【作者】 许国锋；

【导师】 杨敏；

【作者基本信息】 天津大学 ， 水利水电工程， 2006， 硕士

【摘要】 南水北调中线工程天津干线西起河北省徐水县西黑山进口闸,东至天津市外环河,全长155.419km,采用全箱涵(无压接有压)全自流输水方案,无压段采用2孔无压箱涵输水,有压段采用分段低压输水方式输水。天津输水干线主要控制性建筑物有:进口闸、陡坡段消力池、调节池、保水堰、分流井等,其中保水堰是新型的衔接性水工建筑物,它用于分段低压输水系统中,可自动调整有压段水位分布,保证输水管道中始终处于有压状态。本文基于水工模型和数值模拟,对保水堰的流态、局部阻力系数等水力特性进行了系统的研究,并对其体型进行了初步优化,填补了保水堰研究的空白。主要研究内容包括以下几个方面:(1)通过模型试验和数值模拟对保水堰的局部损失系数和流量系数进行了系统的研究,得到了局部损失系数与水深、堰高、溢流堰相对位置、堰前后高程差、保水堰尺度、不同运行孔数等的关系,保水堰流量系数与堰上水头的关系,完善了分段低压输水系统的设计。(2)通过数值模拟对保水堰堰后挖深、与下游管道衔接的削角、堰后距离、堰前距离等局部体型进行了优化,调整了保水堰过堰水流流态和流速分布,使其体型更加符合水流运行条件,优化结果可供保水堰设计工作者参考。(3)保水堰在不同水深情况下存在三种流态,即淹没堰流、自由堰流和过渡堰流,通过对保水堰流态特性的研究,详细描述了保水堰在不同流态情况下的过流特性。(4)通过模型试验对南水北调工程天津段控制性建筑物:进口闸、消力池、调节池、分流井等进行了水力特性研究,得出了相关的水力参数和流态特性,为南水北调天津干线的设计提供了可靠的数据。更多还原

【Abstract】 In the middle line of the Project of Transferring Water from South to North in China, the Tianjin section lies from Xiheishan inlet sluice in Xushui County in Hebei, and to the Waihuan River in Tianjin. It is 155.419km long. The Tianjin section transfers water in the way of the free flow following pressure flow. The section of free flow delivers water by the two“U”canals. The section of pressure flow transports water in the means of the stepped low pressure pipes. The main controlled hydraulic structures are the inlet sluice, the stilling pool, the regulating pond, water conservation weir, diversion basin and so on. Water conservation weir is the new-style hydraulic structure that can link the pressure conduits. In the general way, the water conservation weir can be used in the stepped low pressure pipes water conveyance system. It can adjust water level distribution automatically in the pressure pipe. And it can guarantee that the pressure pipe is under pressure all the time. Based on the hydraulic model and numerical simulation, the local head loss coefficient and discharge coefficient are systematically analyzed and the local body type is initially optimized. The achievements fill in the blank of water conservation weir.The main researches made by this paper include several aspects as followings: 1. The local head loss coefficient and the discharge coefficient of the water conservation weir are studied on systematically by the combination of physical model and mathematical model. The influencing factor of the local head loss coefficient variation include water level, height of weir, relative position of weir, difference of elevation between fore and after of the weir, the dimension of water conservation weir,the operating holes and so on. The relation curve of the local head loss coefficient and influencing factors are obtained. The relation curve of the discharge coefficient and weir head has been also gotten in this paper. The work has been done to perfect the stepped low pressure water convey system.2. The local body type of water conservation weir, such as ditching depth behind the weir, top rake at the inlet of downstream pressure pipe and the length fore and after the weir, is optimized by the way of numerical simulation. Through the optimization, the flow pattern over the weir and the velocity distribution in the pipes downstream are adjusted better. The body type after optimization can accord with the flow pattern. The results can be the reference for the designers of water conservation weir.更多还原