Simulation study on the influence of trickle laterals equipped with integrated in-line and out-line emitters on the hydraulic characteristics

Objective  To study the influence of emitter mosaic mode on the hydraulic characteristics of trickle laterals.

Method  Two kinds of trickle laterals equipped with integrated in-line emitters and one trickle lateral equipped with integrated out-line emitters were tested. At the same time, three kinds of trickle laterals were simulated and verified by computational fluid dynamics (CFD) method. On this basis, the head loss and laying length of trickle laterals equipped with integrated in-line and out-line emitters under different discharge were simulated and calculated.

Result  The simulated values of the total head loss of trickle laterals equipped with integrated in-line and out-line emitters were slightly lower than the measured values, and the relative deviation between the simulated and measured values of trickle laterals equipped with integrated out-line emitters was smaller. The drip head embedding mode had a significant influence on the hydraulic characteristics of trickle laterals. Compared with trickle laterals equipped with integrated in-line emitters, the total head loss of trickle laterals equipped with integrated out-line emitters was smaller, with the reduction ratio of the total head loss exceeding 49.2%, and the reduction ratio of the total head loss gradually increased with the increase of the drip head flow. The maximum laying length of trickle laterals equipped with integrated out-line emitters was longer than that of trickle laterals equipped with integrated in-line emitters, and the length increased by 21.6% to 56.9%. The main reason for the greater total head loss of trickle laterals equipped with integrated in-line emitters was that the pressure gradient of trickle laterals equipped with integrated in-line emitters consumes a large amount of water flow energy due to the redistribution of the flow velocity in the section.

Conclusion  The hydraulic performance of trickle laterals equipped with integrated out-line emitters is better than that of trickle laterals equipped with integrated in-line emitters. For the design of long distance economic crop drip irrigation system, trickle laterals equipped with integrated out-line emitters can be given priority.