固化降温工艺对固体发动机药柱温度场和结构完整性的影响

Influence of cooling process during curing on temperature field and structural integrity of SRM grain

固化降温工艺对固化降温过程固体发动机药柱的温度场和应力场有显著影响。为准确评估固化降温过程固体发动机药柱的结构完整性水平,优化固化降温工艺,采用数值模拟方法对某碳纤维复合材料壳体发动机药柱在6种固化降温工艺条件下的温度场和结构完整性进行计算,计算过程考虑壳体表面对流换热系数的动态变化和热辐射效应,极大提高了降温过程热载荷引起的药柱结构响应的计算精度。计算得到了不同工艺条件下药柱的温度场及变化规律、应力应变响应规律,评估了药柱的结构完整性。结果表明,通过监测壳体表面温度,并结合温差变化规律和药柱温度平衡时滞可估算药柱内的温度及其平衡时间。通过调整降温工艺参数,可提高药柱的安全系数。降温初期缓慢降温可降低药柱应力应变增长速率,同时可降低药柱的累积损伤水平。

The cooling process during curing has a significant influence on the temperature and stress fields of SRM grain.In order to accurately evaluate the structural integrity level of SRM grain during cooling process,and optimize the cooling process during curing,a numerical simulation method was used to calculate temperature field and structural integrity of a carbon fiber composite case motor grain under six kinds of cooling process conditions,and the dynamic changes of convective heat transfer coefficient and thermal radiation effect on the case surface was considered,which greatly improves calculation accuracy of structure response of the grain caused by thermal load during the cooling process.The temperature field and variation law of the grain under different process conditions,as well as the stress-strain response law was calculated,and the structural integrity of the grain was evaluated.The results indicate that the temperature in the grain and the equilibrium time can be estimated by monitoring the case surface temperature,combined with the variation law of temperature difference and the grain temperature equilibrium time delay.More importantly,the safety factor of the grain can be improved by adjusting the cooling process parameters,slow cooling in the initial stage can reduce the growth rate of stress and strain,as well as the cumulative damage level of the grain.