Abstract:Irrigation system with center-pivot sprinkling system is considered as a system with the highest degree of automation so far. The uniformity in field is one of the important indicators to characterize performance of the center-pivot irrigation system. The off-design working condition was a common phenomenon in actual operation management. Taking Herman-Hein uniformity coefficient ( C UH ) and distribution uniformity coefficient ( D U ) as the evaluation indicators, the influence of off-design working conditions and configuration on uniformity was analyzed by field test. The results showed that C UH was reduced by 12.91%, D U was reduced by 6.35% with low pressure sprinkler D3000, and C UH was reduced by 10.50%, D U was reduced by 2.39% with low pressure sprinkler R3000 when moving speed was changed from 30% to 100%. When the inlet pressure of the center-pivot irrigation system was reduced from designed value of 0.16 MPa to 0.08 MPa, C UH was reduced by 14.04%, D U was reduced by 15.09% with D3000, and C UH was reduced by 13.37%, D U was reduced by 15.61% with R3000. When the end water spray gun was open, C UH was 〖JP〗reduced by 10.27%, D U was reduced by 14.13% with D3000, and C UH was reduced by 20.78%, D U was reduced by 23.15% with R3000. Without pressure regulator under the condition of flat ground, when inlet pressures were 0.12, 0.16, 0.20 MPa , C UH values of the center-pivot irrigation system with D3000 were reduced by 1.23%, 1.82% and 6.51%, D U values were reduced by 29.61%, 14.87% and 12.52%, and C UH values were reduced by 9.26%, 15.00% and 17.19%, D U values were reduced by 40.05%, 32.45% and 29.76% with R3000, respectively.
