亚大气压下AP/HTPB微尺度稳态燃烧的数值模拟

为研究亚大气压下高氯酸铵/端羟基聚丁二烯(AP/HTPB)的燃烧特性,采用三步反应动力学机理,建立二维三明治模型,耦合气固两相;对20~80kPa下AP/HTPB的微尺度燃烧进行模拟,并与高压下(4MPa)AP/HTPB燃烧特性差异进行对比。结果表明,亚大气压下BDP模型中第一步反应靠近燃面,放热量较大,在AP/HTPB推进剂燃烧过程中占主导地位;燃烧环境压强不同,导致火焰的特性不同,亚大气压下火焰中扩散与混合过程共存,高压下为扩散火焰;相比于高压,亚大气压火焰离燃面远,面积大;由于高低压下放热区域及放热率差异导致气固相温度分布不同,从而影响燃面形状,亚大气压下AP与HTPB交界处相对于整个燃面突出,而高压下交界处相对于整个燃面凹陷。

Numerical Simulation of AP/HTPB Microscale Stable Combustion under Subatmospheric Pressure

To study the combustion characteristics of ammonium perchlorate/hydroxyl-terminated polybutadiene(AP/HTPB)at subatmospheric pressure,a two-dimensional sandwich model was established by using a three-step reaction kinetics mechanism,coupled with gas-solid phases.The AP/HTPB micro-combustion was simulated at 20-80kPa,and compared with the combustion characteristics of AP/HTPB at high pressure of 4MPa.The results show that the first step reaction in the BDP model is close to the burning surface under subatmospheric pressure,and it has a high heat release,which plays a dominant role in the combustion process of AP/HTPB propellant.Different pressure in the combustion process leads to distinct flame characteristics.Diffusion and mixing processes coexist in the flame under subatmospheric pressure,but only diffusion flame under high pressure.Compared to the high pressure condition,flame under the subatmospheric pressure is far from the burning surface and has a large area.The temperature distribution of gas-solid phases is distinct due to the difference of heat transfer area and heat release rate at high and low pressures,thus affecting the shape of the burning surface.The junction of AP and HTPB under subatmospheric pressure is prominent relative to the whole burning surface,while the junction under high pressure is depressed relative to the whole burning surface.