Study On Improvement Of Inlet Flow Pattern Of Side-inlet Pumping Station Based On Hollow Rectifying Sill

In hydraulic engineering,due to the topography,site and other factors,the form of side-inlet pumping station was often used,which easily led to poor inlet flow in the pumping station and affected the inflow of the inlet channel.In order to improve the inlet flow pattern of such pumping stations,a physical mode 1 and a mathematical model were established based on a side-inlet pumping station in Zhejiang province.Through the comparison and selection of different rectification measures,it is found that the rectification effect of the rectifying hollow sill is better.Therefore,the rectifying sill is deeply analyzed,and the rectification measures of the hollow rectifying hollow sill were put forward,with emphasis on the optimization of the opening parameters of the rectifying hollow sill.The physical model was used to select seven hollow rectifying sill with different hole-to-height ratios.The results showed that when hollow rectifying sill were set,if the hole-to-height ratio was too small,the hollow part was also too small to form sufficient straight flow to affect the falling flow on the sill;when the ratio of hole-to-height was too high,the effect of hollow sill hole on downstream rectification of through-hole flow was reduced,and the effect of hollowed-out hole on rectification of through-hole flow was reduced,as a result,the rectifying effect of the hollow rectifying sill was decreased.Therefore,with the increase of the hole-to-height ratio,the rectification effect was strengthened first and then weakened.When the hole-to-height ratio was 0.6,the vortex and backflow area of the forebay basically disappeared,and there was no obvious deviation in inlet pool,at the same time,the maximum velocity uniformity at this time was 95.5%,which indicated that the rectification effect reached the best at this time.In order to further analyze the parameters of the hollow rectifying sill,a mathematical model is constructed,and the reliability of the mathematical model is verified by the results of the physical model,then the mathematical model is used to study the design parameters of the hollow rectifier bottom sill,such as the hole-to-height ratio and the hole-to-width ratio.The experimental results showed that,from the aspect of hole-to-height ratio,the result was basically consistent with the physical model after extension of the scheme.when the hole-to-height ratio was 0.6,the flow pattern in the forebay was better and the velocity uniformity was increased by 13.24%compared with that when the hole-to-height ratio was 0.From the aspect of hole-to-width ratio,as well as hole-height ratio,the rectification effect of hollow sill and hole-width ratio were not in direct or inverse proportion.The numerical simulation results showed that with the increase of hole-to-width ratio,the rectification effect first improved,and then deteriorated,the rectification effect was best when the hole-to-width ratio was 1/3.Based on the results of numerical simulation and physical model,the hollow rectifying sill with holes in the bottom sill had better rectification effect than the common sill.At the same time,when the hole-to-height ratio was 0.6 and the hole-to-width ratio was 1/3,the rectification effect of hollow sill is the best,which had certain reference and guiding significance for the design of rectifying sill of similar pumping stations.