Ricerc@Sapienza

Hybrid propellant rockets have been proposed as a valuable choice for future-generation space propulsion systems, and the Computational Fluid Dynamics (CFD) modeling of this class of devices has raised a considerable interest in the scientific community. The development of suitable simplified chemical kinetics mechanisms, representing a trade off between CFD accuracy and computational costs, is of great interest.

In this context, a set of simplified chemical kinetics mechanisms for hybrid rocket applications using gaseous oxygen (GOX) and hydroxyl-terminated polybutadiene (HTPB) will be obtained starting from a 561-species, 2538-reactions, detailed chemical kinetics mechanism for hydrocarbon combustion.

This set mechanisms will be used for predictions of the oxidation of butadiene, the primary HTPB pyrolysis product.

The simplification will be carried out systematically by means of a Computational Singular Pertur-bation (CSP) based algorithm. The simplification algorithm will be fed with the steady-solutions of classical flamelet equations, these being representative of the non-premixed nature of the combus-tion processes characterizing a hybrid rocket combustion chamber. The flamelet steady-state solu-tions will be obtained employing pure butadiene and gaseous oxygen as fuel and oxidizer bounda-ry conditions for a range of imposed values of strain rate and background pressure. Finally, a com-prehensive strategy will be employed to obtain simplified mechanisms capable of reproducing the main flame features in the whole pressure range considered.