Research Of The Aircraft Lateral Noise Level Prediction Method

Aircraft noise certification is an important part of the aircraft airworthiness certification,in order to improve the efficiency of aircraft noise certification,it is a hope that the noise level can be obtained at the beginning of the aircraft design,so as to evaluate the airworthiness of the aircraft as soon as possible,and to shorten the cycle and cost of the new aircraft noise certification.Through the study on the flight procedure of aircraft noise measurement in aircraft airworthiness certification,calculation method of aircraft effective perceived noise level,aero acoustics,engine operating equation,establish the relationship between the maximum take-off weight,aircraft wingspan area,maximum engine thrust,engine by-pass,aircraft take-off climb rate and the aircraft lateral effective perceived noise level.Appling the relationship to calculation the noise level of the existing aircraft models and analyze the calculation error,the results show that the relationship can be used to calculate the effective perceived noise level of a double rotor aircraft with a range of 2 EPNdB.The validity of the relationship is verified,therefore,the relationship between the physical parameters of the aircraft and the lateral noise level can be used as a lateral noise prediction algorithm of new aircraft.Then the influence of various aircraft physical parameters on the lateral noise level is analyzed by using the noise prediction algorithm,the results indicate that the higher engine bypass ratio and reduce the maximum engine thrust,increasing the wing area can effectively reduce the plane lateral EPNL,to provide reference for improving the airworthiness of aircraft noise in the future.According to the lateral noise prediction algorithm,using Visual Basic programming language to develop the aircraft boundary noise prediction system,the system can be used to verify the validity of the noise prediction algorithm,and to predict the noise of the new aircraft models.According to the physical parameters of the C919 aircraft,using the aircraft boundary noise prediction system to calculate C919 aircraft lateral EPNL,comparing the predicted value of the aircraft noise with the maximum allowable noise,the results show that the C919 aircraft complies with approved lateral noise airworthiness requirements.