Numerical investigation on muzzle flow characteristics for small combustion chamber with embedded propelled body

Achieving a smaller size and lighter weight without affecting the launch performance is an important goal in the design of special launch equipment systems such as micro air vehicles and gun propulsion systems. An embedded structure is applied to small chamber systems to save launch space. This paper aims to illustrate the launch performance and muzzle flow characteristics of the embedded structure. The mathematical model of the launch process with a two-stage ignition is established. The muzzle flow model is used to simulate the launch process. The numerical method is verified by experiment. Numerical results indicate that a 21.1% space saving and a 4.2% muzzle velocity increase can be achieved by the embedded structure. The effect of the embedded structure on the muzzle flow is investigated. In the launch process, the Mach disk of the traditional structure travels farther, but that of the embedded structure catches up due to the greater velocity. The pressure oscillation of the embedded structure is larger, but the range of the oscillation is smaller. In the development process, compared with the traditional structure, the main parameters of the embedded structure, such as pressure and Mach number, are greater, which may lead to the launch risk. The findings will be applied to improve the design of small launchers.