Solid Rocket Motor Ignition Process Flow Numerical Study

Along with the enhancement of the performance of the modified double-base propellant, the service life of the weapon could be expanded by replacing the composite propellant with the modified double-base propellant in the solid rocket motor, where the former is adhered to the combustion chamber by casting but the latter could be set in the combustion chamber freely. But when improving the solid rocket motor in this way, ignition failure often appeared. In order to solve the problem, this paper investigated the internal flow in the solid rocket motor with the CFD software.In this paper, a simplified two-dimensional flow ignition transient process model basis on turbulence unsteady-compressible N-S equations in solid rocket motor was established. At first, the paper simulated the spreading process of the ignition gas in combustion chamber, under the conditions of different igniter pressure, without regard to the combustion of propellant .With the simulations, the distributions of pressure and velocity and the change events of them were got, also the influence of ignition pressure on the ignition process is analyzed. Then, the paper simulated the ignition transient process considering the combustion of propellant. The simulation results indicated the distributions of different physical quantities and described the rising process of the pressure in the combustion chamber, and the influence of propellant shape on the ignition transient process was analyzed.Without regard to the combustion of propellant, when igniting the modified motor, it is shown that the special shape of the propellant leaded to the nonsynchronous spreading of the combustion gas between the inner pipe and the ring-like channel, which produced the pressure difference between them. When increasing the igniting pressure, the pressure differences rose up and ranged with time. The ignition delay time shorten when increasing the ignition pressure, while the pressure in the combustion chamber rose up in the ignition process. Considering the propellant combustion in the ignition procedure, the propellant ignition in charge gap was posterior to the pipe in combustion chamber rear part .In around the propellant charge gap's propellant ignition, pressure difference has a great change. The gaps both at the head and the rear of the combustion chamber had a great affect on the combustion gas spreading, and the whirlpool appeared there. The research results will private reference works for the solid rocket motor improved design and the ignition fault diagnosis.