装药尺寸及结构对HTPE推进剂烤燃特性的影响

利用自行设计的烤燃实验装置,对HTPE推进剂小尺寸烤燃试样分别进行了升温速率为1、2℃/min的烤燃实验,以此为基础,建立了小尺寸烤燃试样和固体火箭发动机的三维计算模型,利用Fluent软件分别对两者不同升温速率下的烤燃行为进行了数值模拟计算,研究了小尺寸烤燃试样与固体火箭发动机的装药尺寸及结构差异对HTPE推进剂烤燃响应特性的影响。结果表明,HTPE推进剂的烤燃响应时间、响应温度随升温速率的变化趋势与装药尺寸及结构无关,但响应时间和响应温度的绝对值与装药尺寸及结构均有很大关系,升温速率为3.3℃/h(0.055℃/min)时,小尺寸烤燃试样的响应时间为40.3h,响应温度为158℃,而固体火箭发动机响应时间为28.83h,响应温度为120.13℃。推进剂装药尺寸及结构对烤燃点火位置有明显影响,进而影响到烤燃速度范畴的区分,小尺寸烤燃试样慢烤升温速率不大于2℃/min,而固体火箭发动机慢烤升温速率为小于0.5℃/min。因此,对快速、慢速烤燃的严格划分,必须结合装药尺寸、装药结构及推进剂种类等因素进行。升温速率对固体火箭发动机存在热积累临界位置效应,本研究条件下影响热积累临界位置的升温速率为0.5℃/min。

Influences of Charging Size and Structure on Cook-off Characteristics of HTPE Propellant

A cook-off test of small size cook-off sample with HTPE propellant at heating rate of 1 and 2℃/min was conducted by using self-designed cook-off test apparatus.On this basis, three-dimensional calculation models about small size cook-off sample and solid rocket motor were established.The numerical simulation and calculation of their cook-off behaviors at different heating rates were conducted by Fluent software.The influences of the differences of charging size and structure between small size cook-off sample and solid rocket motor on the cook-off response characteristics of HTPE propellant were researched.The results show that the change trend of cook-off response time or temperature along with heating rate has nothing to do with charging size and structure, but the absolute values of response time or temperature have great relationship with charging size and structure.The response time and temperature of small size cook-off sample are 40.3h and 158℃ at the heating rate of 3.3℃/h(0.055℃/min), but the solid rocket motor are correspondingly 28.83h and 120.13℃.Charging size and structure of propellant have obvious effect on the ignition positions of cook-off, and then affect the distinction of cook-off range of heating rate.The slow cook-off heating rate of the small size cook-off sample is not more than 2℃/min,while the solid rocket motor is correspondingly less than 0.5℃/min.Therefore, factors such as charging size, charging structure and kinds of propellant must be considered in the strict partition of fast and slow cook-off.Solid rocket motor has heat accumulation critical position effect about heating rate, and the heating rate of heat accumulation critical position is 0.5℃/min under the condition of this study.