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目的:探索高扬程条件下4mm虹吸管内气体集聚现象对虹吸流速的影响,并对传统虹吸流速水力学计算公式进行修正。创新点:1.通过对比物理模型实验值和计算值,得出了高扬程虹吸流速的控制因素及传统虹吸流速计算公式在高扬程条件下的不适用性;2.通过分析实验数据,对有压管流水力学公式进行修正,使之适应高扬程条件下的虹吸流速计算。方法:通过物理模型试验,揭示高扬程虹吸流速的特征(图3);将高扬程虹吸流速实验值和传统虹吸流速水力学公式计算值进行对比(表3和4);通过分析实验数据,结合有压管流水力学公式,得出高扬程虹吸流速经验公式(公式(5)和(8))。结论:1.在高程差H_1一定时,虹吸流速与扬程呈负相关;在扬程H0一定时,虹吸流速随高程差H_1的增大而流速加快,直至达到最大流速,并保持稳定状态;虹吸流速与管长呈负相关。2.高扬程虹吸排水由于管内气压降低析出大量气泡,形成气液二相流,影响虹吸流速的计算;目前采用的有压管流水力学计算公式不适用高扬程4mm虹吸管的虹吸水流。3.当H_1<2ΔH,虹吸流速的控制因素为高程差H_1;当H_1≥2ΔH,虹吸流速的控制因素为当地虹吸极限扬程H_(max)和H_0的差值ΔH;4.对于高扬程4mm虹吸管虹吸流速的确定,一是可以直接实验测定,查找相关数据,二是可以采用经验公式来确定相关的虹吸流速。
Objective: To explore the effect of gas accumulation in 4mm siphon tube on siphon flow velocity under high head condition, and to correct the traditional formula of siphon flow hydrodynamics. Innovative points: 1. By comparing the experimental and calculated values of the physical model, the control factors of high-lift siphon flow velocity and the applicability of the traditional siphon flow velocity formula in high lift conditions are obtained.2. By analyzing the experimental data, Pressure pipe flow mechanics formula to be amended to adapt to high lift conditions siphon flow rate calculation. Methods: Physical model tests revealed the characteristics of high-lift siphon flow rate (Figure 3). The experimental results of high-lift siphon flow rate and traditional siphon flow rate equations were compared (Table 3 and 4). By analyzing the experimental data, There are pressure pipe flow mechanics formula, derived high-lift siphon flow empirical formula (formula (5) and (8)). When the elevation difference H_1 is constant, the siphon flow velocity is negatively correlated with the head; when the head pressure H0 is constant, the siphon flow velocity increases with the elevation difference H_1 and the flow velocity accelerates until the maximum flow velocity is reached and the steady state is maintained. The siphon flow velocity Negative correlation with manager. 2.High-lift siphon drainageA lot of bubbles are precipitated due to the decrease of gas pressure in the pipe to form gas-liquid two-phase flow, which affects the calculation of siphon flow velocity. Currently, there is a pipe siphon formula for high-lift siphon pipe. 3. When H_1 <2ΔH, the control factor of the siphon flow rate is the elevation difference H_1; when H_1≥2ΔH, the control factor of the siphon flow rate is the difference ΔH between the local siphon limit head H_max and H_0; 4. For the high-lift 4mm siphon Siphon flow rate determination, one can be directly determined experiment, find the relevant data, and second, you can use the empirical formula to determine the relevant siphon flow rate.