热流传感器传热特性电弧风洞实验及数值模拟

高超声速飞行器面临剧烈的气动加热环境, 电弧风洞是飞行器防热材料地面考核筛选的主力设备。热流密度是电弧风洞重要的模拟参数之一, 需要进行准确有效的测量。针对电弧风洞气流环境特点, 开展传统塞式量热计和新型同轴热电偶的对比测热试验, 并采用数值模拟对两种热流传感器的传热特性进行了分析。在电弧风洞平板自由射流试验热流密度分布在0~1 100 kW/m2范围内, 同轴热电偶的热流密度测试试验结果相对塞式量热计偏低10%~15%。数值模拟结果表明, 塞式量热计本身结构热物性参数不匹配会导致热流密度测量数值偏高至少10%, 而同轴热电偶测量数值偏高最大仅为2.19%, 相对塞式量热计具备更高的测量精度。同时, 电弧风洞中不同材质热流密度测试模型使用同轴热电偶进行测热试验时, 需要在同轴热电偶同模型之间增加适当厚度的不锈钢套以满足传感器周围环境的热匹配。 

Experimental and Numerical Simulation of Heat Transfer Characteristics for Heat Flux Sensors in Arc Heated Wind Tunnels

Hypersonic aircrafts need to endure extremely critical aerodynamic heating environment. Arc heated wind tunnels are the main facilities for ground assessment and filtration of thermal protection materials. Heat flux is one of the important simulation parameters of the arc heated wind tunnel, which needs to be measured accurately and effectively. Based on the characteristics of the flow in the arc heated wind tunnel, comparison measurement tests on heat flux of traditional slug calorimeter and coaxial thermocouple have been carried out. The numerical simulation on the heat transfer characteristics of the above two heat flux sensors has also been analyzed. For the plate free jet tests in arc heated wind tunnel with heat flux range of 0~1 100 kW/m2, the heat flux test results of coaxial thermocouple are 10%~15% lower than those of slug calorimeter. The numerical simulation results indicate that the heat flux measurement value of the slug calorimeter is at least 10% higher, which is caused by the thermal physical parameters mismatch of its structure. While, the coaxial thermocouple has better measurement accuracy and the maximum measurement value deviation is only 2.19%. When coaxial thermocouple is used in the heat flux test models of different materials in arc heated wind tunnel, a stainless-steel sleeve of appropriate thickness should be added between coaxial thermocouple and models to meet the thermal matching of the surrounding environment beside the sensor.