非线性热环境下高温合金蜂窝板隔热性能研究

RESEARCH ON HEAT-SHIELDING PROPERTIES OF SUPERALLOY HONEYCOMB PANEL FOR NON-LINEAR HIGH TEMPERATURE ENVIRONMENT

金属蜂窝板结构在高温热环境下的隔热特性是高速飞行器热防护设计的重要参数.使用自行研制的高速飞行器瞬态气动热试验模拟系统,对高温合金蜂窝平板结构在高达800℃的非线性热环境下的隔热性能进行实验研究,获得了蜂窝板结构的瞬态和稳态传热特性以及在多利不同温度下金蜂窝平板结构隔热效果的实验数据.在考虑结构内部蜂窝芯壁面间辐射、金属结构的传热以及蜂窝腔内空气传热的多重热交换条件下,采用三维有限元计算方法对蜂窝板的隔热特性进行了数值模拟,计算结果和试验结果的吻合性良好,验证了数值模拟方法的可信性和有效性,并为数值模拟方法能够在一定程度上较好地替代价格昂贵的气动热模拟试验打下了基础.讨论了在复杂非线性高温环境下金属蜂窝板隔热效率的变化,加热面温度的升降速度与隔热效率的关联性以及金属蜂窝板表面发射率的选取等问题,对高速飞行器金属蜂窝结构的热防护研究具有重要的参考价值.

The heat-shielding characteristics of metallic honeycomb panel structure （MTPS） in high temper- ature environments are very important parameters for thermal protection design of high-speed aircrafts. Using the self-developed transient aerodynamic heating simulation system designed for high-speed aircrafts, the heat- shielding performance of MTPS in the non-linear high temperature environment up to 800℃ was experimentally investigated. The heat-transfer characteristics of MTPS at transient and steady states, and the heat insulation effects at various temperatures, were obtained. Also, by carefully considering the multiple heat exchange including the radiation among the inside honeycomb walls, the heat transfer of the metal structure and the heat transfer of the air within the honeycomb cavity, a three dimensional finite element model was established to simulate the heat-shielding performance of the honeycomb panels. The numerical simulations agree well with the experimental results, verifying the correctness and effectiveness of the numerical simulation method. The good agreements also confirm the feasibility of substituting expensive air thermal simulation testing using numerical simulation. Some other key issues, such as heat shielding efficiency variation of the MTPS in complex non-linear high temperature environment, the relutionship among the heat shielding efficiency, the change speed of front surface temperature and selection of emissivity for the MTPS＇ surface, were also discussed in this work, which provide important references for the heat-shielding of MTPS to be used in high-speed crafts.