Research progress in analysis of flow passage in irrigation emitters using Computational Fluid Dynamics techniques

Emitter is one of the key parts in micro-irrigation system. The flow-field distribution in emitter flow-passage determines the hydraulic characteristics of the emitter. It is a new way to use the computational fluid dynamics(CFD) approach to analyze exactly the flow characteristics of emitters. This paper reviews the CFD method in the research of hydraulic characteristics of emitter flow-passage, and points out the problems existing in the current numerical model, boundary condition, flow mechanism and flow behavior of micro-scale fluid-field obtained by using PIV equipment. Some numerical examples were presented. The possible factors that affect the simulation precision of emitter CFD analysis were evaluated. It is put forward that the microfluid theory should be adopted to establish the numerical model, and the unsteady method and low-Raynolds approach should be used to calibrate the model parameters of emitter flow-field.