Numerical simulation and structure optimization for hydraulic performance of perforated drip irrigation emitters

The perforated drip irrigation emitter (PDIE) is a novel drip irrigation emitter incorporating multiple energy dissipation mechanisms, chiefly hedging, deflection, and friction. To characterize the influences of structural parameters and vortices on the hydraulic performance of PDIE, the emitter discharge exponent, emitter discharge rate, and emitter unit constant were analyzed via hydraulic performance experiments and numerical simulation. The key findings are as follows: (1) Discharge exponents of PDIE ranged from 0.478 to 0.515; average high-pressure hydraulic performance exceeded low pressure by 4.882%. (2) The four key structural parameters that impacted hydraulic performance from large to small are as follows: the width of the perforation (a), the angle of the scalariform perforation plate (alpha), the distance of the two perforations (b), and the length of the channel cavity (c). Among them, the emitter discharge exponent changes significantly with a and alpha. (3) Vortex-retaining PDIE exhibited a lower emitter discharge exponent versus vortex-removed versions. However, vortices increase the emitter discharge rate and reduce the energy consumption of PDIE. After optimization, the emitter discharge exponent of the PDIE with the reserved vortex area is 0.461, which is relatively improved by 3.556%. This study can provide a theoretical reference for the structural design of new drip irrigation emitters and functional analysis of vortices.