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第27届全国中学生物理竞赛预赛第18题所描述的超声波测量方法用到的就是时差式超声波流速计,其原题为:超声波流量计是利用液体流速对超声波传播速度的影响来测量液体流速,再通过流速来确定流量的仪器.一种超声波流量计的原理示意如图1所示.在充满流动液体(管道横截面上各点流速相同)管道两侧外表面上P_1和P_2处(与管道轴线在同一平面内),各置一超声波脉冲发射器T_1、T_2和接收器R_1、R_2.位于P_1处的超声波脉冲发射器T_1向被测液体发射超声脉冲,当位于P_2处的接收器R_2接收到超声脉冲时,发射器T_2立即向被测液体发射超声脉冲.如果知道了超声脉冲从P_1
The 27th National Physics Contest Preliminaries 18th chapter describes the ultrasonic measurement method used is the time difference ultrasonic anemometer, its original title: Ultrasonic flowmeter is the use of liquid flow velocity on the ultrasonic propagation velocity to measure the liquid flow rate, And then through the flow rate to determine the flow of the instrument.A schematic diagram of the ultrasonic flow meter shown in Figure 1. In the flow of liquid (the same cross-section of the pipe at the same flow rate) on both sides of the outer surface of the pipe P_1 and P_2 Department Axis in the same plane), each set an ultrasonic pulse transmitter T_1, T_2 and receiver R_1, R_2 located at P_1 ultrasound pulse transmitter T_1 to the measured liquid emission ultrasonic pulse, when located at P_2 receiver R_2 receive To the ultrasound pulse, the transmitter T 2 immediately emits an ultrasonic pulse to the measured fluid.If you know the pulse from P_1