Experimental study of ablative materials by oxyacetylene flame flow system

The motor components and body of missiles are protected by insulators, which are thermal insulation materials that limit the high-temperature effect from propellant burning to ensure the safety of the shell. Up to the present time, nitrile butadiene rubber, ethylene propylene diene monomer (EPDM), silicon rubber, and polyisoprene have been employed in the insulator matrix and applied to solid-propellant motors. For the testing equipment, the oxyacetylene ablation performance test system is simple, economic, and useful to estimate the thermal processes of ablative materials. Thus, in this study, this system is used to investigate the relative thermal insulation effectiveness of V-44 (used as control), EPDM/Kevlar, and I-58. The results show that when the heat flux is smaller than 280 W=cm², the erosion resistance rate of V-44 is better than those of EPDM/Kevlar and I-58; however, when the heat flux is over 350 W=cm², the difference in their erosion resistance rates is less obvious. Furthermore, the ablation performance of I-58 is worse than those of V-44 and EPDM/Kevlar. However, I-58 is better for the application of short-distance missiles, since it provides better bonding between the propellant and motor case. By contrast, EPDM/Kevlar exhibits better results for the applications as insulators in aerospace and military installations.