Unsteady Ballistic Code for Performance Prediction of Solid Propellant Rocket Engines

Solid Propellant Rockets (SPRs) by their very nature embody in their chemical properties and geometry the whole history of grain combustion from ignition to burnout. Thus, the development of robust and reliable ballistic codes for accurate prediction of SPR performance is critical for their cost-effective utilization in space propulsion applications, especially in the case of launch vehicle boosters where it can greatly contribute to limit the number of extremely expensive experimental tests. In this perspective the present work illustrates a numerical code (compiled with Fortran 77) based on the unsteady quasi-onedimensional conservation laws for the flow in SPR thrust chambers. By means of an ENO scheme and a Roe solver the code is capable of simulating the whole history of solid propellant grain combustion from ignition to burnout, thereby eliminating the matching problems associated with the use of two different codes for the transient and steady-state combustion phases. After successful validation in a number of test cases, sample results are presented in order to illustrate the effectiveness and accuracy of the program for the prediction of the internal ballistic of real SPRs .