Abstract Drawn on the experience of the heat-flow-meter method, an experimental system is designed, established and validated to investigate the thermal insulation performance of SiC opacifier doped silica aerogel at large temperature difference. The test section of the experimental system is a symmetrical sandwich-structure, while the temperature of the cold surface keeps constant by circulating the water from the thermostat, NESLAB ThermoFlex2500, and the hot surface is electrically heated. Compared with the traditional method of the back-surface temperature response, the cold surface temperature is quantitatively controllable. Based on the present experimental system and method, the thermal insulation performance of insulator can be qualitatively and quantitatively evaluated by analyzing the temperature responses of the hot surface through the whole heat transfer process including the initial steady-state, the unsteady-state, and the final new steady-state. Qualitatively, the higher the temperature of the hot surface is and the faster the temperature rise of the hot surface is, the better the thermal insulation performance of the material has; quantitatively, the effective thermal conductivity of the materials is obtained based on the semi-infinite medium model and Fourier's Law. The present results show that the effective thermal conductivities of silica aerogel doped by 3.5 μm SiC opacifier with different volume fraction of 0%, 1%, and 5.84% are about 0.02559 W m−1 K−1, 0.02844 W m−1 K−1, and 0.03305 W m−1 K−1, respectively, at small temperature difference ( 400 K), the thermal insulation performance of silica aerogel doped by 3.5 μm SiC particle with a volume fraction of 1% is good enough, though 3.5 μm SiC particle with a volume fraction of 5.84% has a marginal improvement in blocking the thermal radiation within silica aerogel.

中文翻译：

---

大温差下SiC遮光剂掺杂二氧化硅气凝胶绝热性能的实验研究

摘要 借鉴热流计法的经验，设计、建立并验证了实验系统，以研究大温差下SiC遮光剂掺杂二氧化硅气凝胶的隔热性能。实验系统的测试部分是一个对称的夹层结构，而冷面的温度通过循环来自恒温器NESLAB ThermoFlex2500的水保持恒定，而热面则是电加热。与传统的背面温度响应方法相比，冷面温度是可定量控制的。基于现有的实验系统和方法，通过分析热面在整个传热过程（包括初始稳态、非稳态和最终新稳态）的温度响应，可以定性和定量地评价绝缘子的隔热性能。定性地，热面温度越高，热面温升越快，材料的隔热性能越好；基于半无限介质模型和傅立叶定律，定量得到材料的有效导热系数。目前的结果表明，掺杂不同体积分数 0%、1% 和 5.84% 的 3.5 μm SiC 遮光剂的二氧化硅气凝胶的有效热导率约为 0.02559 W m-1 K-1、0.02844 W m-1 K- 1, 和 0.03305 W m−1 K−1,