The Interior Acoustic Fields Prediction Analysis On The High-speed Train Using An Energy Density Model And Design Of Software For Prediction

As the high-speed railway developing, the speed of the trains keeps on augmenting. Many problems previously neglected due to the relatively low speed have become critical and affect the further development of the high-speed railway. The noise generated when the train is running mainly consists of traction electric system noise, wheel/rail contact noise and aerodynamic noise. According to previous studies, the aerodynamic noise of the high-speed train is determined by the translational velocity u, its level is proportional to six to eight power of the velocity u. Therefore, the aerodynamic noise will improve significantly as the speed goes up. When the high-speed train runs at 250km/h, the aerodynamic noise will out-weigh the noise caused by the wheel and rail, thus becoming the principal noise source. The noise control of high-speed train was completed through the experiment. To increase the ability of noise control and the technical competitiveness of enterprises, it is significant to predict the interior noise at the beginning of high-speed train design. The prediction of noise is important for reducing design cycle and costs, improving design quality. This paper mainly discusses the numerical prediction of interior acoustic field in the high-speed train. The main research work is as follows:Firstly, this paper discusses the characteristics and applicable occasions of acoustic field numerical calculation method in the high-speed train. At medium and high frequency range, finite element method (FEM) or boundary element method (BEM) becomes less practical because of the time consuming on modeling. The classic energy method like statistical energy analysis (SEA) can only provide a global evaluation of response of the acoustic cavity.Secondly, a new method based on the acoustic energy density distribution equation is proposed and derived for predicting acoustic fields. The derived equation comprises descriptions of the direct field and reverberant field, taking account of diffusive reflection model. Besides, this paper also does prediction about the accuracy and validation.Then, this article will develop the software for predicting acoustic fields in high-speed train based on MES. For the convenience of engineering personnel, this paper develops a acoustic fields prediction tool based on energy density model, which provides a new calculation method and tool for interior acoustic fields prediction of high-speed train.At last, this paper predict interior acoustic field of high-speed train based on the simulation software developed before. This paper develops simplified energetic method (MES) to deal with the acoustics fields at middle-high frequency. In the future, we can combine FEM and MES to predict the noise of high-speed train.