Flow characteristics and diaphragm deformation of pressure‐compensating drip irrigation emitters*

Abstract

AbstractPressure‐compensating (PC) emitters are extensively utilized because they can enhance the irrigation uniformity and the terrain adaptability of drip irrigation systems. To examine the interaction between the elastic diaphragm and fluid of PC emitters, the internal flow behaviour and the diaphragm deformation of PC emitters were studied by one‐way and two‐way fluid–structure interaction (FSI) numerical simulation methods. The deformation characteristics of the elastic diaphragm, the change of the outflow section around the outlet of the pressure‐compensating chamber, and the pressure and velocity distribution of the flow field were analysed in this study. The results illustrate that the deformation process of an elastic diaphragm during the entire working process could be divided into three phases: rapid deformation, slow deformation, and long‐term tiny deformation. After the diaphragm contacted convex land, the overflow groove was the only channel where water could flow out of the PC emitters; and as working pressure increased, the increment of the diaphragm deformation was extremely tiny. However, it was the tiny deformation of the elastic diaphragm that maintained the flow rate of the PC emitters constant over a wide range of working pressures. The results can provide references for exploring the pressure‐compensating mechanism of PC emitters and their optimal design.