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

The influence of thermal sensors’mathematical and physical model and data pro-cessing 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 correspond-ing coefficients were proposed for different types of sensors and different compositions of sensi-tive 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.