Investigating the Effect of Water Volume Control Emitters on Water Distribution Uniformity of the Micro-irrigation System

The performance of the existence emitters in micro-irrigation systems is on the basis of pressure dissipation and the inefficiencies of these systems in the pressure and discharge uniformity regulations have been reported by researchers. In this research, in order to improve emitters' efficiency in micro-irrigation systems, a new emitter named water volume control emitters was designed and evaluated. One hundred emitters were installed in the field condition on a micro-irrigation system and the applied water volume was measured until cutoff time. The experiments in pressures of 0.5, 1, 1.5, 2 and 2.5bar with three repetitions were conducted. In each repetition, the cutoff time of the emitter located in five positions at the first, third, mid, two-thirds and end parts of the lateral pipe were measured. Finally, the obtained results were evaluated on the basis of ASAE standards. In the field experiments, the maximum value of variation coefficient was obtained 3.3% in the pressure of 0.5bar (minimum pressure). Therefore, the system performance was evaluated in the excellent category in the all applied pressures. Also, the minimum coefficients of distribution uniformity (97.6%) and emission uniformity (91%) were obtained in the minimum pressure of 0.5bar so that these values were very favorable. In all of the pressure-discharge equations, the discharge exponent values were approximately estimated 0.55. The type of flow in emitters was turbulent. The appropriate performance of the mentioned emitters in creating a favorable water distribution uniformity showed that the change of view about emitters' operational mechanism and the developing new emitters with efficient mechanism can improve the efficiency of micro irrigation systems.