOMETRIES OF BROAD SIMILARITY TO THOSE UNDER CURRENT CONSIDERATION TO AUGMENT THRUST AND REDUCE SIGNATURES. THE EMPHASIS ON THE INITIAL MEASUREMENTS WOULD BE ON STATIC PRESSURE CHARACTERISTICS TO IDENTIFY NATURE, FREQUENCY ND AMPLITUDE OF THE OSCILLATION. THE IDENTIFICATION OF THE PARAMETERS INFLUENCING THE TYPE OF OSCILLATION, LOCATION OF NODES, ETC., SHOULD LEND TO IMPROVE METHODS OF ATTENUATING THE DISTRUBANCES, AND THESE WOULD BE INVESTIGATED IN PHASE II.