Static simulation on water distribution characteristics of overlap area and whole spraying area for sprinkler

Abstract: This paper focused on water distribution characteristics of single, double and multiple sprinklers of large-scale lateral-moving sprinkler system. An experiment was carried out to measure Nelson R3000 and O3000 single sprinkler water distribution by catch cans. The catch cans were laid in the radiation lines in 8 directions. The spacing of 2 catch cans was 0.5 m along each line. The center point was a set of sprinkler, including a sprinkling system mounted 1.8 m high. A total of 6 pressures (from 50 kPa to 300 kPa) were applied in the process of measurement of a single sprinkler. Measurements included water depth, spraying radius, discharge and running time. The Christiansen uniformity (CU) and distribution uniformity (DU) of sprinklers were calculated. The superposition method with MATLAB was conducted to simulate water distribution of 2 sprinklers and multiple sprinklers by single sprinkler data. Meanwhile, CU, DU and mean spraying intensity (MSI) of 2 sprinklers and multiple sprinklers were obtained in MATLAB. Moreover, the overlap area (OA) and non-overlap area (NOA) were separated according to superposition principle and spraying spacing. The theory was that if one-point MSI was not 0, the point belonged to the whole spraying area. Meanwhile, the distances between the point and 2 of the sprinklers were less than spraying radius, which meant the point was in the OA. Otherwise, this point was in the NOA. The results showed the mean CU and DU of R3000 sprinkler were 68.79% and 50.82%. The CU and DU of R3000 sprinkler increased before the pressure of 150 kPa, indicating that the spraying effect was best at 150 kPa. The mean CU and DU of O3000 sprinkler were 65.33% and 55.69%. The CU and DU of R3000 sprinkler increased before the pressure of 200 kPa, indicating that the spraying effect was best at 200 kPa. The standard deviation of the uniformity showed that the O3000 was more stable than the R3000 at the pressure of 50-300 kPa. The water depth distribution and spraying intensity distribution at 150 kPa away from the sprinkler and showed that the R3000 had the highest water depth at about 2 and 4.5 m away from the sprinkler and the O3000 had the highest water depth at about 5-6.5 m away from the sprinkler. The spraying radius of R3000 and O3000 was 7.5 and 8.0 m, respectively. For the 2 R3000 sprinklers combinations, the CU decreased with the spacing of the 2 sprinklers increased to 4.5 m, the DU was smaller than 60% when the spacing between the 2 sprinklers was 1-5.5 m, and the mean spraying intensity (MSI) decreased with the spacing increased. For the 2 O3000 sprinklers combinations, the CU decreased with the spacing of the 2 sprinklers increased to 6.5 m, the DU was about 54%-60% when the spacing between the 2 sprinklers was 1-8 m, and the MSI decreased with the spacing increased. The overlap area of the 2 sprinklers decreased but the spraying range increased with the spacing increased from 1 to 7 m. For the multiple R3000 sprinklers combinations, the CU increased when the spacing was increased from 1 m to 6 m and the maximum CU was 68% at the spacing of 6 m, and the DU increased when the spacing increased and its value was above 50% at the spacing of 6 m. For the multiple O3000 sprinklers combinations, the CU and DU were highest with 72% and 57%, respectively at the spacing of 7 m, and were lowest with 55% and 31% at the spacing of 1 m.The CU and DU in the overlap area was higher than the whole spraying area but the CU was still lower than 85%. The study provides valuable information for the design of the sprinkler system.