Research On Acoustic Simulation Of Turbofan Engines

Civil aircraft noise is mainly composed of turbofan engine noise,so it is very important to study the prediction and simulation of turbofan engine noise.Since the noise component types of fan components include all types of turbofan engine noise,the simulation method applicable to fan noise is also applicable to turbofan engine noise.Therefore,based on the Heidmann fan noise prediction model and the noise prediction data and flight track obtained from ANP database,this paper uses Adobe Audition software to synthesize the fan noise in the flight audio signal of fan parts,so as to achieve the purpose of prediction and simulationFirstly,the physical size of turbofan fan and other relevant parameters should be input into the Heidmann fan noise prediction model to obtain the predicted value of fan noise under ground test condition.According to ANP database to get the flight standards track,flying over the location of the noise measurement point,and then on the basis of the static prediction results considering the doppler effect,turbofan engine fan noise spread from sound source to ground noise measurement point in the process,factors such as the attenuation in the air,then the conversion of a turbofan engine static data for turbofan engine in the process of with the plane took off,and the ground test run under the same working condition of a third octave sound pressure level.In order to verify whether the synthesis method proposed in this paper is accurate and correct,it is necessary to take the noise of a specific type of aircraft engine as an example to synthesize and compare the measured data.The Boeing737-800 aircraft equipped with cfm56-7b,for example,was chosen because the aircraft and its engines are widely used and data are easily available.Forecast due to large amount of calculation,so choose to write noise prediction method to calculate the predicted data,at the same time to predict program input parameters environment parameters such as size,after calculation,namely the turbofan engine fan parts forecast noise value,and then on the basis of the forecast data,using Adobe Audition software synthesis of fan noise.Aircraft flying in the process of the receiver to receive audio signal is constantly changing,in order to solve this problem,select as manypoints to calculate the noise data,respectively for audio signal synthesis will again after the audio signal pieced together in a certain way,finally by playing the synthetic noise and measure the audio signal,verify the effectiveness of the synthetic method.The audio signal can restore the real noise to a large extent and provide feedback mechanism for related researchers.At the same time,the noise of other components of turbofan engine in flight can also be synthesized.