双脉冲固体发动机燃烧室 EPDM 绝热层烧蚀性能实验研究

In order to study the complicated ablation performance of EPDM insulation in the combustion chamber of a double-pulse solid rocket motor，an engine experiment scheme with working time of 15s and two ignition of 7.5s+7.5s was proposed. The surface morphology of the ablation specimen，the surface and section morphology of the carbonized layer and the three-dimensional configuration of the carbonized layer were obtained by SEM scanning and micron CT testing.The ablation rate of the specimen was calculated by the measurement results of the thickness gauge.The results show that the ablation rate of the EPDM insulation is higher than that of the conventional engine under the same total working time. Compared with the specimens in the traditional engine after a single thermal shock，the thickness of carbonization layer decreases by 50% and the overall porosity increases by 13% because of the double pulse engine after a second thermal shock.The density of the dense layer on the ablation surface also decreases.The ablation performance of EPDM insulation varies greatly under the secondary thermal shock when the double-pulse engine is in operation，which should be paid more attention to in the design process of the insulation in the combustion chamber.