Study On Screening Characteristics Of Linear Screen Based On Discrete Element Method

Hydropower is China’s second largest energy source after coal,and it is also the clean energy that can form the largest supply scale among renewable energy sources.Among them,abundant micro-head resources(rivers,canals,reservoirs,power plant tail water,pipeline water supply,urban Wastewater,marine new energy,etc.)Due to relatively low economic benefits,they have not been effectively developed and utilized,and have broad development prospects.How to effectively use micro-head resources and hydropower generation is an important aspect and research of water resources utilization and hydropower technology Subject.In view of the fact that the existing hydroelectric power generation devices are mostly concentrated on potential energy generation,and the kinetic energy of the tidal energy turbines is too large and the starting flow rate is high,etc.,a low-flow head micro-power generation device is designed.The device is composed of a water flow acceleration device,a composite impeller,a generator,and a draft tube.The water flow acceleration device is composed of a water flow gradient diversion cover,a water inlet and a guide vane;the composite impeller is composed of a horizontal axis impeller,an airfoil vertical axis impeller,and a cone tooth group.The main research contents of this article include:(1)Use Bates theory to perform power calculation to obtain the ideal inlet and outlet velocity ratio;select the type of the shroud based on the shroud thrust coefficient;design the horizontal axis impeller and the vertical impeller at the wake based on the leaf element theorem.(2)Design components such as water flow acceleration devices,impellers,etc.based on known data,hydraulic calculations,and power efficiency calculations.After all the dimensions and other data are obtained use these data to use SolidWorks to 3D model the,main components and assemble the overall device.(3)Some parts use the Fluid Flow(Fluent)module of the workbench in ANSYS to extract the fluid domain,divide the grid,and perform the numerical simulation calculation and post-processing of Fluent.According to the hydrodynamic performance analysis results,the structure is optimized to obtain the best overall device.Fluent simulation software is used for overall analysis,and MRF(moving reference frame)model is used to simulate a simplified micro-head low-flow energy collection device.(4)The original prototype was designed to be large and inconvenient for experiments,so a similar laboratory prototype was designed.The scaling ratio between the similar prototype and the original prototype is 1: 3.Using 3D printing technology,the components of similar prototypes of the equipment are obtained,and the experimental similar prototypes are assembled.Similar prototypes were tested in outdoor micro-head low-velocity waters to obtain experimental data,and the experimental data were analyzed to further optimize the design and obtain the optimal experimental prototype.The resulting prototype can be started at 0.45 m / s,reliable power generation at a flow rate of 0.45m/s-2.4m/s,and a power of 350 W at a rated flow rate of 2.0m/s.The micro-head low-flow energy collection device has the advantages of fast manufacturing,easy installation,high comprehensive cost performance,and wide available hydraulic resources.It can be widely used in mountainous waterways,rivers,lakes,reservoirs and other water streams with slower flow rates but more water resources Rich environment.It also provides important theoretical and practical basis for water resources utilization and hydropower technology development.This type of equipment has been successfully applied to the parameter monitoring of an irrigation area,and has a very good application prospect.