A particle tracking-based method for optimizing engineering layout of waterway confluence areas

Abstract

The present invention relates to an engineering layout method for optimizing the confluence area of ​​a waterway based on particle tracking, and belongs to the technical field of inland navigation, discharge and energy dissipation. Find out the source of water flow in the confluence gate area and formulate a water flow combination plan; construct a three-dimensional water flow simulation model to ensure the accuracy and applicability of the model; construct a particle convection-diffusion model and set special boundary conditions; reveal the law of water flow movement and find out the reasons for the velocity distribution; and arrange energy dissipation and diversion engineering facilities based on the law of water flow movement. The present invention realizes the accurate simulation of the water flow movement process in different areas under different water flow combination conditions, the water flow movement route is clear and definite, and the flow state and velocity distribution are vivid and intuitive; the energy dissipation and diversion facilities have obvious interactions with the water flow, which is convenient for optimizing the location and scale of energy dissipation and diversion projects, achieving a better engineering combination, improving calculation efficiency, and saving engineering investment.

Description

Technical Field

[0001] The present invention relates to the technical field of inland river navigation and flow discharge and energy dissipation, and in particular to the technical field of an engineering layout method for optimizing a waterway confluence area based on particle tracking. Background Art

[0002] During inland navigation, water discharge waves, bubbles and whirlpools are prone to occur at locations such as channel confluences, ship lock pilot channels and gate areas, resulting in adverse water flow conditions such as excessive lateral flow velocity and large-scale backflow in the navigation area. In order to eliminate the adverse effects of lateral flow velocity and backflow velocity on ship navigation and ensure navigation safety, it is necessary to install energy dissipation or diversion facilities to reduce water flow velocity and improve water flow state.

[0003] At present, the layout and scale of energy dissipation and diversion facilities are generally determined by physical model test methods or numerical simulation calculation methods. For physical model test methods, the physical model is a reduced version of the prototype river, with clear physical concepts and intuitive images, so it is widely used, but it often requires a huge site, consumes a lot of equipment, materials and manpower, and the test cycle is long. In addition, if the model test studies a specific problem, changing the problem or boundary conditions often requires full or partial demolition, and the test cost is expensive. For numerical model simulation methods, two-dimensional and three-dimensional hydrodynamic models are generally used, which can better simulate the plane flow state of water flow, but for complex structures, only the plane or cross-sectional flow velocity distribution can be given, which cannot well reflect the law of water flow movement in a specific area. It is difficult to accurately analyze the reasons for the excessive lateral flow velocity and return flow velocity in the navigation area. When arranging energy dissipation and diversion engineering facilities, it is not targeted, and the layout and scale of energy dissipation and diversion engineering facilities need to be continuously adjusted. The optimal combination of energy dissipation and diversion engineering facilities is determined through a large number of trial calculations. The calculation of the three-dimensional model depends on the number and quality of the grids. The large-scale three-dimensional numerical simulation of the confluence requires a large number of grids, and the calculation time for each trial condition is long. A large amount of trial calculation work requires a lot of time and cost. Summary of the invention

[0004] The present invention provides a method for optimizing the engineering layout of a waterway confluence area based on particle tracking. The particle tracking method is used to simulate the three-dimensional water flow movement law, analyze the source and movement trajectory of particles in the excessive flow rate area, so as to optimize the layout and scale of energy dissipation and diversion projects.

[0005] A particle tracking-based method for optimizing the engineering layout of a waterway confluence area comprises the following steps:

[0006] Step S1, finding out the source and composition of water flow in the confluence gate area;

[0007] Step S2: constructing a three-dimensional water flow simulation model;

[0008] Step S3, constructing a particle tracking convection-diffusion model;

[0009] Step S4, finding out the law of water flow movement and tracking the source of regional water flow;

[0010] Step S5: Arrange energy dissipation and diversion engineering facilities.

[0011] Preferably, in step S1 of the present invention, the flood frequencies of tributaries and waterways are analyzed based on a long series of hydrological data to reasonably determine the water flow combination scheme.

