Numerical simulation of the effects of sandy water on regulator labyrinth channel in micro-sprinkler systems

Abstract

The effects of sandy water on the W-shaped labyrinth channel of micro-sprinkler irrigation systems with large flowrate were investigated using Computational Fluid Dynamics (CFD). Using ANSYS FLUENT software and different inflow conditions (e.g., pressure, velocity, sediment concentration, and sand particle diameter), internal turbulent multiphase flow and sand deposition were simulated by the Eulerian multiphase flow model. Particle erosion in the labyrinth channel was calculated by the Discrete Phase Model (DPM). The results show that vortex movements and shear actions at the boundary layer cause self-flushing in the channel. The location of sand particle deposits and the turbulent dissipation rate are related to the operating pressure, which is optimal at 300 kPa. The erosion rate of the channel wall is proportional to the inflow sediment concentration but has no obvious relationship with inflow velocity. Based on the movement regulation of sand particles in the labyrinth channel, recommendations on filtration requirements and operating pressure of irrigation systems are proposed. HIGHLIGHTS Sand deposition in the W-shaped labyrinth channel is simulated with the Eulerian model.; There exists an optimal pressure to control the sands deposit location.; Particle erosion in the channel is simulated with Discrete Phase Model.; Erosion rate of sand particles is proportional to the sediment concentration.;

Keywords

• dpm
• labyrinth channel
• micro-sprinkler irrigator
• multiphase flow simulation
• sand deposition and erosion