材料期刊网

为满足高超声速飞行器防热设计中对烧蚀温度场的计算要求,建立了适用于高超声速飞行器防热复合材料的烧蚀传热计算方法,通过算例将烧蚀温度场计算结果与简化模型和试验结果进行了对比,验证了计算方法的合理性.进而运用该方法分析了长时间中低热流加热和短时间高热流加热两种特定热环境下的热导率、密度、表面发射率、动态热解等因素对烧蚀传热的影响规律.结果表明各个因素对烧蚀传热行为的影响程度不同.其中热导率对防热材料内部温度的影响最大,表面发射率对材料表面温度的影响较大,对内部温度的影响程度与时间相关;热解动力学参数中活化能对材料内部温度有一定的影响;活化能和热导率对材料热解碳化过程的影响较为显著.研究结果为烧蚀传热计算精度的进一步提高提供了参考价值.

As the accuracy of the ablation temperature field calculation of thermal protective composite materials was not high, a calculation method was established to analyze the carbon-based and silicon-based thermal protective material under specific thermal environment.Comparing the ablation temperature results with the simplified model and ground test results, the method in this study was proved to be reasonable.Several thermal parameters, thermal conductivity, density, surface emissivity, pyrolysis and carbide, were studied under specific thermal environment to analyze the influence law of the factors on the ablation heat transfer.The results show that the influence of various factors on the ablation heat transfer behavior is different.The thermal conductivity and the emissivity has a major contribution to the influence on internal and external temperature of the thermal protective material, respectively.The influence of the emissivity on the internal temperature is time-dependent.The activation energy has a certain impacts on the internal temperature of the material.Both the activation energy and thermal conductivity has significant impacts on the material pyrolysis carbonization process.The results provide an important theoretical basis to the correction of the ablative heat transfer calculation method.