DEM Study of Clogging in Millimeter Scale Channels in Drip Irrigation Emitters*

This work uses discrete element modeling (DEM) to evaluate the magnitude and frequency of emitter clogging in millimeter scale channels in drip emitters, and presents novel path designs that reduce the likelihood of clogging.  Preventing and mitigating clogging in drip irrigation systems can require time-intensive and costly efforts.  Studies have shown that clogging in typical labyrinth channels is most likely to occur in regions of low speed recirculating flow. These recirculation zones can be desirable in low flow rate emitters, as they create a larger pressure drop within a given cross-sectional area.

Experimental data was used to assess the accuracy of a DEM model with three commercial path designs.  Modeling and experimental results were used to define and evaluate a dimensionless time variable to compare the clogging likelihood among paths with different output flow rates.  The flow trajectories predicted by the computational model in each path were used to analyze which flow characteristics increased the likelihood of clogging.  Insights on clogging in conventional labyrinth channels were used to design drastically different flow paths with minimal low velocity regions, while maintaining the desired pressure drop.