Study On The Influencing Factors Of Irrigation Uniformity And Flow Rate Decline Of Inlay Patch Drip Irrigation Belt

As the last equipment of drip irrigation system,its hydraulic performance and physical plugging performance will directly affect the operation efficiency of the whole system.In this paper,the inlay patch drip irrigation belt was taken as the research object,irrigation uniformity and flow rate decline were taken as evaluation indexes.We designed uniform orthogonal test scheme to carry out physical laboratory test under clear and muddy water conditions.Statistical product and service solution(SPSS)and projection pursuit regression(PPR)were used to process the test data so that we can explore the influence of different factors on hydraulic performance and physical plugging performance of drip irrigation belt.The research results will not only provide a reference for the prediction of irrigation uniformity and flow decline in the drip irrigation belt,but also play a certain reference role in the construction of the theoretical system of drip irrigation system design and operation.The main research results are as follows:(1)Under the condition of clear water drip irrigation,there is no significant effect on the test results of irrigation uniformity of drip irrigation belt by using these two different methods(loop method and closed circuit method).(2)Under the condition of clear water drip irrigation,the effect of working pressure and laying length on irrigation uniformity is significant,and the effect of laying slope on irrigation uniformity is not significant The order of three factors on irrigation uniformity is as follows:working pressure>laying length>laying slope.Under the condition of clear water,the PPR prediction model with the above three factors and irrigation uniformity was constructed.The relative error between the predicted value and the measured value was less than 0.55%,and the standardized root mean square error of the model was 0.33%,showing excellent performance.(3)The results show the sediment concentration is the main factor affecting the irrigation uniformity and flow rate reduction of drip irrigation belt,and the effect is extremely significant;the influence of working pressure on the irrigation uniformity and flow rate reduction is significant.The effect of laying slope on irrigation uniformity is significant,but not on the flow rate reduction.The order of the influencing factors on irrigation uniformity is:sediment concentration>laying slope>working pressure;the order of influence on discharge drop is sediment concentration>working pressure>laying slope.(4)A PPR prediction model was established to test the sediment concentration,laying slope,working pressure and irrigation uniformity and flow rate reduction under muddy water condition.The relative errors between predicted and measured values were less than 9.07%and 5.31%.The standardized root mean square error of the two models were 2.98%and 2.42%.Through the PPR optimization simulation calculation,under the condition that the irrigation uniformity is the best,the factor level of the optimal condition of irrigation uniformity and flow rate reduction is obtained as follows:the laying slope is 0%,the sediment concentration is lg/L,and the working pressure is 96kPa.The irrigation uniformity is 0.9585 and the flow reduction is 8.35%under this condition.