Research On The Method Of Predicting Flight Noise Based On Engine Fan Static Noise

With the rapid development of the civil aviation industry,the noise generated by aircraft has caused widespread concern.The engine fan is one of the important noise sources for modern civil aviation passenger aircraft.Therefore,people have conducted a lot of research on engine fan noise.However,previous noise predictions for engines and their components are noise predictions under static conditions and are not linked to the flight conditions required by airworthiness regulations.Therefore,the prediction of aircraft engine fan component noise under the flying conditions is more practical.Based on the Heidmann static fan noise prediction algorithm,we combine the aircraft's standard take-off procedure?aerodynamic parameters and the distance between the noise source and the measurement point.According to the static fan noise,combined with the Doppler effect,the attenuation generated during the sound propagation process and other factors,the static noise is converted into 1/3 obtain frequency sound pressure during the takeoff process of the engine in the same working state.Then can get the predict the predicted noise of the engine fan at the noise measurement point.Take the example of a Boeing 737-800 aircraft which equipped with a CFM56 engine to verify the effectiveness of the algorithm.Through MATLAB software programming,establish the prediction program,the fan noise can be predicted,and then calculate the overall effective fan noise level.It is compared with the noise value of the whole aircraft to verify the feasibility of the algorithm,analyze the prediction results and the factors which may affect the prediction results.With the ideas provided in this paper,noise prediction can be performed on other parts of the aircraft under different flight conditions of the aircraft,and then there is a predicted value for the overall noise of the engine.For the new airworthiness certification work can improve work efficiency,also can provide a certain theoretical basis for the engine in the design phase to achieve noise reduction purposes.