The Research Of Flight Noise Prediction Of Derivative Aircraft Based On Static Data

Aircraft noise control technology is one of the main objectives of the current green aviation concept,it is also a key technology for competition among the great powers in the aviation field.The level of aircraft noise is not only influent the experience,communication,even relate to the normal operation of the airborne equipment and the acoustic fatigue damage of the airframe structure.Aeroengine is not only the power source of the aircraft but also the huge noise source of aircraft.By predicting and analyzing the overall noise of the engine,the eligibility of aircraft noise under airworthiness conditions can be more accurately evaluated.This paper proposes a calculation method for predicting flight noise from the engine’s overall static data.This paper proposes a calculation method for the static data of the whole engine to predict the flight noise,so as to carry out the dynamic performance of the aircraft noise under airworthiness certification conditions assessment.This paper proposes a calculation based on static data of the engine to predict the dynamic performance evaluation of flight noise under airworthiness certification and derivative aircraft noise prediction.The main components of aero-engines,such as fan,compressor,combustion,turbine,and jet,are important aerodynamic noise sources.In this paper,the noise generation mechanism of each component and the principle of the semi-empirical algorithm used to predict noise are described firstly.Then,according to the engine noise prediction model ANOPP developed by NASA,use the semi-empirical noise prediction algorithms such as Heidmann,GECOR,and STONE to estimate the static noise of each component through the MATLAB programming and development prediction program.According to CCAR-36 noise airworthiness certification regulations and relevant airworthiness documents,drawn the aircraft take-off profile track under airworthiness certification conditions,mapped the static noise to the flight phth on the track,and calculated the noise propagation path.Then developed a flight noise correction algorithm.Based on the noise propagation path,the Doppler effect,the influence of engine number,the geometric divergence effect of sound propagation in the atmosphere,and the absorption attenuation effect are used to correct the static noise.Besides,considering the interaction between aircraft structure and engine installation position in actual flight,based on the insertion loss of noise barrier,calculated the noise attenuation loss by the influence of wing shielding,and analyzed the acoustic radiation characteristics,attenuation rules,and spectrum characteristics of wing shielding in different flight stages during takeoff.By combining the revision algorithm with the wing shielding,we can get the following conclusions: 1.Most of the noise measured at the noise receiving point is low-frequency noise,and the value changes with the increase or decrease of the noise propagation distance;2.Different from static noise performance,the noise source that has the greatest impact on the ground during the take-off path is changed from fan noise to jet noise,which is related to their noise frequency characteristics;3.As the noise propagation path moves from the leading edge of the wing to the trailing edge of the wing,the influence of the wing shielding effect first increases and then decreases,and the higher the engine noise frequency,the more obvious the shielding attenuation.Finally,by compiling the calculation method of airworthiness certification noise standard,calculated the airworthiness noise limit value and converted the predicted flight noise to the airworthiness certification standard value.The 10 d B drop range of the predicted PNLT is determined by the algorithm of first determining the calculation domain and then determining the calculation point,then recalculated the instantaneous sound pressure level.Compared the predicted noise data with the airworthiness noise data of ARJ21-700,the results showed that the algorithm of predicting flight noise based on static data can meet the requirements of airworthiness certification,and can also be applied to the subsequent derivative aircraft airworthiness noise prediction.