激波风洞驻点热流测量误差机理及其不确定度研究

Study on error mechanism and uncertainty assessment of heat flux measurement in shock tunnel

详细分析了测热传感器安装后驻点区曲率变化对局部流场变化和热流变化的影响规律,并根据不同传感器的类型和敏感元件的组成情况,研究给出了修正方法和修正系数;研究了传感器表面温升与热流之间的相互影响关系,对热流实测结果进行了修正。同时,研究了来流流场的微小变化对热流的影响,分析了传感器组成尺寸、人为读数、传感器重复使用等随机因素对热流测量的影响,并结合随机误差分析理论给出了不确定度的评定方法,计算得到了某次热流试验中的测量不确定度。并由此给出了对传感器制作和测热试验方法的改进建议。该文的研究内容有利于进一步提高热流测量精度,为高超声速飞行器的研制提供参考。

The influence of thermal sensors＇ mathematical and physical model and data processing method on the acquisition of heat flux data were analyzed, and the difference between the processed and actual heat flux data was quantitatively presented upon that. The changes of the flow field and wall heat flux caused by the curvature variation of the stagnation region due to the installation of sensors were also discussed in this paper. The correction method and corresponding coefficients were proposed for different types of sensors and different compositions of sensitive elements. The correlation between temperature rise and heat flux variation on the sensor sur- face was studied and the modified formula was given to modify the original data. Moreover, the uncertainty estimation method of aerodynamic heating measurement was established according to different error sources, and the influences of small changes of inflow condition on the heat flux and sensors＇ random factors on heat flux measurement were also analyzed. Based on the random error analysis theory, the uncertainty assessment method was established, based on which the uncertainty of heat flux measurement in the validation experiment was obtained. In conclusion, some valuable results and suggestions about the sensor design and aerothermal experiments were obtained, and these results can improve the accuracy of heat flux measurement further and thus have prominent application prospect in near-space hypersonic vehicle development.