study the concepts for silent propulsion system

Abstract

noise emitted by commercial aircraft has been one of the most critical environmental issue , such as large number of people effected by aviation noise .The International body ICAO sets the common rules for the level of noise & engine emission through Annex 16 to the Chicago Convention 1944. Since the Most of aircraft noise is emitted by propulsion system, the major objective of this project is to review, study and optimisation of the recently techniques of design , that can achieve the concept of silent propulsion system (30 dB noise reduction). Ultra high bypass ratio engines with the influence of fan pressure ratio on engine noise emission , in addition to the concept of distributed propulsion system with high aspect ratio nozzle are two basic branches of this project. A300-600 powered by trent 500 was taken as case study for optimization the effet of fan pressure ratio on jet velocity as well as on jet noise emissions under normal takeoff flight conditions .Another case study was carried out for optimization the Influence of high aspect ratio nozzle on jet noise emissions . The fan pressure ratio was adjusted , and the optimum jet area was estimiated for ( 30 EPNL dB) reduction which can achieve the concept for silent propulsion system.