Book Description

A development program for a commercial supersonic aircraft and engines was sponsored by the Federal Aviation Administration during a five-year period from 1966 through 1971. The unique propulsion system, an afterburning turbojet, required acoustic suppression techniques to reduce its noise levels to those federally regulated for subsonic aircraft. An acoustic suppression research program was conducted by the General Electric Company to develop technology applicable to prototype and commercial supersonic engines. Primary emphasis was on jet noise suppressor development through model and engine testing. Various systems were studied including ejector pumping, simple mechanical primary and secondary suppressors, fluid injectants, multi-element tube nozzles, acoustically treated ejectors, highly segmented annular plug nozzles, etc. A research study on fundamental jet noise generation and reduction mechanisms was conducted at the General Electric Corporate Research and Development Center. In addition, investigatory tests were conducted for identification of total system noise. Application of a choked inlet and an open A sub 8 exhaust cycle were studied for noise reduction. Source turbomachinery noise generation and suppression through treatment application were investigated. This report summarizes the acoustic and aerodynamic technology with emphasis toward development of guidelines for future applications.