[0012] Preferably, in step S2 of the present invention, different water flow sources are quantified as independent boundaries, and one or more groups of three-dimensional water flow motion simulation models are constructed; model parameter calibration and model applicability evaluation are performed, and the study area is modeled with three groups of different grid scale models, and appropriate grids and parameters are selected for simulation;

[0013] Preferably, in step S3 of the present invention, in the particle convection-diffusion simulation model, there are no particles in the study area in the initial state, particles with different marks and numbers are given at different boundaries, the particles do not attenuate or react to each other, and only follow the water flow.

[0014] Preferably, in step S4 of the present invention, the velocity and flow pattern diagram, lateral velocity diagram, etc. of the navigation area of ​​the confluence are drawn, the area where the lateral flow velocity is greater than the standard value is marked, the spatial distribution of various particles in the area is extracted, the source of the particles is traced, the law of water flow movement is analyzed, and the cause is analyzed.

[0015] Preferably, in step S5 of the present invention, energy dissipation and diversion engineering measures are set according to the distribution pattern and source of particles within the range of excessive flow rate, and the engineering layout and scale combination are optimized.

[0016] The present invention adopts the above technical scheme, which has the following advantages compared with the prior art: it realizes accurate simulation of the water flow movement process in different areas under different water flow combination conditions, the water flow movement route is clear and definite, and the flow state and flow velocity distribution are vivid and intuitive; the energy dissipation and diversion facilities have obvious interaction with the water flow, which is convenient for optimizing the location and scale of the energy dissipation and diversion facilities, achieving a better engineering combination, improving calculation efficiency, and saving engineering investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an operation flow chart of an engineering layout method for optimizing waterway confluence area based on particle tracking;

[0018] Figure 2 This is a plan view of the waterfall confluence area of ​​a waterway;

[0019] Figure 3 This is a structural diagram of the waterfall confluence area of ​​a certain waterway;

[0020] Figure 4 This is the flow pattern diagram of a certain waterway's waterfall and confluence;

[0021] Figure 5 This is the layout drawing of the waterfall energy dissipation and confluence diversion project of a certain waterway;

[0022] Figure 6 The flow pattern diagram after optimization of the layout of the waterfall and confluence engineering of a certain waterway. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is described in detail below with reference to the accompanying drawings:

[0024] like Figure 1 As shown, a method for optimizing the engineering layout of a waterway confluence area based on particle tracking includes the following steps:

[0025] Step S1, finding out the source and composition of water flow in the confluence gate area;

[0026] Step S2: constructing a three-dimensional water flow simulation model;

[0027] Step S3, constructing a particle tracking convection-diffusion model;

[0028] Step S4, finding out the law of water flow movement and tracking the source of regional water flow;

[0029] Step S5: Arrange energy dissipation and diversion engineering facilities.

[0030] Specific:

[0031] S1: Find out the source of water flow in the confluence area and determine the water flow combination plan

[0032] Sorting historical flood data, analyzing the source and magnitude of water flow, and combined flood encounter scenarios, and determining the design conditions and the most unfavorable navigation conditions analysis plan according to navigation regulations.

[0033] Specific example: At the confluence of a certain waterway, the flow rate is 100m3 at a 5-year return period. 3 / s, tributary flow rate once in five years 50m 3 / s, channel water level 10.0m. Figure 2 , the three-dimensional structure is shown in Figure 3 .

[0034] S2: Build a three-dimensional water flow simulation model to ensure model accuracy and applicability

[0035] Based on the layout structure of the hub building, a physical model of the building is drawn at a 1:1 ratio. The RNG k-ε model is used to simulate the turbulent structure of the flow field. According to the structure and boundary characteristics of the building, its entity is divided into three-dimensional grids. Sensitivity analysis is performed on the sizes and division methods of two adjacent grids until the sensitivity is less than the specification requirements. The model is verified by water level, flow rate, flow velocity and flow state. If the verification result does not meet the requirements, parameters such as roughness and viscosity coefficient are adjusted until the requirements are met to ensure the accuracy and applicability of the model.

