【作者】 付玉娟；

【导师】 蔡焕杰；

【作者基本信息】 西北农林科技大学 ， 农业水土工程， 2008， 博士

【摘要】 管道输、配水灌溉系统与其它节水灌溉技术相比在提高灌溉水利用率、节省农田、便于机耕和扩大灌溉面积等方面都显示了巨大的效益和潜力。管道化灌溉将是本世纪节水灌溉发展的一个重要趋势,但与此相应的是管道系统建设规划设计内容复杂,需要的材料和设备多,一次性投资较高。因此进行灌溉管网优化设计,即寻求满足水量、水压、流速等约束条件,使管网投资、年运行费或单位面积上的投资最小,系统可靠性高的设计方案,对节约投资、降低能耗、促进新技术的发展都有重要的现实意义。本文以灌溉输、配水管网的优化为研究对象,借鉴前人研究成果,采用现代数学优化方法,对各类管网的优化设计模型进行研究,取得了以下几个方面的进展:1)建立了树状管网优化布置的数学模型,该模型的目标函数仅有各个管段的长度和流量,既考虑了流量的变化,又摒除了管材的价格、规格型号等因素的影响,使优化计算更直接、简便。在建立模型和求解的过程中,把图论理论和列队竞争算法应用到其中,通过实例验证表明所建立的树状优化布置模型可行,编码方式合理,需要输入的数据少,计算简单,能得到管网优化布置的最优解。2)以往的管网优化模型都是以管材费用或者经过折算的管材费用最小为目标建立优化模型的,它忽略了其它费用项对对优化结果的影响,只能达到使管材费用最小的目标,并不能达到管网系统整体投资费用的最小的目的。在树状重力输、配水管网中,提出了以两种重力水头利用率,即管段水头利用率和路径水头利用率最大为目标建立优化设计模型,既达到管材费用较小,又充分利用地形落差所产生的重力水头,减少消能减压设施的费用,真正达到使系统总投资最小的目标。用列队竞争算法对该模型进行求解,通过实例验证表明用该方法适用于树状重力输、配水管网的优化设计,且当项目所在地的地形落差较大时,优化效果更显著。该方法收敛速度快,而以路径重力水头利用率为目标函数的模型因没有约束条件的限制,计算速度更快。3)现有的管网规划模型大都是确定性规划模型,但在系统的使用年限内,各用水单位的需水量、灌水方法、管道输水能力都是变化的,即有一些设计参数在设计年限内是变化的。本文将管段设计流量、管道粗糙系数、节点工作水头作为随机变量,建立了基于约束规划的树状管网不确定优化模型。通过算例分析表明,不确定优化模型与确定性优化模型所得的优化结果中,如管段设计流量、管径组合方案以及管材费用等都有显著的不同,且该模型与实际情况更接近。在实际的规划设计当中,需要对工程进行实地的考察分析来确定不确定规划的有关参数,如随机变量的方差、置信水平等。4)环状管网由于节点压力分布均匀,水量调度灵活,管道利用率高而得到了广泛的应用,但目前对环状管网优化设计的研究则比较少。环状管网优化优化计算的核心是管网的水力平衡计算,其目的是在确定管径的情况下求出满足连续方程和能量方程的节点压力水头和管段设计流量。本文用列队竞争算法产生管段组合方案并进行优化计算,用基于图论理论的水力平衡计算模型计算出满足连续方程和能量方程的各节点压力水头、所需扬程和管段设计流量等,该模型把复杂的水力计算转化为向量、矩阵运算,且无需进行初始流量分配。5)目前制约灌溉管网优化设计发展的其中一个原因是管网的规划设计没有与考虑将它和实际地形相结合,而它本身又受地形的影响与制约,所以在一定程度上管网的优化研究还停留的在理论研究上。本文将地理信息系统以及数据库技术应用到管网的优化当中,用地理信息系统的空间分析和网络分析功能和数据库的大量数据存储、计算处理能力,实现了地图、优化计算模型和管网数据的存储、读取的无缝连接,将优化计算结果可视化显示出来,用起来更方便直观。6)所建立的模型都是以实际应用为最终目标的。本文在所建立的模型的基础上,用Visual Basic编程语言、MapX组件和Access数据库开发了灌溉输、配水管网优化软件。并通过工程实例对所建立的模型和程序进行了验证和测试。更多还原

