圆形管渠直角分支口处水力特征试验研究  

Experimental Study on Hydraulic Characteristics at Right-angled Branch of Circular Channel

作　　者：王旭庆 王文娥[1] 皮滢滢 王亚菲 胡笑涛[1] WANG Xu-qing;WANG Wen-e;PI Ying-ying;WANG Ya-fei;Hu Xiao-tao(Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas,Ministry of Education,Northwest A&F University,Yangling 712100,Shaanxi Province,China)

机构地区：[1]西北农林科技大学农业水土工程教育部重点实验室,陕西杨凌712100

出　　处：《中国农村水利水电》2024年第6期75-81,共7页China Rural Water and Hydropower

基　　金：国家自然科学基金联合基金重点项目(U2243235)。

摘　　要：管网分水是管网运行的重要模式,为探索圆形管渠直角分水口附近处的基本水流特征,采用DN315的PVC圆管,在5种流量、5种分流比条件下开展管渠直角分水口过流试验,测量了分水口处局部水深,采用多普勒声学流速仪(ADV)测量了典型断面上的三维瞬时流速,分析了管渠直角分水口典型断面的时均流速分布及水头损失。研究表明:分水口附近主管水面线大体呈现先减小后增加的趋势,大流量下水面线壅高程度高,分流比对口门处水面线影响较大。纵向流速经过分水口流速降低,而横向流速增加。分水口上下游纵向和横向流速呈对称分布,而在分水口区域靠近分水口侧数值较大。纵向流速垂向呈现抛物线型分布,分水口中轴断面处出现负值即存在回流区;横向流速垂向呈内凹型分布,不存在负值即不存在横向环流。水平流场的分流宽度随分流比的增大而增大,断面中层分流宽度大于其他层。水头损失系数在流向支管向远大于流向主管向,在分流比为0.4、流量为50 L/s总水头损失系数最小。本研究对于指导管网设计及运行具有重要意义。Water distribution is an important mode of the pipe network operation.In order to explore the basic water hydraulic characteristics near the right-angled branch of the circular channel,DN315 PVC round pipes were used to carry out tests under 5 flow rates(30,35,40,45,and 50 L/s)and 5 split ratios(0.1,0.2,0.3,0.4,and 0.5)in this paper.Measurements of the water depth and three-dimensional instantaneous velocity on typical sections were recorded,using the Acoustic Doppler Velocimeter(ADV),and the mean velocity distribution and the head loss near the unpressurized pipe branch were performed.The research shows that:the surface line of the main pipe near the right-angled branch generally decreased first and then increased.High plugged water level of the large flow(45 L/s)requires attention to the headroom.The split ratio mainly affected the water level in the mouth part.The longitudinal flow velocity through the branch decreased,while the transverse flow velocity through the branch increased.The vertical and transverse flow velocity of the upper and lower the branch were distributed symmetrically,and the velocity near the right-angled branch side was larger in the area of the bleeder.The longitudinal velocity was distributed in a parabolic vertical direction,and the longitudinal velocity appeared negative at the middle axial section of the bleeder,that is,there was a reflux phenomenon.There was no negative velocity of the transverse velocity,that is,there was no lateral circulation,and the transverse velocity was distributed in a concave vertical direction.The diverter widths of horizontal flow field increased with the increase of the split ratios,and the diverter widths of middle section were larger than that of other layers.Head losses were different under different flow rates and spilt ratios,and the coefficient of total head loss was the smallest when the diversion ratio was 0.4 and the flow rate was 50 L/s.This study is of great significance to guide the design and operation of pipe networks.

关 键 词：圆形管渠 直角分水口 水面线 流速分布 水头损失 

分 类 号：TV131.29[水利工程—水力学及河流动力学]