| The ignition-transient process in the tail device of a small solid rocket motor is a very short,complex,changeable physical and chemistry process,which is seriously affected by the type and quality of ignition composition and the tail ignition geometry.In the background of tail spacing ignition project of a small solid rocket,Compared with the traditional head ignition or the nozzle wall ignition,the transient ignition of resulting in abnormal ignition due to the spaced arrangement of the ignition device.The investigation of the internal flow field in the tail device of 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,the ignition-transient process of the tail igniter of a small solid rocket motor is simulated numerically.The research says:1.In this paper,based on the theory of a small solid rocket motor classical interior ballistics,four-order-Runge-Kutta method was used to compute the differential equations.Based on the lumped parameter method,the laws of energy releasing in the ignitor had been obtained with different mass of ignition composition.Specified the proportional relationship between the output pressure of the igniter and the mass flow rate of the gas.Offered the initial boundary condition of the numerical simulation of gas flow in the small solid rocket motor tail.2.The finite-volume solution of the unsteady,compressible Navier-Stokes equations,together with the structured grid system of high quality and the two-equation k—εturbulence model was used to numerically simulate the 3D axisymmetric flow field of a small solid rocket motor.Established a mathematical and physical model of transient ignition process with the consideration of the radiation heat transfer.3.Using Fluent software platform,a numerical study was performed to investigate the energy distribution of the internal flow field corresponding to the different gradually contracted cylindrical duct,which has narrow duct of different length of 18mm,23mm and 28mm.Found the relations of the structure of narrow duct and the laws of energy releasing.At the same time,under the condition that the igniter produces gas and particles,a numerical method was used to simulate the transient two-phase flow field in a small solid rocket motor with the aft-end igniter during the ignition period.It is not only provides theoretical guidance for the transient ignition process design,but also provides experience and help for practical proects. |
