Numerical investigation of the clogging mechanism in labyrinth channel of the emitter

Emitter clogging is a main factor affecting the performance of drip irrigation products. Considering the small size and intricacy of emitters, numerical methods are introduced to study the clogging mechanism of labyrinth channel in the emitter. A three-dimensional numerical model of clogging analysis is addressed, where Reynolds stress model with wall function is used to simulate the fluid flow in the Eulerian frame, and stochastic trajectory model is adopted to track the motion of the particles in a Lagrangian co-ordinate system without taking into account the agglomerating behaviour of particles. The analytical results show that in the labyrinth channel, low-velocity region is developed ahead of each sawtooth and large vortex is shaped just behind it. Small particles are apt to deposit in those regions due to their better following behaviours than those of large ones. The potential clogging regions predicted by simulation are reasonably consistent with the experimental results. Further, it is also found that the particles ranging from 30 to 50 m behave best when passing through the labyrinth channel, and particle densities have a remarkable effect on the penetration only when their diameters are large than 50 m. Copyright q 2006 John Wiley & Sons, Ltd.