Research On The Noise Of Muzzle Jet And Muzzle Silencer Of The Pistol

The strong noise generated by firearms will cause a series of physical and psychological harm to the shooter and nearby personnel.The installation of a silencer on the muzzle of the firearm can greatly reduce the noise of the muzzle flow when the weapon is fired,thereby achieving "Silencing" effect.This article first introduces the development status of domestic and foreign silencers and the development status of numerical calculation methods applied to muzzle noise.Early research on silencers is mostly based on theoretical calculations of relatively simple structures,including the internal structure and noise field of muzzle numerical research is still relatively weak.In order to study the muzzle noise,this paper introduces the formation process and physical characteristics of the initial flow field in the muzzle flow field.According to the typical structure diagram of the under-expanded jet of gunpowder gas,the wave system formation process,spatial characteristics and muzzle of the gunpowder gas flow field are analyzed.The composition of noise sources provides a theoretical basis for the analysis of muzzle noise.For muzzle shock wave and jet noise,in addition to distinguishing the two from the peak of overpressure,the difference between the two is explained in terms of physical characteristics,damage mechanism,and research scope,which provides the base for the numerical calculations and data treatment.In order to study the influence of the internal structure of the muffler on the muzzle noise,and to develop a more efficient and resistant muffler,this article first adopts the CFD-CAA "two-step method",combined with the dynamic mesh technology,to solve the muzzle flow filed of a 9mm pistol containing the bullet numerically.That is,the muzzle flow field is calculated by the LES method first,and then the transient sound field is obtained by solving the FW-H acoustic wave equation.In order to verify the feasibility of the numerical model,the muzzle flow field and the muzzle noise field were tested and analyzed,and the test results were compared with numerical calculations.The numerical calculation flow field characteristics are in good agreement with the experiment,and the noise values of each measurement point were consistent with each other.The error between the test results is less than 5%.On the basis of the validity and feasibility of the above-built model,the numerical calculation model of the silencer is verified by mesh independence to ensure the calculation accuracy.The dynamic mesh technology to treat the bullet movementand the same numerical calculation method were used to study the number of different silencer bowls and different silencer bowl inclination angles.For the silencer with the inclination of the sound bowl,the influence of the different structures of the silencer bowl on the internal flow field of the silencer and the muzzle noise field of the silencer is analyzed in detail.The conclusions obtained can provide a certain direction and reference for the development of the silencer.