含碳酸钙的负压强指数复合固体推进剂燃烧机理

本文采用激光阴影高速摄影、扫描电子显微镜、X光电子能谱,对含和不含CaCO_(3)的三种夹心件及SO4-5A PU复合推进剂的燃烧过程、燃面形貌、化学成分和覆盖分数分别进行了研究和测定。结果表明:CaCO_(3)在低压下(〈1.96MPa)提高AP的燃速,在高压下(〉1.96MPa)起降速作用;CaCO_(3)与AP反应生成CaCl_2,并促使AP熔化;燃面上CaCl_2含量随压强上升而增加;PU熔化流动对AP表面的覆盖在mesa区内随压强而升高,在非mesa区的低压区也存在。基于以上实验结果,对含CaCO_(3)的PU负压强指数推进剂的燃烧机理进行了讨论。

COMBUSTION MECHANISM OF A COMPOSITE SOLID PROPELLANT WITH A NEGATIVE PRESSURE EXPONENT

To study the combustion mechanism of a AP-PU composite solid propellant with a negative pressure exponent, three types of sandwiches with or without an additive, calcium carbonate were prepared. The laser-shadow high speed cinephotomicrography was used to study the burning process of sandwiches and to determine the burning rates. The sandwich surfaces quenched by rapid depressurization were examined in SEM. The compositions and covering of molten binder over the AP crystal surface on the burned surface of the propellant were determined by means of X-ray photoelectron spectroscopy. Following results were obtained. During combustion of the propellant, the additive CaCO3 enhances burning rate of AP at low pressure (<1.96 MPa) and depresses it at high pressure (< 1.96 MPa). CaCO3 reacts with AP to produce the final product CaCl2 and promotes melting of AP on the burning surface. The concentration of CaCl2 on quenched surface increases with increasing pressure. There are covering of molten binder over the AP crystal surface on the quenched surface not on'y at the mesa pressure regime, but also at no mesa pressure regime. The covered area fraction of AP crystal surface increases with increasing pressure. Based on the experimental results, the combustion mechanism of the negative pressure exponent propellant is discussed in this paper.