为了解决自由装填大长径比火箭发动机装药高温工作时的碎药问题,以一种螺压改性双基推进剂装药为研究对象,采用固体火箭试验发动机研究了影响自由装填大长径比发动机装药工作稳定性的因素,包括初始通气参量(æ)、挡药架厚度(d)、装药局部涂覆。结果 表明,装药结构是影响自由装填大长径比发动机装药工作稳定性的主要因素,减小初始通气参量(æ)能显著提高装药在高温条件下的工作稳定性。对于长径比为12的推进剂装药,50℃时,æ从225减小至166,基本消除了碎药的产生; 60℃时,显著减小了碎药的产生; 采用厚度为25mm的挡药架比采用厚度为8mm的档药架更有利于减少装药工作时碎药的产生; 装药内孔是否涂覆对改善装药工作时的碎药情况没有作用,不影响装药工作的稳定性。
In order to solve the cracking problem of free loading in solid rocket motor grains with large aspect ratio at high temperature operation, taking a modified double-based propellant grain with screw extruded process as the research object, the factors influencing the working stability of free-loading screwed extruded CMDB propellant with large aspect ratio grains were investigated by solid rocket motor test. These factors include initial aerate parameter(æ), the thickness of bracket(d), inner hole coating. The results show that the structure of grain is the major reason which affects the working stabilility of free loading propellant grains with large aspect ratio, working stability can be improved obviously by reducing æ. For propellant grains with large aspect ratio of 12, æ reduced from 225 to 166, and the cracking problem disappears at 50℃ and is improved obviously at 60℃. It is benefit to improve the cracking problem of the propellant grains by increasing the thickness of bracket from 8mm to 25mm. The working stabilility of the propellant grains has no change with or without inner hole coating.
