With the rapid development of aerodynamics for high speed aircraft, the flight experiments need to be carried out under ultra-high Reynolds number condition to simulate actual high-speed flight conditions, which puts forward higher requirements for the wind tunnel. Reynolds number increases rapidly as the decrease of the flow temperature because the viscosity of the working gas decreases and the density increases. As a result, a pressurized tunnel at cryogenic temperature can provide real-flight Reynolds numbers. Therefore, cryogenic wind tunnel is one of the best testing facilities to rech ultra-high Reynolds number. The thermal insulation system is crucial for the design and operation of the cryogenic wind tunnel. In this paper, the features of an internal insulation system for the cryogenic wind tunnel are firstly highlighted in comparison with traditional insulation systems. The internal thermal insulation system for the cryogenic wind tunnel is discussed. In order to evaluate the thermal insulation performance, the heat transfer calculation for a typical wind tunnel region with the diameter of two meters is carried out using finite element method based on the analyses of the heat transfer conditions. The averaged heat load from the environment is obtained to optimize the liquid nitrogen consumption during the wind tunnel operation. The thickness of the panel should be 150 mm to reach the design target of averaged heat flux 60 W/m². Meanwhile, the typical region is constructed according to the new internal insulation system. Cryogenic test is conducted and it is proven that the new internal insulation system could efficiently prevent the environment heat flow and ensure the normal operation of the cryogenic wind tunnel.

随着高速飞机空气动力学的飞速发展，需要在超高雷诺数条件下进行飞行实验，以模拟实际的高速飞行条件，这对风洞提出了更高的要求。雷诺数随着流动温度的降低而迅速增加，这是因为工作气体的粘度降低并且密度增加。结果，在低温下的加压隧道可以提供真实的雷诺数。因此，低温风洞是获得超高雷诺数的最佳测试设备之一。隔热系统对于低温风洞的设计和运行至关重要。在本文中，与传统的隔热系统相比，首先强调了低温风洞内部隔热系统的功能。讨论了低温风洞的内部隔热系统。为了评估隔热性能，在分析传热条件的基础上，采用有限元方法对直径为两米的典型风洞区域进行了传热计算。获得来自环境的平均热负荷，以优化风洞运行期间的液氮消耗。面板的厚度应为150 mm，以达到平均热通量60 W / m的设计目标 为了评估隔热性能，在分析传热条件的基础上，采用有限元方法对直径为两米的典型风洞区域进行了传热计算。获得来自环境的平均热负荷，以优化风洞运行期间的液氮消耗。面板的厚度应为150 mm，以达到平均热通量60 W / m的设计目标 为了评估隔热性能，在分析传热条件的基础上，采用有限元方法对直径为两米的典型风洞区域进行了传热计算。获得来自环境的平均热负荷，以优化风洞运行期间的液氮消耗。面板的厚度应为150 mm，以达到平均热通量60 W / m的设计目标²。同时，典型区域是根据新的内部绝缘系统构造的。进行了低温测试，事实证明，新的内部隔热系统可以有效地防止环境热流，并确保低温风洞的正常运行。