[0036] Specific example: The model range is generally 500m upstream and 500m downstream of the center line of the intersection of the waterfall and the channel, and the river section about 300m long upstream of the tributary as the simulation range; the grid division method adopts the free grid method, all of which are block structured orthogonal grids, and the grid scale is 0.25-1.0m. Parts with detailed structure sizes less than 0.25m need to be encrypted, and the structure size needs to be significantly smaller than the size of a grid. The upstream inlet boundary of the model is the flow boundary, and the downstream outlet boundary is the pressure boundary. The standard wall function is used to treat the viscous bottom layer, and the fluid is set to be an incompressible fluid.

[0037] S3: Construct particle convection-diffusion model and set special boundary conditions

[0038] On the basis of the three-dimensional water flow simulation model, the particle module is coupled and a module is added as a boundary condition to construct a particle tracking convection-diffusion simulation model to simulate the water flow process and law in different regions. At the boundary of the tributary water inlet, the boundary section is divided into 2*2, 4*4, 10*10 or more unit grids (different numbers and shapes of cells are divided according to actual needs to reflect the flow state and flow velocity), and different unit grids are set with different marked and numbered particles.

[0039] Specific example: Taking the navigation condition with a return flow of 5 years as an example, a water flow simulation model and a particle convection-diffusion model are constructed to simulate the water flow movement and particle migration process. The upstream of the tributary is the flow boundary, and a constant flow of 50 m is given. 3 / s, and is divided into 4 cells of 4*4, with 4 marks, square (█), triangle (△), solid circle (●) and cross (┼) and corresponding numbered particles 1, 2, 3, 4; the upstream of the channel is the flow boundary, and a constant flow of 100 m is given 3 / s, no particles are set; the downstream of the channel is the water level boundary, and a constant water level of 10m is given.

[0040] S4: Reveal the laws of water flow and find out the causes of flow velocity distribution

[0041] Based on the simulation results of the particle tracking convection-diffusion model, the source and destination of water flow in different areas are explored, and the law of water flow movement is mastered. The velocity distribution cloud map is used to identify the area where the lateral velocity of the confluence navigation area is greater than the standard value, and the particle mark and number are identified to extract the spatial distribution of various particles in the area. According to the particle trajectory, the source of water flow in the area where the lateral velocity and backflow velocity exceed the standard is tracked, and the reason for the excessive velocity is analyzed.

[0042] Specific example: Draw the flow pattern and velocity distribution map of the waterway confluence area ( Figure 4 ), mark out the areas with lateral velocity > 0.5m / s (according to the velocity requirements of the specification), intercept different sections in this area, extract particles, analyze the lateral and vertical distribution of particles, track the source, movement route and law of particles, etc.; analyze the reasons for the excessive velocity, such as the large particle velocity, the large angle between the particle movement direction and the channel, etc.

[0043] S5: Arrangement of energy dissipation and diversion engineering facilities

[0044] According to the movement laws of the areas where the lateral velocity exceeds the standard or the areas with poor flow conditions and the reasons for the excessive flow rate, the flow state in the areas where the velocity exceeds the standard is improved by changing the particle flow direction and reducing the particle flow velocity, so as to reduce the lateral velocity value and range in the areas where the velocity exceeds the standard, quickly and reasonably arrange the energy dissipation and diversion engineering facilities, and optimize the engineering layout and scale.

[0045] Specific example: The guide wall diversion engineering measures are arranged at the confluence. The diversion measures reduce the angle between the triangle (△) marked particles and the waterway, and break up the solid circle (●) marked particles. The lateral flow velocity in the confluence area of ​​the waterway is significantly reduced, and the area exceeding the standard is significantly reduced, meeting the requirements of the specification. Figure 5 , the lateral velocity is Figure 6 .

