Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
Evaluating the effect of grain geometry and the particle size of ammonium perchlorate on the combustion of Base Bleed propellants in static firing tests
Submission Author:
Maurício Ferrapontoff Lemos , RJ , Brazil
Co-Authors:
Maurício Ferrapontoff Lemos, LAURILIO SILVA JUNIOR, GIL ROBERTO VIEIRA. PINHEIRO, Norberto Mangiavacchi, Daniel Chalhub, Leib Neubarth, Rachel Manhães de Lucena, Priscila Simões Teixeira Amaral, ANA PAULA DA SILVA, rafael pinto, william Ferreira
Presenter: Maurício Ferrapontoff Lemos
doi://10.26678/ABCM.ENCIT2022.CIT22-0640
Abstract
A traditional way to develop extended range munition (ERM) is through the insertion of the combustion products generated by the burning propellant in the rear part of the projectile. This is the so-called base bleed system (BB). This work aims to evaluate the performance of BB propellants as a function of grain geometries and the mean particle sizes of the ammonium perchlorate (AP) when tested in static firing. The static tests are performed on a lab-scale bench, designed and built in-house, where a cylindrical combustion chamber, with the same dimensions as the 114.3 mm projectile, is fixed to a sliding table. Thrust and internal chamber pressure are measured. The mass flow is corrected to account for projectile rotation and base pressure along the trajectory, using correlations from the literature. Results indicate that when the propellant regression rate is too high, it generates high mass flow rates in the early stages of the propellant combustion and rashly consumes the propellant grain. This is the case for the BB propellant with a smaller mean particle size of AP. On the other hand, a very low regression rate (with a coarser mean particle size of AP) leads to a delayed plateau of the mass flow regimes. Those effects on a real firing performance of Base Bleed propellant are discussed. Regarding propellant grain geometry, it affected mainly the ignition delay. Smaller internal diameter is related to a faster ignition process. Finally, the evaluations performed in this work are very useful for further estimation of aerodynamic parameters and projectile flight simulation in real operational conditions.
Keywords
static firing test, base bleed, extended range munition, Propellant, Ammonium Perchlorate
