关键词: 水动力学, 流量控制, PLC, 控制系统

Abstract: Aiming at the problem of flow measurement when the channel flow is large and the flow conditions are complex, a channel flow calculation method based on hydrodynamic model is proposed, and a channel flow control system based on hydrodynamic model is established according to this method. First, establish the hydrodynamic mathematical model, and calculate the channel flow using the twopoint water level measurement method, that is, select two sections at the upstream and downstream of the gate, use two water level sensors to measure the section water level data in real time, use the upper computer to solve the flow control equation to obtain the flow of the two sections, and take the average value of the flow of the two sections as the flow value of the channel. Secondly, the channel flow control system is built with PLC to control the opening and closing of the gate according to the dispatching requirements, so as to achieve accurate control of the channel flow. In the case of increasing water supply flow and complicated water flow conditions, the average deviation rate of the calculated flow is less than 5% compared with the data measured by multichannel ultrasonic flowmeter. The experimental research shows that the flow control error of the control system is 0.514%, the system response time is less than 200 ms, and the systems mean time between failures is more than 10 000 hours. The research of control system provides theoretical basis and case support for the future construction of channel flow scheduling project, and has strong application value.

Key words: hydrodynamics, flow control, PLC, control system