Research On Hydraulic Characteristics Of Sewer Based On State Of Serpentine Fluctuation

The urban drains continuous ups and downs, formation of serpentine defects. The drainage pipes snake-like ups and downs of the state affect the drainage normal function. and the internal water flow and will cause urban water logging is a great concern of the administrative department of urban drainage channels.The internal folw in serpentine of drainage.pipes is a complexturbulent flow, due to the presence of ups and downs,there are upstream back water and down stream or water in the pipieline.and there a a greater change of the flow velocity and pressure in the bottom of the pipe. How the snake-like defects affect the normal function of the drainage channels,to evaluate its impact is one of the issues to be addressed in the assessment of the drains. This area have not been reported,this is the first tiome to carry out experimental and numerical analysis of the hydraulic characteristics of the serpentine drains.Based on the classical theory of hydraulics, combined with the existing national standards and pipeline characteristics, this paper design and completion of the experimental setup of a set of drains. According to the experimental needs, the device can change the slope of the pipelineand the ups and downs of the height and position of the segment, while the use of ahomemade water level measurement system on the depth of the serpentine drains a large area,high-density measurements.By the serpentine drains experiment,the state of water-filled experience:anhydrous-overflow-backwater, hydraulic jump-bubble flow, air mass flow-full flow. When the serpentine drains flow is slow flow, a type aⅠ backwater curve in upstream; a type cⅠ precipitation curve in downstream. When the serpentine drains flow is torrent flow, a type aⅡ backwater curve in upstream; a type cⅡ precipitation curve in downstream. The middle of serpentine segment has dramatic flow turbulence will occur the phenomenon of air entrainment. The serpentine of the drains flow capacity by the ups and downs of high-impact is obvious, and has no capacity by the number of the ups and downs. The larger bottom slope and leight of the ups and downs, has great structural impact in the water pipeline.This paper based on the hydraulic phenomena and data, use large-scale commercial software Fluent to turbulent flow simulation in the serpentine drains. In the numerical simulation in the free surface simulation,using VOF two-phase flow model, RNG k-ε turbulence model, the finite volume method to discretize. In the simulation,it Simulated the drainage water filling process, water level speed and vertical speed, the distribution of the pressure in the bottom pipes. Simulation and experimental results are good anastomosis, explain to VOF model can be very good simulation snake-likes ups and downs of the drain pipe flow situation, at the same time, the test and simulation process can be for other defect drainage pipeline to provide reference for the research.