Thermal insulation materials are widely used in the fields of thermal protection and the energy conservation at high temperature. Thermal conductivity is one of the most important parameters of characterizing the thermal insulation performance of thermal protection materials. Steady state method such as the guarded hot plate method is normally considered as the most accurate method to measure the thermal conductivity of thermal insulation materials, but the temperature range is limited to below 1000 K. Unsteady state method can be employed at higher temperature but the accuracy is lacking of validation. Consequently, thermal verification experiments are usually conducted by heating the front surface of thermal insulation materials to a very high temperature. However, it is difficult to obtain the temperature-dependent thermal conductivity by using the thermal insulation performance measured with a large temperature difference across the material. In this study, a sandwich structure experimental system is built to carry out the thermal insulation performance tests with a large temperature difference at both steady state and transient state. Both uniform temperature layer method and polynomial fitting method are adopted to extract the temperature-dependent thermal conductivity from the large temperature difference test at steady state. A new transient state identification method is proposed based on the niche genetic algorithm to identify the relation between thermal conductivity and temperature from the transient thermal response. The temperature-dependent thermal conductivity of four thermal protection materials are finally obtained. The identification results prove that the proposed transient identification method is reliable and robust.

保温材料广泛应用于热防护和高温节能领域。导热系数是表征热防护材料隔热性能的最重要参数之一。稳态法如防护热板法通常被认为是测量绝热材料热导率最准确的方法，但温度范围限制在 1000 K 以下。 非稳态法可在较高温度下使用，但准确性缺乏验证。因此，热验证实验通常是通过将隔热材料的前表面加热到非常高的温度来进行的。然而，很难通过在材料的大温差下测量的绝热性能来获得与温度相关的热导率。本研究搭建了夹层结构实验系统，开展稳态和瞬态大温差下的保温性能测试。采用均温层法和多项式拟合法从稳态大温差试验中提取温度相关的热导率。提出了一种基于生态位遗传算法的瞬态识别新方法，从瞬态热响应中识别热导率与温度之间的关系。最终得到四种热防护材料随温度变化的热导率。识别结果证明所提出的瞬态识别方法是可靠和鲁棒的。