3D Numerical Simulation of Ignition Transient in SRM

This paper presents a three dimensional numerical code for the analysis of Solid Rocket Motor (SRM) pre-ignition transient. For motors with a 3D star-shaped "finocyl" region and high energy igniter, like the first three stages of the new European launcher "Vega", experimental results and preliminary quasi-1D and axisymmetric simulations show that this operative phase can be characterized by strong unsteady phenomena with the possible presence of nocive pressure oscillations inside the combustion chamber. Therefore in order to accurately design such kink of SRM the prediction capabilities of these pressure fluctuations has to be improved. A three dimensional (both cylindrical and rectangular coordinates), inviscid, compressible and multicomponent solver (named EoS) has been developed. It is based on a finite-volume Godunov-like scheme and adopts a cartesian structured grid. The code is written in Fortran 95 with Object Oriented style to ensure flexibility and easy maintenance/improvement (adding sub-models, parallelization etc). Some validation tests are presented. Also a preliminary analysis of Pre-Ignition Transient of a SRM, with a comparison between the experimental head-end pressure time-history and the numerical one, is presented.