Analysis Of Noise Characteristics In Electric Propeller Aircraft Cabin

With the vigorous development of electric aircraft,its comfort will become the most important assessment indicator,and the cabin noise has a decisive impact on aircraft comfort.Excessive noise also leads to the damage to the instrumentation in the cabin.The vibration not only caused damage to the strength of the fuselage but also threaten the safety of passengers.Therefore,it is a great significance that how to optimize the noise in the aircraft cabin.In the present paper,the noise of electric aircraft cabin is taken as objective.The researches of the numerical simulation of propeller aerodynamic noise,far-field noise test,aerodynamic noise optimization design,calculation and analysis of cabin noise response based on acoustic-vibration coupled mode and cabin noise test were carried out in this paper by adopting the theoretical analysis,numerical calculation and experimental research.In terms of aerodynamic noise,the FW-H model,the unsteady slip mesh and the large eddy simulation method are investigated to obtain the aerodynamic noise spectrum.The far-field noise experiment of the propeller under five speeds is completed,and the aircraft aerodynamic noise frequency domain characteristics and sound pressure intensity distribution are obtained.The validity of the numerical calculation model is verified by comparing the experimental data of the measuring point sound pressure level of the propeller with the numerical results.Based on the established calculation model and ensured the aerodynamic characteristics of the propeller,under 3 different rotation speeds,the distribution law of the sound pressure level of the propeller with different shape along the spanwise is analyzed,and the influence of the blade shape on the aerodynamic noise of the propeller is obtained.In terms of cabin noise,a model of the fuselage was built using the Catia,calculated and analyzed the structural and acoustic finite element modal,completed the acoustic-vibration coupling surface setting through Virtual.lab.After loaded the aerodynamic noise source,the calculation and analysis of cabin noise is completed by using the acoustic response calculation method based on acoustic-vibration coupled mode in FEM.The results show that the noise is regularly changed from high to low and from outside to inside along the fuselage.The most noisy location is behind the propeller and close to the fuselage in the cabin.The cabin noise test under five speeds is completed,and the aircraft aerodynamic noise time domain,frequency domain characteristics and the total sound pressure intensity distribution of six measuring points in the cabin are obtained.The research indicates that the cabin noise is mainly concentrated in the low frequency band with the frequency less than 1000 Hz,and the main influencing factor is the aerodynamic noise.The total sound pressure level of different measuring points is roughly the same,the total sound pressure level of human ear measuring point is the smallest,and the measuring point above the instrument panel is the highest,which is consistent with the conclusion drawn by the numerical simulation.