A wall shear stress measurement system based on flexible hot film sensor is developed to realize wall shear stress on-line measurement.Through analysis on working principle of flexible hot film sensor,a high precision constant current drive circuit based on LTZ1000 voltage standard is developed,and a 18 bit real differential simultaneous data acquisition module which based on DSP2812 & AD7609 are developed,temperature compensation method is used to revise environmental temperature drift of sensor output signal.System character test indicates that the shear stress measurement system achieves a resolution prior to 0.2 Pa at fluid temperature 10 ～30 ℃,at range 0 ～ 10Pa,and an output signal deviation of system is 0.6 ％/℃,which meet wall shear stress measurement requirement of actual fluid.%为实现流体壁面剪应力在线测量,设计了一种基于柔性热膜传感器的流体壁面剪应力测量系统.通过分析柔性热膜传感器作用机理,研发了基于LTZ1000电压基准的高精度恒流驱动电路,开发了基于DSP2812,AD7609的18位真差分同步高速数据采集模块,并通过温度补偿方法对传感器输出信号进行了环境温漂修正.系统性能测试表明:当流场温度在10 ～30℃范围变化时,剪应力测量分辨率在0～10 Pa范围内优于0.2Pa,流体温度变化引起的系统输出信号偏差为0.6％/℃,满足实际流体壁面剪应力测量要求.
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