In order to be able to irrigate all of square area, a preliminary experiment was carried out to study the effect of changing the area cross-section of the water outlet of pop-up sprinkler on pressure and wetted radius.The pre- experiment results were used in the design and manufacture of two models, each of them consists of two parts from artilon materials, which were added to the pop-up sprinkler. A final experiment was carried out to evaluate the performance of the modified pop-up sprinkler (MPS) after adding the two parts to the sprinkler in comparison of the normal pop-up sprinkler (NPS) at the same wetted radius. The parameters under study were two designs of the fixed part {the first design with dimensions of nozzles (2×d) mm where d= (1.2:8.1) mm, the second design with dimensions of nozzles (3×d) mm where d= (4.1:11.8) mm}. The positions of pressure reduce valve were closed and open. The internal nozzles dimensions of the rotor part were {(3×8), (2×8), (1×8)} mm for first design and {(4×11.8), (3×11.8), (2×11.8)} mm for second design. The results showed that,the collected water from MPS by first and second design was found to be greater than which collected from NPS at a distance of 2 and 4 m from the sprinkler. On the contrary, the amount of fallen water from NPS was found to be greater than which collected form MPS at a distance of 6 to 8 m from the sprinkler. The amount of collected water when the valve was closed was larger than one when the valve was opened. In case of the first design, the amount of fallen water near the sprinkler was increased then decreased by increasing the distance from sprinkler. Also, the amount of water fell at the angle of Ɵ= (45, 135, 225, 315) was greater than the amount of fallen water at the angle of Ɵ = (0, 90, 180, 270).
In case of the second design, the amount of fallen water was increased by increasing the distance from sprinkler to reach maximum value at 4 m, then the amount of fallen water was decreased. Also, the amount of fallen water at the angle of Ɵ = (0, 90, 180, 270) was greater than one which fell at the angle of Ɵ = (45, 135, 225, 315). MPS in the first design obtained Christiansen ʼs uniformity coefficient smaller than that obtained by NPS. On the contrary, MPS in the second design obtained Christiansen ʼs uniformity coefficient greater than which obtained by NPS. MPS in the first and the second design obtained distribution uniformity (DU) smaller than which obtained by NPS. MPS with the first design gave application efficiency of low quarter smaller than which obtained by NPS. MPS with the second design gave application efficiency of low quarter greater than which obtained by NPS at the same wetted radius. The smallest results of coefficient of variation for square shape (C.VS) recorded 15.3% by MPS with the second design and internal nozzle dimension was (4×11.8) mm using closed valve position.