Optimizing pressurized drip irrigation pipe network design using an improved NSGA-Ⅱ algorithm and engineering depreciation cost method
[Objective]Optimizing pipe networks is a critical aspect of drip irrigation design.This paper proposes a multi-objective method to optimize pressurized drip irrigation network design and evaluate its applicability.[Method]The optimization method incorporates two objectives:minimizing the cost per unit area and improving network reliability by reducing the variance of surplus head at unfavourable nodes in the network.A mathematical model was developed,accounting for depreciation costs and operation and management expenses.The proposed model was applied to a pressurized drip irrigation network in an irrigation area in Xinjiang.The performance of the improved NSGA-Ⅱ(Non-dominated Sorting Genetic Algorithm Ⅱ)was compared with the original algorithm by analysing the Pareto frontier solutions.[Result]The Pareto frontier solution obtained by the improved NSGA-Ⅱ algorithm is better than that obtained by the original algorithm.When the cost of a unit area was the same,the optimal network obtained by the improved NSGA-Ⅱ algorithm was more reliable than that obtained by the original algorithm.Across 50 independent calculations,the uniformity index value of the improved NSGA-Ⅱ and the original algorithm was 0.371 and 0.404,respectively.The cost of a unit area calculated using the improved NSGA-Ⅱ algorithm was 792.92 yuan/hm2,compared to 851.89 yuan/hm2 budgeted in the original project.The optimisation calculated by the proposed method reduced the variance of surplus head at the unfavourable nodes in the network from 0.15 to 0.06.[Conclusion]The improved NSGA-Ⅱ algorithm is more effective than the original algorithm,offering a practical approach to reducing costs and enhancing the reliability of pressurized drip irrigation pipe networks and similar hydraulic systems.