一、前言 很早就有人应用超声技术来测量流体的流速,但在很长一段时间内,尚未付诸实用。进入七十年代以后,随着工业的发展,以及节能和环境保护等方面的问题的提出,在流量测量领域内,许多新的、困难的课题接踵而至,原有仪表难以适应。由于超声波流量计可以实现非接触测量,能在管 I. INTRODUCTION Early on, some people used ultrasonic technology to measure the flow rate of a fluid, but for a long period of time, it has not yet been put into practical use. Since the 1970s, with the development of industries and the issues of energy saving and environmental protection, many new and difficult problems have come to the fore in the field of flow measurement, making the existing instruments difficult to adapt to. As the ultrasonic flowmeter can achieve non-contact measurement, can be in the tube