分层结构微孔球扁药制备条件对其燃烧性能的影响

Effects of Preparation Conditions on Combustion Performance of Microcellular Oblate Spherical Propellants with Layered Structure

以双基球扁药为研究对象,采用超临界CO_2升温发泡工艺制备了具有内部分层结构的微孔球扁药。分析了分层结构的形成机理以及解吸附时间和发泡温度对皮层厚度的影响。扫描电镜(SEM)结果显示,随着解吸附时间增加,未发泡皮层厚度增大,随着发泡温度升高,未发泡皮层厚度减小。密闭爆发器实验表明,不同皮层厚度的样品燃烧性能不同。在解吸附时间t_d=2 min,发泡温度T_f=85℃,发泡时间t_f=20 s时皮层厚度约20μm,具有良好的燃烧渐增性。皮层过厚或过薄都不利于燃烧性能的改善。可以通过控制解吸附时间和发泡温度,制备出具有合理皮层厚度的微孔球扁药,实现燃烧渐增性。

In order to improve the combustion performance of the oblate spherical propellants,the microcellular oblate spherical propellants with layered structure were prepared by supercritical carbon dioxide though temperature-rising method under certain saturation condition and foaming time（ tf）. The effects of desorption time（td） and foaming temperature（Tf） on the thickness of unfoamed skin were investigated by analyzing the formation mechanism based on classical nucleation theory and proved by the scanning electron microscope（ SEM） images. Results show that different thickness corresponding to different combustion properties. The closed bomb tests indicate that td= 2 min,Tf= 85 ℃and tf= 20 s with 20 μm unfoamed skin shows excellent progressive combustion performance,which is undetected in the samples with thicker unfoamd skin or the samples completely foamed. Therefore,the microcellular oblate spherical propellants with appropriate unfoamed skin thickness and progressive combustion performance can be obtained through controlling the desorption time and foaming temperature.