Analysis On Hydraulic Characteristics Of Lock Approach Channel And Water Conveyance System Of Medium And Low Hydraulic Head Lock

With the vigorously promote and build of “the belt and road”,water transport construction is also booming.The construction of the lock,which is the main passing dam building,has also been developed rapidly.According to incomplete statistics,the number of locks that has been built and under construction has reached more than 900 in our country.The hydraulic characteristics of the lock guide and water conveyance system are the key technologies that are suitable or not for their layout.Aiming at the arrangement of the lock guide and water conveyance system in the specific water conservancy project,we carried out a comprehensive and in-depth study through information research,summary analysis,hydraulic model test and numerical simulation method.Lock guide entrance area is an important area for connecting the waterway and the lock chamber,and its flow condition is directly related to whether the ship can enter and leave the lock safely.However,the cross-section of the channel area is usually changed by the influence of the terrain or the arrangement of the hub.In the area of the upstream lock guide,the cross-section is gradually shrinking,from the upstream waterway transition to the upstream lock guide;in the area of the downstream lock guide,the cross-section is gradually expanding,from the downstream lock guide transition to the downstream waterway.Therefore,in the lock guide entrance area often appear oblique flow,reflux and other adverse flow condition.This paper takes the controlling gate in the project of leading water from Yangtze to Huaihe River as an example,through 1:80 hydraulic model test and numerical simulation method,analyzes the navigable flow conditions in lock guide entrance area,and recommends the optimization scheme for the arrangement of the entrance area.In addition,the choice of the layout of the water conveyance system of the lock will affect the flow regime in the gate chamber,thus determining whether the ship in the gate chamber is safe,so it needs to conduct in-depth study.Lujiang lock is used in the gate of the long corridor side of the branch of the decentralized water delivery system,in this paper,the hydraulic characteristics,pressure characteristics and mooring force of the water conveyance system are studied by 1:30 hydraulic model test.The main research results are as follows:(1)Based on the hydraulic model test of the controlling gate,the navigable flow conditions of the lock guide entrance area are studied and analyzed.The results show that the flow conditions are good,the longitudinal flow rate,the lateral flow rate and the reflux flow rate are far less than the velocity limit in the specification,the layout of the hub is reasonable.(2)This paper establishing the mathematical model,carrying out the numerical simulation,and discussing the optimization scheme of the layout of the lock guide entrance area.The results show that the length of the entrance area is reduced to 200 m,and the whole hub is symmetrically arranged,the navigable flow conditions meet the limit requirements and the engineering quantity is small.(3)Based on the hydraulic model test of the lock,the hydraulic characteristics of the lock chamber,the pressure characteristics in the water supply corridor and the parking conditions of the ship and the fleet in the lock chamber are analyzed.The results show that the water flow in the chamber is relatively stable under various operating conditions,and there is no negative pressure in the water supply corridor,but the mooring force of the ship and the fleet appears over-standard phenomenon,so do a further optimization study,and finally give the opening method that make hydraulic parameters meet the requirements: when the lock is positively operating,the bilateral filling water is recommended to use more than 7min to open the valve,or use 6min speed,when the opening reaches 0.4,paused 2min to open the valve;the bilateral emptying water is recommended to use 5-6min to open the valve.When the lock is negatively operating,the hydraulic head is low,in order to improve the efficiency of water delivery,it is recommended to use 3min to open the valve.