柔性热膜剪应力传感器水下测量温度修正
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摘要: 柔性热膜微传感器应用于流体壁面剪应力测量时,流体温度对传感器输出有很大影响,因此有必要对工作在非标定温度下的传感器输出信号进行修正补偿。重点研究了水下测量时传感器输出与水温的关系以及温度修正方法。通过分析传感器过热比和流体物理性质与温度的相关性,建立了流体温度与传感器过热比和标定系数的函数关系。在此基础上,提出了一种用于水下剪应力测量的温度修正方法,可以有效减小水温对传感器输出的影响。经实验验证,该方法可以使工作在25℃、28℃水温环境下的传感器输出值与其20℃标定值的相对误差从23.7%和37.1%回落到0.82%和0.83%。Abstract: The fluid temperature difference between practical operation and its original calibra-tion procedure can cause an unacceptable error for micro thermal shear stress sensors.Thus,the temperature correction is necessary when the working water temperature is different from the original calibration temperature.By analyzing the temperature dependence of the overheat ratio and coefficients of the sensor's behavioral equation,a correction method is presented.Laminar flow experiments with changeable temperatures are carried out.The results show that the influ-ence of water temperature can be minimized,and the relative errors of sensor output at water temperature of 25℃ and 28℃ can be falling to 0.82% and 0.83% from 23.7% and 37.1%,re-spectively.
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