Numerical Research On Aerodynamic And Noise Characteristics Of Bionic Pantograph Bow Head Of High-speed Train

In recent years,the running speed of the train has achieved a qualitative leap,but the problems of aerodynamics and noise are becoming more and more serious.When the train is running at high speed,the pantograph plays a key role in collecting current.Its pantograph head is one of the main components producing aerodynamic noise under high-speed operation.Therefore,considering the aerodynamic problems of the pantograph head when driving at high speed,focusing on the structural optimization of the pantograph head plays a key role in the safe operation and development of the train.The research object of this paper is the pantograph head structure of high-speed train.Through the numerical simulation analysis of pantograph head by using hydrodynamics software,the pantograph head structures with different cross-section shapes are designed based on the principle of bionics.The aerodynamic and noise characteristics of pantograph head before and after optimization are compared and analyzed by using the basis of hydrodynamics and acoustic theory,so as to achieve the purpose of reducing drag and noise.Firstly,this paper discusses the basic theoretical knowledge of hydrodynamics and acoustic theory,which provides a theoretical basis for the establishment of bow head physical model and the analysis of its velocity,pressure and aerodynamic noise generation mechanism in the air flow field.Secondly,according to the principle of bionics,through the breakage of the penguin in the water,the long semi-circular electric arch bow cross-sectional shape is proposed.Therefore,in addition to the original rectangular bow head,5 bionic structural bow heads are designed and established,which are 16 half arc bow heads,semi-circular bow heads,8 half arc bow heads,circular pointed bow heads and pointed pointed pointed bow heads.Through the simulation of FLUENT software,the aerodynamic lift and resistance of each bow head under different speed conditions are numerically analyzed,and the velocity field,pressure field nephogram And the variation law of air flow field vector diagram,and analyze the influence effect of different bow heads on the flow field.The results show that the aerodynamic characteristics of the semi-circular bow are best,can achieve a good reduction effect,and the resistance at three speeds is reduced by 76.03%,76.24%,76.39%,respectively.Finally,by selecting the semicircular bow head with the best drag reduction effect and the original rectangular bow head for three-dimensional modeling,the aerodynamic characteristics and aerodynamic noise characteristics at different speeds are numerically simulated and compared.The comparison shows that the semicircular bow head has a good drag reduction and noise reduction effect,which shows that it can effectively reduce the tail vortex falling off and reduce its aerodynamic resistance at high speed.The resistance is reduced by 79.33%,78.60% and 79.04% respectively at the three speeds.At the speed of350km/h,the far-field aerodynamic noise is reduced by 7.384 d B,7.264 d B and 8.123 d B respectively at the three monitoring surfaces.