0d unsteady-1d quasi-steady internal ballistic coupling for ROBOOST simulation tool

The work presented here deals with the non-negligible problem of simulating the internal ballistic and thus the performance prediction of a Solid Rocket Motor (SRM). The internal ballistic consists in the thermodynamic and fluid dynamic description of the combustion inside the rocket and the behavior of the propellant grain’s regression vs time. Many numerical and simplified analytical models have been used since the beginning of solid rocket’s industrialization; depending on the motor’s length-to-diameter ratio, zero dimensional or mono dimensional models are exploited in the preliminary design phase of a SRM, and steady or non-steady models are also used to predict the performances of the working phase under examination. The coupled zero-dimensional non-steady (0D-NS) and mono dimensional quasi-steady (1D-QS) ballistic model is the main state of the art for designing in a time and cost-effective fashion. An analytical model for the 0D NS – 1D QS internal ballistic is here developed and numerically implemented in a SRM simulator developed at the Propulsion Laboratory of the University of Bologna (Department of Industrial Engineering), named ROBOOST (Rocket BOOst Simulation Tool). An investigation of several commercial motors performances is then performed for validation’s purpose.