灌区自压微灌独立管网系统优化设计研究

微灌管网系统由田间管网系统和骨干管网系统两部分组成,田间管网入口所需压力只与灌水器设计工作水头及田间管网允许水头差有关,因此两部分的优化问题是相互独立的。目前田间管网优化设计主要是在限定面积且布置已定的情况下进行支毛管管径组合优化。本研究在不限定管网系统面积的情况下建立了单向毛管田间管网、双向毛管田间管网及自压微灌骨干管网的优化设计数学模型,可同时完成相应管网的优化布置和优化设计且能得到最佳控制面积。利用解的不可行度对随机产生的初始种群进行选择以改善种群质量,利用罚函数法处理约束条件,应用遗传算法进行优化计算。结果表明:双向毛管田间管网在控制面积及单位面积投资两方面均优于单向毛管田间管网,推荐以双向毛管田间管网优化结果为基础进行骨干管网的优化,算法收敛性能稳定,具有较高的计算精度,此优化设计研究成果对自压微灌系统设计及区域管网优化设计具有一定的实际意义。

Optimal design of the gravity micro-irrigation pipe network for irrigation district

Micro-irrigation pipe network system is composed of field pipe network system and main pipe network system,the pressure at the entrance of field pipe network is only related to emitter operating head and the difference of allowable pressure head of field pipe network, so the optimization of the two parts are mutually independent. Currently, optimal design of field pipe network is mainly in the conditions of ar-ea is limited and layout has been confirmed. In this paper, optimum design mathematical models of field pipe network with unilateral capillary and paired laterals and main pipe network were established in the condition with unlimited area of pipe network, which can optimize both the layout of pipe network and pipe diameter simultaneously,and obtain the best control area of pipe network. In order to improve the pop-ulation quality,an infeasible degree of solution is adopted to select the initial population that generated ran-domly. In the model, the penalty function method is adopted and the genetic algorithm is applied to carry the optimization. The results show that field pipe network with paired laterals is better than that with unilat-eral capillary in control area and investment of unit area, so field pipe network is recommended as the foundation of main pipe network optimization, the algorithm is of good convergence and high precision. The results of this paper have some practical significance for optimal design of the gravity micro-irrigation pipe network and regional pipe network.