虹吸式雨水排水系统单斗排水性能研究

发布时间：2018-07-26 15:33

【摘要】：随着城市建设的快速发展,大空间、大容量、大跨度的建筑数量持续增加,传统的重力排水由于排水量较小、排水管道较多、悬吊管需要设置坡度等原因,已不能完全满足现代大型建筑屋面排水的需求,许多工程开始采用排水性能更加优良的虹吸雨水排水系统,但现有虹吸排水系统的设计校核方法是基于满管流状态进行的,对于虹吸的启动和形成过程了解还不够深入。而且现有系统中悬吊管长度均是依据屋面结构进行设计,没有考虑到对虹吸排水性能的影响,规范中也没有针对悬吊管长度的相关限制。本文主要针对虹吸形成过程的系统参数动态变化规律以及管道系统中悬吊管长度的校核方法进行研究。论文首先对虹吸排水系统进行理论分析,总结虹吸排水系统的形成条件和判断标准,提出虹吸排水的性能指标;搭建单斗虹吸排水系统实验台,采用间接测量法研究不同补水量条件下系统参数的动态变化规律,根据补水量(大流量工况:Q80%,中流量工况:55%Q80%,小流量工况:30%Q55%)把流态及管道参数变化分为三个类型,并应用文献测试数据进行验证。其次,采用STAR-CCM+软件,VOF方法建立虹吸排水系统数值计算模型,对大流量工况下的虹吸形成过程进行模拟,通过对管内流态变化过程、系统参数曲线变化趋势、虹吸启动时间、最大排水量与实验结果的对比,证明了数值计算方法的准确性和可行性;同时,选取管道结构参数对虹吸启动时间进行了影响因素敏感性分析,结果表明:悬吊管长度、立管直径、悬吊管管径、尾管长度4个因素对虹吸启动时间影响较大,提出了应用上游管道体积来简化计算虹吸启动时间的思路。最后,针对现有虹吸排水系统悬吊管较长的问题,提出了悬吊管长度校核方法。该方法基于伯努利方程、连续性方程等理论计算方法以及数值计算结果修正得到悬吊管长度与最大排水量(Q-L2)、悬吊管长度与虹吸启动时间(T1-L2)的简化计算模型,把这两个结论作为悬吊管长度的限制条件,再根据当地的气象条件、屋面结构、天沟尺寸等参数进一步综合得到悬吊管的最大长度L2,为工程设计提供参考。
[Abstract]:With the rapid development of urban construction, the number of large space, large capacity and large span buildings continues to increase. Many projects have started to adopt siphon Rain Water drainage system with better drainage performance, but the design and checking method of existing siphon drainage system is based on the condition of full pipe flow. The process of siphon initiation and formation is not well understood. The length of suspension pipe in the existing system is designed according to the roof structure without considering the influence on the siphon drainage performance and there is no restriction on the length of the suspension pipe in the code. In this paper, the dynamic variation of system parameters in siphon forming process and the method of checking the length of suspended pipe in pipeline system are studied. Firstly, the paper analyzes the siphon drainage system theoretically, summarizes the forming conditions and judgment criteria of the siphon drainage system, puts forward the performance index of siphon drainage system, builds a single bucket siphon drainage system experimental platform, The dynamic variation of system parameters under different recharge conditions is studied by indirect measurement method. According to the quantity of water supply (large flow condition: Q 80, middle flow condition: 55 Q 80, small flow condition: 30 Q 55%), the variation of flow state and pipeline parameters is divided into three types. And use the literature test data to verify. Secondly, a numerical model of siphon drainage system is established by using STAR-CCM software. The siphon forming process is simulated under the condition of large flow rate. The variation process of flow state in pipe, the change trend of system parameter curve, and the siphon start-up time are analyzed. The comparison between the maximum displacement and the experimental results proves the accuracy and feasibility of the numerical method, and the sensitivity analysis of the influence factors on the siphon start-up time by selecting the structural parameters of the pipe shows that: the length of the suspended pipe, Four factors, such as riser diameter, suspended pipe diameter and tail tube length, have great influence on the siphon start-up time. This paper puts forward a way to simplify the calculation of siphon start-up time by using upstream pipe volume. Finally, aiming at the problem of long suspension pipe in existing siphon drainage system, a method for checking the length of suspension pipe is put forward. Based on Bernoulli equation, continuity equation and numerical results, the simplified calculation models of suspension pipe length and maximum displacement (Q-L2), suspension pipe length and siphon start-up time (T1-L2) are obtained. These two conclusions are taken as the limiting conditions of the length of the suspended pipe, and the maximum length of the suspended pipe L _ 2 is further synthesized according to the local meteorological conditions, roof structure and gutter size, which provides a reference for the engineering design.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU823

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