【Abstract】 Compared with other water-saving irrigation technology, delivery and distribution pipe network systems have great superiority and developmental potential in improving the utilization of irrigation water, saving farmland, expanding irrigated area and tractor-plowing. Pipeline networks will be an important trend for water-saving irrigation in the development of irrigation. Meanwhile, pipeline network systems are complex to design, need much more materials and equipment; its first-time investment is much higher. Seeking the optimum plan of pipe network with the higher irrigation quality, less investment and lower consumption of energy can produce great economy benefits using the optimal design theory, methods and tools.This paper takes irrigation pipe network optimization as research object, based on the summarization of the domestic and foreign pipe network optimization and the optimized technology achievement, using modern mathematics optimization method, discussed several type of pipe network. The mainly research achievements of this paper are as flowers:1) Build the optimal layout model for tree pipe network. The objective function of this model only has parameters of pipe length and flow, not only take flow change into consideration but also exclude the influence from pipe price, pipe type, etc, that get the optimal calculation directly and easy. Use the graph theory and LCA (Line-up Competition Algorithm) in the process of modeling and computer, LCA with the f two means competition that between families and inside a family and little controls parameter was introduced in optimal design. It was testified by case study that this model can obtain the optimal result, and is better in search efficiency and stability compared with other algorithm.2) Previous irrigation pipe network model take pipe cost as objective function in pipe network optimization which ignored the other fee for network build and run, can’t guarantee that the optimal design calculated by that objective function can provides a satisfactory performance practically. This paper proposed take the utilization degree of gravity head to evaluate the design’s utilization rate of pressure drop created by hypsography, using two different expressions namely utilization rate of pipe gravity head and utilization rate of path gravity head as network optimization objective functions. The result testified by case study and compared with the model based on minimization of cost showed that the method this paper proposed is more suitable for tree pipe network with more elevation difference and can obtain the optimal result and is superior in search efficiency.3) The existed water distribution pipe net work deterministic optimal design model simplified the influence factor for model development, but many parameters is uncertain in practical, the existed model doesn’t consider the influence on optimal result of uncertain parameter. This paper took pipe flow, node required minimal water head and pipe roughness coefficient as stochastic, established pipe network chance-constrained programming models for optimal design of water distribution network by gravity pressure and pump station. Based on the technical of stochastic simulation, line-up competition algorithm was applied for model solving. The result testified by case study showed that the uncertain parameter had obvious influence to optimal result, and with the wider variable range, the larger pump and cost.4) For evenly pressure distribution, flexible flow dispatch and high rate of pipe utilization, the loop network is widely used, but the research about it is less. The core of loop pipe network optimization is hydraulic balance calculate, to get pipe pressure, flow, pump head etc. This paper use LCA to optimal calculation, and graph theory to hydraulic balance calculation, make the complicated hydraulic calculation become simple matrix transform, needn’t initial flow distribution.5) One of the main factors that restrict the development of pipe network optimization is that the optimal design isn’t take the terrain into account. In some extent, the pipe network optimal is still remains at theoretical research. This paper takes GIS and Access Database into irrigation pipe network optimization, uses spatial analysis and network analysis function of GIS, data store and data processing function of database, achieve seamless link of map, optimal model and data’s read-write and store, the result can be showed by three approach, such as map, program and database.6) All optimal models build are for practical application. The program using Visual Basic language, MapX COM (Component Object Model) and Access database have been designed for irrigation delivery and distribution pipe network optimization. The models and the program tested by case study showed that the program have great practicality and universality.更多还原