[0046] The present invention realizes accurate simulation of water flow movement process in different areas under different water flow combination conditions. The water flow movement route is clear and definite, and the flow state and flow velocity distribution are vivid and intuitive. The energy dissipation and diversion facilities have obvious interaction with the water flow, which is convenient for optimizing the location and scale of the energy dissipation and diversion projects.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for optimizing the engineering layout of a waterway confluence area based on particle tracking, comprising the following steps: Step S1, find out the source and composition of water flow in the confluence gate area; find out the source of water flow in the confluence gate area, determine the water flow combination plan, sort the historical flood data, analyze the source and magnitude of water flow, and the flood encounter combination scenario, and determine the design condition and the most unfavorable navigation condition analysis plan according to the requirements of navigation regulations; the navigation condition with a return flow of 100m in 5 years, the channel flow is 100m 3 / s, tributary flow rate once in five years 50m 3 / s, channel water level 10.0m; Step S2: Construct a three-dimensional water flow simulation model; ensure the accuracy and applicability of the model. Based on the layout structure of the hub building, draw a 1:1 building entity model, use the RNGk-ε model to simulate the turbulent structure of the flow field, divide the entity into three-dimensional grids according to the building structure and boundary characteristics, and perform sensitivity analysis on the two adjacent grid sizes and division methods until the sensitivity is less than the specification requirements. Verify the model through water level, flow rate, flow velocity and flow state. If the verification result does not meet the requirements, adjust the roughness and viscosity coefficient until the requirements are met to ensure the accuracy and applicability of the model. The simulation range is 500m upstream and 500m downstream of the center line where the waterfall intersects the waterway, and the 300m long river section upstream of the tributary. The grid division method adopts the free grid method, all of which are block structured orthogonal grids. The grid scale is 0.25-1.0m, and the parts with detailed structure size less than 0.25m need to be encrypted. The upstream inlet boundary of the model is the flow boundary, and the downstream outlet boundary is the pressure boundary. The standard wall function is used to process the viscous bottom layer, and the fluid is set as an incompressible fluid. Step S3: construct a particle tracking convection-diffusion model; Setting special boundary conditions Based on the three-dimensional water flow simulation model, the particle module is coupled as the boundary condition to build a particle tracking convection-diffusion model to simulate the water flow process and law in different regions; at the boundary of the tributary water inlet, the boundary section is divided into 2*2, 4*4, 10*10 or more unit grids, and different numbers and shapes of cells are divided according to actual needs to reflect the flow state and flow velocity of the water flow, and different unit grids are set with different markings and numbered particles; Construct a water flow simulation model and a particle tracking convection-diffusion model to simulate water flow and particle migration. The upstream of the tributary is the flow boundary, and a constant flow of 50m is given. 3 / s, and divided into 4 cells of 4*4, given 4 marks of square, triangle, solid circle and cross and corresponding numbered 1, 2, 3, 4 particles; the upstream of the channel is the flow boundary, given a constant flow of 100m 3 / s, no particles are set; the downstream of the channel is the water level boundary, and a constant water level of 10m is given; Step S4: Find out the law of water flow movement and track the source of regional water flow; reveal the law of water flow movement, find out the reason for flow velocity distribution, find out the source and destination of water flow in different regions based on the simulation results of particle tracking convection-diffusion model, and master the law of water flow movement; use the flow velocity distribution cloud map to mark the area where the lateral flow velocity in the confluence navigation area is greater than the standard value, identify the particle mark and number to extract the spatial distribution of various particles in the area, track the source of water flow in the area where the lateral flow velocity and backflow velocity exceed the standard according to the particle trace, and analyze the reason for the flow velocity exceeding the standard; Step S5: Arrange energy dissipation and diversion engineering facilities; Arrange energy dissipation and diversion engineering facilities. According to the movement law of the lateral velocity exceeding area or the area with bad flow pattern and the reason for the velocity exceeding the standard, the flow pattern of the exceeding area is improved by changing the particle flow direction and reducing the particle flow velocity, so as to reduce the lateral velocity value and range of the exceeding area, quickly and reasonably arrange energy dissipation and diversion engineering facilities, and optimize the engineering layout and scale; Guide wall diversion engineering measures are arranged at the confluence. The diversion measures reduce the angle between the triangular marker particles and the waterway and break up the solid circle marker particles. The lateral flow velocity in the confluence area of ​​the waterway is significantly reduced, and the area exceeding the standard is significantly reduced, meeting the requirements of the specifications.

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