Research On Mechanism Of The Fluid And Structure Interaction Between Shock Wave And Solid Propellant Grain Crack

Cracks in propellant grains of SRM can originate during manufacturing, long haul, long term storage , service treatments and the preparation time for launching. These cracks may interact with the shock which is produced by the process of the pressure effect of ignition, make the internal ballistic parameters deviate from the design data, and influence the work of the SRM.In this paper, considering the elasticity of the propellant grains, the fluid and structure interaction problem has been simulated by the loose coupling method. The pressure of the flow field is computed by solving the 2-D time-dependent Euler equations cast in an Arbitrary Lagrangian-Eulerian(ALE) framework, using the cell-centered finite-volume scheme. The distance of the structure surface is computed by solving the structure dynamic equations, using the subsection precise time-integration method which is described in the finite element method. In every step, the pressure field of the fluid is computed first and the data is passed to the structure program afterward, then the distance of the structure surface is computed and the data is fed backed to the fluid program afterward. As the boundary of the flow field is moving, it is necessary to use the dynamic unstructured mesh technology.The boundary distortion of the grain crack and the changing of the flow filed are given in this paper. By comparing the flow field and pressure-time line of the rigid crack with those of the elastic crack, we discover that the big elastic parameter solid is sensitive to the pressure changing. If the elasticity is considered, the value and the surge frequency of the pressure will change erratically, but the poison parameter has few effects on them.