Numerical Simulation Of Non-throat Flume On Trapezoidal Channel With Arc Angle

With the development of chinese market economy and growing tension of water resources,the rational use of water resources,increasing water use efficiency becomes an urgent problem to be solved.Irrigation as an important means to improve the utilization ratio of water resources and promote water-saving,the research of irrigation water facilities which matching irrigation area is of great significance.Paper focuses on non-throat flume on trapezoidal channel with arc angle,through Auto CAD establishes three dimensional model figure and based on Fluent6.3 large fluid calculation software RNG k-? turbulence model and VOF method.In order to establish a unified flow formula and provide the basis for flume design selection and optimization,this research undertaking comprehensive simulation experimental research on water flow movement under different conditions of non-throat flume on trapezoidal channel with arc angle.The major contents of the study spread out as follows:(1)According to known channel data based on critical theory and hydraulics knowledge,design flume and test programmes,and lay the foundation for numerical simulation of late by the establishment three dimensional model of non-throat flume on trapezoidal channel with arc angle.Through the error analysis of simulation flow and channel flow under the condition of different bottom slope and contraction ratio which selected in the programme,proved that the model and the corresponding parameters with higher reliability.(2)The relation curve between water level and discharge-influenced under different slope i and shrinkage ratio ? shows that slope i and shrinkage ratio ? has a great effect on the curve.For the same channel,as the throat width and contraction ratio decreases can form a unified and stable water level-discharge relationship in the context of large slope,the maximum slope can be up to i=1/2800.(3)The study the variation regularity of upstream backwater height,Froude number and head loss under different working conditions show that the effect of contraction ratio is significantly higher than the hydraulic characteristics of slope changes.Therefore,in order to improve the measurement precision,we should first select a smaller contraction to minimise head loss and channel backwater height when the bottom slope and contraction ratio is difficult to meet the requirements water facilities at the same time.(4)Paper explored the relationship between flow coefficient C and the flow index n,free flow coefficient k,and established flow formulas of different channels on the base of numerical experiments.Besides,with the regression analysis of established various channels of flow formulas with good correlation by the Matlab software and established uniform flow formula which is suitable for non-throat flume on trapezoidal channel with arc angle in different radius.Overall,the formula has a high precision measuring in the large range of 3.4449~33.1918 m3?s-1,the measuring error is less than 5%,which provided the basis for working out irrigation canal system plan and adjustment of water supply and distribution programme.