亚洲一区欧美在线,日韩欧美视频免费观看,色戒的三场床戏分别是在几段,欧美日韩国产在线人成

Emitter clogging is one of the obstacles that limits the application and popularization of drip irrigation technology. The computational fluid dynamic (CFD) method was regarded as the most effective method to research the water and sand movement in the labyrinth path of the drip irrigation emitter. Based on the highfrequency pulse with the same parameters (period and amplitude), and the jet tee was used as the boundary condition, and CFD software was used to simulate twophase flow sand concentration in labyrinth channel irrigator in order to improve emitter anticlogging performance. The k-ε turbulence model and Eulerian multiphase flow model were used to simulate the relationship between flow rate and pressure, the instantaneous distribution of particulate matter concentration under high frequency pulse condition, and the influence of high frequency pulse condition on the variation of particulate matter concentration in sediment area. The results showed that the high frequency pulse wave had a great influence on the average flow rate and anticlogging performance of the emitter, and the fluctuation and continuity of the high frequency pulse wave played a major role in the anticlogging ability of the emitter; the order of the high frequency pulse wave of anticlogging ability in descending order was sinusoidal wave, triangular wave, trapezoidal wave and rectangular wave; increasing inflow concentration would lead to sediment deposition in the vortices, and high frequency pulse wave can increase the erosion of the vortices to improve the blockage resistance. The concentration of each part of the emitter was increased with the increase of particle size, and the concentration distribution and variation were slightly different under different particle sizes. The research result can provide theoretical reference for the application and popularization of the drip irrigation system with high frequency pulsed flow.