浮动式剪应力微传感器的标定

Calibration of the Floating Element Shear Stress Micro-Sensor

流体壁面剪应力微传感器的精确标定是进行流动测量的基础。分别采用自重加载、离心加载和风洞吹风三种不同方法,对基于电容检测原理的浮动单元剪应力微传感器进行标定与实验研究。对比了三种实验方法和标定的结果,分析了标定过程中的设备、传感器的加工及安装等误差的影响。研究结果表明,标定的传感器灵敏度为30 mV/Pa,三种标定方法的误差在2%以内,采用离心加载标定的误差最小;为进一步减小标定误差提供了改进方法。利用标定后的传感器,在风洞中对标准翼型的定点壁面剪应力值进行了测量,与仿真结果进行对比,二者能够较好吻合。

The accurate calibration of the flow wall shear stress micro-sensor is the basis of the flow measurement. Three different methods including the self gravity load, centrifugal load and wind tunnel experiment were carried out to calibrate and study the floating element micro-shear stress sensor based on the capacitance detection principle. Three experimental methods and cali- bration results were compared, and the errors caused by the equipment, sensor fabrication and mounting were analyzed. The results indicate that the calibration sensitivity of the sensor is 30 mV/Pa with the calibration error less than 2 %. The calibration error by the centrifugal load is minimal, reducing the calibration error. The wall shear stress of a standard airfoil was measured in the wind tunnel. And the measured result is in good agreement with the simulation result.