Influence of Charge Structure on the Cook-off Temperature Distribution of Solid Rocket Motor

To investigate the influence of the charge structure on the cook-off characteristics of the solid rocket motor, we established 3 simplified cook-off models with 3 different charge structures, including the composite, the mono tube and the star tube, for the solid rocket motor with HTPE propellant.We conducted a cook-off test of small-size cook-off samples with HTPE propellant at the heating rate of 1℃/min and 2℃/min, and based on this experiment result, we adjusted the parameters of propellant material.By using the FLUENT software, we conducted the numerical simulation of the models' cook-off behaviors with 3 different charge structures at different heating rates (β).The results show that the charge structure has influence on the cook-off response time, the ignition point and the fast or slow cook-off division.The star tube charge leads to a critical heating rate effect, i.e. the jumping change of the ignition point, whereas the mono tube charge does not.Under the condition of this study, the critical heating rate of the composite charge motor with a star tube section is 0.2℃/min, and the critical heating rate of the star tube charge motor is 0.3 and 0.5℃/min, that is, when 0.3℃/min≤β≤0.5℃/min the ignition point jump changes.