Research Of Ignition In Spinning Solid Rocket Motor With Aft-end Ignitor

The ignition of the solid rocket motor (SRM) is a very complex physical and chemistry process, which is composed of three component phases: ignition delay, flame spreading and chamber filling. The investigation of the internal flow field in a SRM during the ignition transient period is of practical importance, because the deep analysis of the transient internal flow field during the ignition period is useful to reduce the failure out of the ignition and improve the design. In this paper, a numerical procedure is presented to simulate the transient internal flow field in the rotating solid rocket motor with the aft-end igniter during the ignition period. The main works are as follows:1. In the paper, the finite-volume solution of the unsteady, compressible Navier-Stokes equations, together with the structured grid system and the two-equation k-e turbulence model is used to numerically simulate the 2D axisymmetric flow field of a SRM. The aft-end igniter is simplified, and is numerically simulated. The results show that the simplified igniter model can simulate the operation of the real igniter well.2. Under the assumption that the igniter produces hot gas only, a numerical method is used to simulate the transient internal flow field in SRM with the aft-end igniter during the ignition period. The hot gas produced by the igniter transfers heat to the propellant by convection. The result shows that there is still a portion of propellant un-ignited in the front of SRM. Obviously the results are not satisfying, and then radiation is considered in the heat transfer between hot gas and propellant. The results are better, which show that all portions of propellant are ignited, and the ignition delay is shortened.3. Under the condition that the igniter produces gas and particles, a numerical method is used to simulate the transient two-phase flow field in SRM with the aft-end igniter during the ignition period. The Euler-Lagrange model is used to solve the two-phase flow in this paper. When particles are attached to the surface of propellant, particles transfer heat to the propellant by conduction. The results show that the ignition delay is shortened largely because of particles, and the flame is not continuous.4. The rotational velocity has an important impact on the distribution of pressure and temperature in SRM. A numerical method is used to simulate the transient internal flow field in SRM with different rotational velocity during the ignition period. It is supposed that the igniter produces hot gas only, and the hot gas transfers heat to the propellant by convection. The result shows that influenceof the rotational velocity on the ignition delay is not obvious, and when the rotational velocity is increased, the ignition delay is increased a little. Obviously during the ignition transient period, the influence of the rotational velocity on the gas is not obvious, but the rotational velocity has an important impact on the track and distribution of particles. So the hot particles produced by the igniter should be considered in the numerical simulation of the ignition of the rotating RSM with the aft-end igniter.