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An excellent flame suppression effect can be achieved using a novel porous brake. To understand the flame-suppression mechanism of a porous brake, combustion using a muzzle brake is investigated. A set of internal ballistic equations is employed to provide accurate velocity and pressure for a projectile moving to the muzzle. The multispecies transport Navier–Stokes equations, which incorporate complex chemical reactions, are solved by coupling a real gas equation of state, the Soave–Redlich–Kwong model, and a detailed chemical reaction kinetic model. The development of muzzle flow with a chemical reaction is simulated, and the interaction between chemical reactions with the muzzle flow field is numerically calculated to explain the muzzle combustion mechanism with a porous brake. The underlying mechanism is analyzed in detail. The results demonstrate that, first, the gas is fully expanded in the brake, leading to a reduction in pressure and temperature at the muzzle, thereby reducing the initial flame. In addition, the shock wave weakens due to the expansion and separation process, leading to a reduction in the mixture of gas and air, ultimately resulting in a reduction in the intermediate and secondary flames. [ABSTRACT FROM AUTHOR]

To further understand a muzzle combustion mechanism in high-altitude firing, the influence of supersonic flow on a muzzle combustion phenomenon is investigated. The set of internal ballistic equations is employed, providing accurate velocity and pressure when the projectile moves to the muzzle. Multispecies transport Navier–Stokes equations with complex chemical reactions are solved by coupling a real gas equation of state, the Soave–Redlich–Kwong model, and a detailed chemical reaction kinetic model. The development of muzzle flow with chemical reaction is simulated. The interaction of chemical reactions with the muzzle flow field is obtained by numerical simulation in order to explain the muzzle combustion phenomenon of fire at supersonic flight. The mechanism of muzzle combustion influenced by supersonic incoming flow is analyzed in detail. It is demonstrated from the results that the shock wave and the expansion of the jet are restrained so that the combustion is compressed behind the projectile, at the same time generating a second region of combustion behind the muzzle under the influence of supersonic incoming flow. [ABSTRACT FROM AUTHOR]

The mathematical and physical models of the underwater submerged gun are established to study the flow field distribution characteristics of the gun muzzle at different water depths. The Schnerr–Sauer cavitation model and the realizable k–ω transport turbulence model based on the Reynolds-averaged Navier–Stokes method are employed. The muzzle flow field for the 12.7 mm gun that is submerged launched underwater is numerically simulated by combining user-defined functions and overlapping mesh technology. The flow characteristics of the density, velocity, and pressure fields at the gun muzzle at different water depths are analyzed in detail. The results show that the muzzle flow morphology depends mainly on the pressure at different water depths. The muzzle flow field distribution in deep water is more flat due to the high value of water pressure, which limits the expansion of the muzzle gas, and the range of the velocity field of the muzzle flow field at 100 m is one time smaller than that at 1 m. [ABSTRACT FROM AUTHOR]