【作者】 郑政；

【导师】 练继建；

【作者基本信息】 天津大学 ， 水利水电工程， 2006， 硕士

【摘要】 多孔并联分段低压输水系统可以简化输水控制条件、保证适时适量输水、降低管道的承压、节省工程造价和运行管理费用;但由于整个输水线路长,当输水系统进行流量调节、关闸检修以及运行孔数转换等操作时,其水力特性和控制问题更为复杂,目前尚未见到相关的研究成果。为此,本文以南水北调工程天津干线为研究背景,对多孔并联分段低压输水系统的水力特性和控制问题进行深入系统地研究,主要研究内容如下:首先,本文通过模型试验测定了多孔并联分段低压输水系统中的调节池、保水堰和分流井等三个重要的新型局部输水建筑物的水力参数;随后建立了这种输水系统的数学模型,着重分析了上述三种比较复杂的新型边界;最后,对南水北调工程天津干线的各种运行工况进行水力数值计算,结合计算结果从以下几方面对多孔并联分段低压输水系统的水力特性和控制问题进行分析:1.探讨了调节池位置、尺寸的变化对多孔并联分段低压输水系统水力特性的影响。2.从检修闸门数量、关闸控制程序和水力学条件等方面综合考虑了有压段并联孔间的连通性影响。3.研究了多孔并联分段低压输水系统在检修工况下的水力特性,针对可能出现的不利现象提出了相应的水力控制措施。4.从改变首闸调节规律、尾部泵站前池抽水量变化的控制变量和计算糙率等三个方面研究了多孔并联分段低压输水系统在流量调节工况下的水力特性。5.推导了多孔并联分段低压输水单元的水流振荡方程和连通式保水堰自由水面的固有振荡频率公式;提出了消除水力共振现象和缓解水力振荡的水力控制措施。以上研究结果可以为南水北调工程天津干线当前的设计和将来的运行管理提供技术依据,有较广泛的推广应用价值。更多还原

【Abstract】 The multiple-hole stepped low-pressurized water diversion system can simplify the condition of water diversion control, assure water diversion timely and properly, reduce the pressure of pipeline, economize the cost of construction and management. However, the length of system is so long that its hydraulic characteristics and control are more complex in the condition of discharge changing, gate closing and holes transition. Meanwhile there is few research about this problem in the past. Therefore, on the grounds of the Tianjin main line of South-to-North water transfer project, this paper systematically does the following researches:First of all, it gets the hydraulic coefficients of three local hydraulic structures, i.e. regulating pond, water conservation weir and water diversion well from model experiment. And then it establishes the mathematical model of the system and detailedly analyzes three boundaries of above structures. Finally it computes the hydraulic transients about the water diversion system of the Tianjin main line of South-to-North water transfer project. Based on the results, it analyzes the hydraulic characteristics and control on the system:1.Discussing the influence on hydraulic characteristics of the system by changing the position and size of regulating pond.2.Synthetically comparing the impact of connectivity between multiple holes by the number of inspection gates, the process of closing gates and the hydraulic control.3.Investigating the hydraulic characteristics in inspection condition and putting forward some hydraulic control measures to avoid the disadvantageous hydraulic phenomenon.4.Investigating the hydraulic characteristics through discharge changing by altering the regulation of the front gate, changing the control variable of pump water in the end and using different roughness.5.Deducing the hydraulic oscillation equation of the multiple-hole stepped更多还原