Muzzle Multiphase Flow Field Analysis Of Underwater Launching

Underwater launching become a research hotspot with the development of super-cavitation projectile technology.The underwater launching process of traditional weapons contained three phases: water vapor,water and gunpowder gas,and there was a phase change relationship between water and water vapor.The three phases were coupled to each other at the muzzle,and the formed multiphase flow field had a great influence on the projectile's muzzle posture.Research on the underwater launch muzzle multiphase flow field was an important factor to improve the shooting accuracy of underwater weapons.Underwater launch was divided into sealed launch and fully submerged launch.In order to study the muzzle multiphase flow field on these two launch models,the dynamic analysis of two launch processes was carried out.The internal trajectory models of two underwater launch models was based on reasonable assumptions.The internal trajectory data was calculated.In succession,the existing simulation models were briefly analyzed.Combined with the 6DOF model and dynamic grid technology,the suitable boundary conditions and discretization methods were selected.The numerical model required to calculate the multiphase flow field of the underwater launch muzzle was established.Based on the established numerical model,the two-dimensional numerical calculation of the sealed underwater launch process was carried out.The pre-shock wave was studied to obtain the pressure,density and velocity regulation of the pre-projectile gas with change of time;The initial flow field was studied to get the effect of different initial states on the movement resistance of the projectile out of muzzle;Without consideration of the movement of the projectile,the gunpowder gas flow field was studied to obtain its formation and development process and the regulation of pressure and density with change of time;The muzzle flow field with projectile movement was studied to obtain its formation and development process and pressure distribution characteristics.Based on the established numerical model,the two-dimensional simulation of the fully submerged underwater launch process was carried out.The study of the muzzle flow field without a muzzle device verified the accuracy of the numerical model.And the formation and development process of the muzzle flow field and the regulation of longitudinal pressure distribution with change of time were obtained.The muzzle flow field with muzzle device was studied to get its formation and development process.The influence mechanism of the muzzle brake on the muzzle flow field was analyzed and compared.