流量传感器的制备及检测电路的研制

本文介绍了一种利用流体的热效应来测量流体流速的热式传感器。由两个二极管组成的电桥电路为测量探头，一定温度的流体以不同流速流过测量探头，使测量探头周围产生不同的温度场，转换为电压进行输出。放大输出电压，A／D转换成数字信号，单片机处理后通过数码管显示出来。流体流速与输出电压进行非线性拟合，得到流体流速与电压的函数关系式，最终通过采集到的任意输出电压值求得对应流量值。输出电压值与流体环境温度也有关。输出电压与流速，及输出电压与环境温度的关系通过归十法拟合出来，它依据多次迭代结果得到一个允许误差范围的电压-流量、电压-温度的反演拟合多项式。

Developments of the flow sensors and the detection circuits

A method for measuring the fluid flow based on the thermal effect is introduced. Two diodes form an electric bridge circuit to serve as measuring probe. The fluid flow at certain temperature flowing through the measuring probe with different flow velocities will make different temperature fields produced around the probe. The temperature field differences can be transferred into voltage outputs, which are amplified, A/D converted, processed by MCU and displayed on the LED. Non-linear fitting is done to get the function relation between flow velocities and output voltages, by which the flow velocities are obtained after the corresponding voltage values are collected finally. The output voltage values are related with the temperatures of the fluid flow too. The relationships between flow velocities and output voltages, flow velocities and temperatures can be fitted by using Ten-Normalized Algorithm . After numerous iteration computing, the fitting polynomial with a permissible error are gotten.