Fuzzy evaluation and performance index of variable-rate sprinklers

The parameters of variable-rate sprinkler changed continuously when it is rotating, and the evaluation index of commonly sprinklers can not reflect the characteristics adequately. To overcome this problem, indexes of rotating time and the sprinkler evaluation index for variable spraying were proposed. The indexes mainly included the wetted radius reduced coefficient, the spraying shape coefficient, the uniformity coefficient, the variations of intensity coefficient and the variations of hit intensity coefficient. The fuzzy mathematics method was adopted, and the fluidic sprinkler typed BPXH20, BPY120 and BPY220 were evaluated with the five evaluation index factors. According to different applications of the sprinklers, the results of evaluation weights value changed by ±20% show that the evaluation weight values of the uniformity coefficient, the variations of intensity coefficient and the variations of hit intensity coefficient were very sensitive but would not impact results of the quality evaluation. It can be concluded that weight values were suitable for evaluating the variable-rate sprinklers in this paper, and the methods may be provided references for other variable-rate sprinklers.