Abstract:

With continuous improvement, drip irrigation technology has gradually been widely used in the field of agricultural planting. The emitter is the core component of the drip irrigation system, and the main reason hindering the development of the emitter is that the structure of the emitter flow path is narrow, which increases the amount of its irrigation time. Simultaneously, blockage occurs. The article reports a study on the flow characteristics and clogging causes of labyrinth channels with different internal tooth structures under different conditions, aiming to find a channel structure with better anti-clogging performance.

This paper uses FLUENT numerical simulation analysis to compare the velocity and turbulent kinetic energy characteristics of three different internal tooth structures (rectangular, triangular and arc) and different internal tooth combinations (single internal teeth, double internal teeth and combined internal teeth), and, combined with the DPM stochastic orbital model, studies the migration under three different pressure conditions (0.06 MPa, 0.11 MPa and 0.15 MPa) and with three different particle sizes (0.05 mm, 0.085 mm and 0.130 mm). The indicators of the hydraulic performance of the emitter are the turbulent kinetic energy of the flow channel, the intensity of the low-turbulent kinetic energy area or low-velocity area in the flow velocity, and the distribution of the dissipation rate of the turbulent kinetic energy of the flow channel; the indicators of the anti-clogging performance of the emitter are based on the fluid-solid. The particle migration path and particle residence time in the flow channel are obtained from the two-phase (DPM stochastic trajectory model) analysis, and the influence of the parameters of the labyrinth flow channel with different internal tooth structures on the performance of the emitter is studied under numerical simulation. Combined with the above analytic conclusions, a labyrinth flow channel with internal teeth is designed with better performance.

The results show that, among different combinations of internal teeth, the combined structure is the best flow channel structure, and the flow channel has the greatest strength in the low turbulent kinetic energy region or low velocity region, indicating that the hydraulic performance of the flow channel is better. However, the migration paths of the large-size particles are fewer, the residence time of the particles in the flow channel is shorter, and the particles are easy to flow out of the flow channel as the water flows so that the flow channel is not easy to be blocked. This study finds that the size of the internal tooth area affects the anti-clogging performance of the internal tooth channel. Combined with the optimal internal tooth combination, the optimal internal tooth structure is triangular (the reference index is consistent with the above-mentioned data). Based on the above research conclusions, it can be seen that the optimal flow channel is a combined triangular internal tooth. On the basis of this research (the reference index is consistent with the above-mentioned data), the improved flow channel not only increases the ability of the fluid to maintain the turbulent state in the flow channel, but also significantly improves the flow velocity and turbulent kinetic energy, making a better particle migration trajectory and better anti-blocking effects.

In conclusion, this study provides valuable insights into the flow characteristics and clogging causes of drippers with different internal tooth structures, and identifies flow channel structures with better clogging resistance. The results of this study may be useful for the design and optimization of dripper structures in irrigation systems.