中文摘要：

给排水管网运行状态的好坏直接影响到供水的压力和水量，影响到服务质量。因此，给排水管网在给排水系统中占据着重要的位置。在管网管道铺设和维修的施工过程中，由于受到地理环境和施工材料的影响，弯管现场制作是不可避免的。目前，弯管制作主要依赖于作业人员的施工经验，由于现场尺寸测量缺乏有效的测量手段，误差很大。同时，对于复杂的施工现场，在大口径弯管的量算和制作存在较大的难度，影响到灌溉管网的施工进程。提出使用测距仪和全站仪，在施工现场进行数据测量的方法，达到快速、方便、准确地测量到对接管道的空间数据。然后，根据现场测量的数据，确定了对接管道中大口径弯管的连接方案和设计方案。最后采用计算流体力学数值方法，分析了弯管结构和参数对弯管内流场和水力损失的影响，为弯管参数的设计优化提供依据。

英文摘要：

The performance of water supply and drainage networks influences the pressure and flow rate of water directly, which is related to service quality. Therefore, the water supply and drainage network is essential for the water system. During pipeline laying and maintenance of the water supply and drainage network, elbow making on site is inevitable because of the impact of the geograph- ical environment or the limit of the materials. For the shortage of effective measurement methods for some special parameters, elbow making is mostly dependent on the experience of the workers and always results in big errors. Besides, in complicated sites, there are great difficulties in the making of elbows with big diameter, which delay the construction of the total pipe network. In this paper, both Rangefinder and Total Station were used for site measurement for achieving correct spatial data of the pipes to be connected in a fast and convenient way in the construction site. Based on the measured data, three connecting ways and the design for the elbow with big diameter were put forward. Finally, computational fluid dynamics was used to visualize the flow field in the elbow and to analyze the effect of parameters on hydraulic performance for parameter optimization.