Structure design and hydraulic performance analysis of drip emitters based on vortex energy dissipation

Abstract

AbstractThe centre of the vortex within the drip irrigation emitter easily forms a low‐speed or zero‐velocity zone, which easily causes sediment deposition and blocks the narrow channel of the emitter. To solve this problem, a funnel‐shaped drip irrigation emitter was designed and optimized. Numerical simulations and field tests were conducted to compare and analyse the flow index, energy dissipation coefficient and relative energy dissipation ratio of the emitter. The results showed: (1) When the incident angle (θ) of the diversion channel increased from 0 to 37.4°, the energy dissipation increased from 20% to 64%. The main way of energy dissipation in the emitter changed from impingement of water to viscous drag in the vortex. (2) Under normal pressure, the energy dissipation coefficient of the vortex energy dissipation scheme (F5) was 60% higher than that of the impingement energy dissipation scheme (F1). The flow index of F5 was lower than that of F1 in both the high‐pressure and low‐pressure regions, which was in the range of 0.433–0.466. (3) Due to the spiral flow, there was a vortex with a large axial velocity inside the conical cavity, which can effectively avoid sediment deposition in the vortex centre.