高精度矿用超声波风速测量仪设计

Design of high precision mine ultrasonic anemometer

  • 摘要: 针对现有风速测量仪的最低测量风速不能满足矿井低风速条件下精准测风需要的问题,基于超声波时差法风速测量原理,设计了一种具有低启动风速的高精度矿用超声波风速测量仪。采用2个超声波发射探头和2个接收探头交错设置,形成2个超声波传播通路,分别测定超声波在特定风速场中的顺风和逆风传播时间,利用超声波在空气中的传播速度与风流速度的叠加效应,求解发射和接收探头间的平均风速(温度对风速测量的影响可以忽略不计)。为分析超声波探头方向对测量准确性与可靠性的影响,采用4种不同探头布置方式进行实验,结果表明,超声波探头方向错位越严重,风速标准差和波动范围越大,因此,采用红外定向装置校准风速测量仪安装位置,以减小超声波探头方向错位引起的测量误差。选用滑动平均法对原始风速波形曲线进行平滑处理,以消除随机噪声,提高输出风速的稳定性。通过分析测量精度影响因素,确定超声波发射频率为40 kHz,待机时间为100 ms。理论计算和实验结果表明:该风速测量仪的分辨率为0.01 m/s,测量误差为±0.1 m/s,启动风速低于0.1 m/s,可以满足矿井低风速巷道的精准测风要求。

     

    Abstract: The minimum measured wind speed of the existing anemometer can not meet the requirements of precise wind measurement under the condition of low wind speed in mines. In order to solve this problem, based on the principle of ultrasonic time difference method wind speed measurement, a high-precision mine ultrasonic anemometer with low starting wind speed is designed. Two ultrasonic transmitting probes and two ultrasonic receiving probes are arranged alternately to form two ultrasonic propagation paths. The downwind and upwind propagation times of ultrasonic waves in a specific wind speed field are measured respectively, and the average wind speed between the transmitting probes and the receiving probes is solved by using the superposition effect of the propagation speed of ultrasonic waves in the air and the wind speed (the effect of temperature on the wind speed measurement can be ignored). In order to analyze the effect of ultrasonic probe direction on the accuracy and reliability of measurement, four different probe arrangement modes are used to carry out the experiment. The results show that the more serious the ultrasonic probe direction dislocation is, the larger the standard deviation and fluctuation range of wind speed. Therefore, the infrared orientation device is used to calibrate the installation position of the anemometer to reduce the measurement error caused by the ultrasonic probe direction dislocation. The moving average method is used to smooth the original wind speed waveform curve to eliminate random noise and improve the stability of output wind speed. By analyzing the factors affecting measurement precision, it is determined that the ultrasonic emission frequency is 40 kHz and the standby time is 100 ms. The theoretical calculation and experimental results show that the resolution of the anemometer is 0.01 m/s, the measurement error is ±0.1 m/s, and the starting wind speed is lower than 0.1 m/s, which can meet the precise wind measurement requirements of the mine roadway with low wind speed.

     

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