In order to improve the effective utilization of agricultural irrigation water and to reasonably allocate water resources in irrigation areas, it is necessary to use open channel flow measurement devices that are accurate and easy to carry. In this study, a spring-plate flow measurement device with different plate widths was designed. Through a combination of theoretical analysis and numerical simulation, the measurement characteristics of the device in specific channels under conditions of 20–105 m3/h flow were studied, the relationship between the flow rate and the force acting on the plate surface was fitted, and the hydraulic characteristics of water flow during its use, such as pressure, velocity distribution, and head loss, were analyzed. The results show that in the process of using the spring-plate flow measurement device, the force on the plate surface increases with the increase in the flow rate, and the force on the plate surface is related to the flow rate in the channel by a power of 5/6. The width of the measurement plate impacts the accuracy of flow measurement, and the smaller the plate width, the larger the error in flow measurement. The distribution of pressure on the measurement plate is similar to that of static pressure, and the pressure increases with the increase in the width of the measurement plate. The upstream flow velocity of the device is small, and the water level increases due to obstruction of the measurement plate. When it connects to the downstream water surface, the water level rapidly decreases, and the flow velocity increases. In using the spring-plate flow measurement device to measure flow, head loss will be produced, and the magnitude of this loss increases with the increase in the width of the measurement plate. The research results provide a theoretical basis for the application of spring plate flow-measuring devices in irrigation areas.

Hydrocyclone with guide vanes is one type of swirl flow launching device without energy input. For researching the flow characteristics of that hydrocyclone, the flow distribution of the sections and their variation along the flow were studied using numerical simulation and physical experiment. In addition, the flow field was convenient to be divided into three-dimensional velocities: axial velocity, circumferential velocity, radial velocity and the static pressure. The result showed that the water flow had obvious diversion by the effect of guide vanes. The axial velocity varied into the distribution of higher values emerging away from the pipe wall and the surfaces of guide vanes, and the value was higher on downstream surfaces than upstream surfaces of the guide vanes. The radial velocity’s direction pointed at the axis of pipe on upstream surfaces, and pointed at the pipe wall on the downstream surfaces of the guide vanes; the influenced range was larger in sections along the flow. The circumferential velocity increased along the flow, closing the distorted guide vanes; the value of that velocity was larger closer to the guide vanes, especially the downstream surfaces of the guide vanes. The static pressure decreased along the flow, and the value was larger on the upstream surfaces than the downstream surfaces of the guide vanes. The results can provide some theory references to improve the construction of the hydrocyclone.

To investigate the influence of the guide vane height on the cyclonic flow characteristics of guide vane cyclones, this paper mainly adopts a combination of numerical simulation and physical experiments, taking the guide vane height as the research object, analysing the internal spiral flow generation law through the flow velocity distribution in each section of the cyclone and the change trend along the course and comparing the tangential velocity, radial velocity and axial velocity characteristics of the cyclone at different guide vane heights. The results show that the tangential velocity increases with the increase in the guide vane height on the cyclone and then decreases. When the ratio between the height of the guide vane and the inner radius of the cyclone is in the range of 0.5–0.7, a higher−strength and more stable spiral flow can be produced, and the tangential velocity reaches the maximum when the guide vane height is 30 mm and the height−to−diameter ratio is around 0.6. As the height of the guide vane increases, the radial velocity area towards the wall of the tube increases, while the radial velocity area towards the tube axis decreases. The overall distribution of axial flow velocity is similar to that of turbulent flow in a circular tube, and the velocity increases with increasing height of the guide vane. The conclusion of this paper provides a theoretical basis for further optimisation of the cyclone structure parameters.