| In the design of spillway engineering,when the curve drain section in the curve exists and the axis of the curve has a relatively small radius,effective engineering measures should be taken to improve the flow of the curve in the curve section of the drain to reduce the difference between the concave-convex shore water surface and make the flow of the curve even.In order to improve the flow condition of the spillway bend,the inclined sill is one of the effective engineering measures.However,under the condition of high speed water flow,the water-free low-pressure zone may appear on the backwater side of the impervious beveling,causing cavitation,thus causing damage to the beveling.Therefore,based on the water flow adjustment effect of the bend,and from the Angle of safe and reliable operation of the inclined sill,the permeable inclined sill is proposed.At present,there are many researches on the traditional solid beveling sill,but no systematic research results have been found on the permeable beveling sill.The model experiment scheme mainly considers three factors: the number of curves,the height and the permeability of the permeable sill.Even decorate,including waterproof inclined sill in river bend Angle 45 °,decorate the number three schemes(3,4,5),arrangement height have three schemes(20 mm,30 mm,40 mm),the height of each scheme has three oblique sill permeable rate and curve comparison scheme of engineering measures,The permeability is adjusted by controlling the diameter of the water hole.a total of 16 hydraulics model.Based on the experimental data of water level,flow rate and dynamic water pressure of different flow rates in each experimental scheme,the water flow characteristics of spillway bend with permeable inclined sill are analyzed,and the main results are as follows.(1)The effect of water flow improvement in the bend: the experimental data were measured,the charts were drawn,and the conclusions were drawn.According to the experimental scheme,measured data and calculated froude number,the froude number before entering the bend is greater than 1 for rapids,the froude number in the bend is less than 1 for slow flow,and the froude number after exiting the bend is rapids.Froude number between 0.6 and 0.9 is slow flow before entering the bend,froude number less than 1 is slow flow,and it is rapids after entering the bend.Compared with no permeable beveling in the bend after placing permeable beveling,the surface effect of the bend is improved significantly,which reduces the maximum surface difference of the cross section and improves the evenness of the surface of the bend.In general,the more inclined sill bars on the curved section,the better the surface improvement effect.In general,the higher the height of the permeable inclined sill,the better the surface improvement effect.In some cases,the permeable inclined sill with a height of 30 mm is higher than 40 mm.1)the permeability of inclined sill under the condition of lower inclined sill has a great influence on the improvement of the surface of the curved road.The lower the permeability,the better.2)the improvement effect of water surface between different permeability of the medium-high sill is not much different.Based on the experimental data of permeable beveling,this paper corrects the traditional formula for calculating the maximum surface difference of curved cross-section,and puts forward the formula for calculating the maximum surface difference of curved cross-section under the condition of permeable beveling considering such factors as height,quantity and permeability of permeable beveling.(2)The effect of the water slope on the flow rate of the bend channel: Tecplot postprocessing software was used to process the longitudinal velocity data,and the longitudinal velocity distribution cloud map of curved road with different quantity,height and permeability was obtained.By using the origin software,the flow velocity of the horizontal velocity,along the section of the horizontal velocity,and the vertical velocity distribution,the analysis is concluded.After the arrangement of the water slope in the bend,the velocity of the bottom flow is obvious,and the flow velocity of the bottom flow is obvious.The flow velocity of the imported to the export process is fluctuating but the overall increase is small.The slope of the water is changing the direction of the horizontal velocity of the Central Line of the bend canal,the horizontal velocity of the bottom of the Central Line increases,the horizontal velocity of the surface decreases,but the overall reduction of the lateral circulation in the bend is reduced,and the surface uniformity is improved.(3)The pulse pressure of the curved side plate of the bending road under the water slope of the water slope is under the pressure: The pressure data analysis of the pulse pressure of the bending road plate is carried out,and the high permeability of the water penetration is affected by the pressure of the different quantity of high permeability,and the pressure fluctuation is small compared with the non-engineering measures.(4)The hydraulic pressure of the water and the back water of the water : Slope of the water,using the data measured by the pressure tube,the analysis is obtained by the water slope,and the pressure of the water pressure is less than the corresponding height of the corresponding height,and the water pressure is strong.In the middle of the back surface of the water,the pressure of the water pressure is greater than that of the non-permeable water,and the water pressure is stronger than that of the back water surface.The pressure of the water is stronger than the water pressure when the water is under the water.Compared with the non-permeable water slope,the pressure of the water surface is reduced and the high pressure of the back water is strong and the improvement of the water pressure can reduce the hydraulic pressure of the water surface and the back surface of the water,which can help to improve the stability of the water trap.However,when the curve is less flow,the middle position of the bend is small and negative. |
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