Development of high accurate environmental flow measurement system using ultrasound

饮用水和农业用水来自河流、湖泊和水库。最近，来自工厂的生活废水和微生物的繁殖造成的水污染正在恶化，特别是在亚洲。针对这一环境问题，需要开展国际间的研究合作，开发综合性的水污染控制技术，本文报道了高精度测量的超声多普勒法在环境水流中的应用研究。该方法使用脉冲超声回波描记术连同检测到的瞬时多普勒频移来形成速度轮廓。将该方法测得的流速剖面与电磁海流计测得的流速剖面进行了比较，得到了相似的流速剖面。由于超声多普勒法是一种直线测量方法，因此在两条测量线的交点上可以得到二维速度矢量。利用RTK-GPS对传感器进行精确设置，形成二维水流图，并将超声多普勒法应用于某河流水流环境监测中。实测的流速剖面表明，河流中的微粒足以反射超声回波，超声多普勒法和电磁流速计的平均流速剖面吻合较好。通过应用RTK-GPS获取传感器位置信息，利用超声多普勒法和RTK-GPS进行二维流场成像，得到的矢量场清晰地显示了河流的流量。

Drinking and agricultural water is supplied from rivers, lakes, and reservoirs. And recently, water pollution with domestic wastewater, from factories, and slack and the propagation of microbes is worsening especially in Asia. For this environmental problem, international study cooperation and the development of comprehensive technologies for water pollution control are demanded.In the present study, the investigation on the application of ultrasonic Doppler method with high accuracy measurement to the environmental flow is reported. This method uses a pulsed ultrasonic echography together with detected instantaneous Doppler shift frequency to form a velocity profile. Velocity profiles measured by this method and the Electromagnetic Current Meter were compared, and similar profiles were obtained. Since Ultrasonic Doppler Method is a line measurement, a two-dimensional velocity vector can be obtained on the crossing point of two measuring lines. And by setting up the transducer accurately using RTK-GPS, a two-dimensional flow mapping can be formed.Ultrasonic Doppler method was applied to a river flow in order to apply to Environmental flow mapping. The measured velocity profiles show that microparticles in the river are enough to reflect the ultrasonic echo, and mean velocity profiles from Ultrasonic Doppler method and Electromagnetic Current Meter agree well. By applying RTK-GPS to obtain the information of the transducer position, the vector field by two-dimensional flow mapping using Ultrasonic Doppler method and RTK-GPS shows clearly the river flow.