Peak shaving power station downstream non-safe navigable water area identification method and system and medium

Abstract

The invention relates to a peak shaving power station downstream non-safe navigable water area identification method and system and a medium, and the method comprises the steps: building a peak shaving power station downstream river channel one-dimensional and two-dimensional coupling hydrodynamic mathematical model; determining a combination mode of a proposed condition and a water flow boundary condition of a typical peak regulation process of the downstream of the hydropower station; simulating and calculating downstream on-way hydrodynamic conditions of the power station under different peak shaving processes; calculating a downstream non-safe navigation index of the peak regulation power station; and identifying the downstream non-safe navigable water area of the peak shaving power station. According to the method, on one hand, the change condition of downstream hydrodynamic force of the peak regulation power station can be analyzed, on the other hand, the influence condition of the peak regulation process on downstream navigation conditions can be recognized, non-safe navigation water areas of the peak regulation power station in different discharge flow processes can be judged, and a research basis is provided for hub power generation and navigation scheduling of mountain rivers.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of water conservancy engineering navigation, and in particular to a method and system for identifying non-safety navigation water areas downstream of a peak-regulating power station and a medium. BACKGROUND

[0002] Navigation is one of the important development goals of a water conservancy hub project. In order to ensure that the river navigation can normally operate after the water conservancy hub is built, specific requirements need to be proposed for the navigation flow conditions, including the navigation flow, the navigation water level, the maximum allowable flow velocity, and the local water surface gradient. Under normal circumstances, it is required that the water flow surface velocity and the water level change rate are controlled within a reasonable range while ensuring sufficient navigation water depth, and meet the corresponding navigation standards. The peak-regulating power station frequently adjusts the discharge mode, which causes the downstream water flow conditions to change over time. This non-constant flow process inevitably affects the hydrological conditions downstream of the water conservancy hub, so that the water level fluctuation and the flow velocity of the region are increased compared with the natural state of the river, thereby threatening the navigation conditions and the safety of the parked ships. Therefore, on the river with a peak-regulating power station or other water conservancy facilities, it is particularly important to establish an effective dispatching management system to coordinate the power generation and navigation requirements and prevent the sudden change of the discharged flow from affecting the navigation safety.

[0003] At present, the discharged flow of the peak-regulating power station in a short period of time cannot meet various boundary conditions set in the design stage. Therefore, the numerical simulation technology needs to be used to evaluate the changes of the navigation channel flow conditions in different peak-regulating stages. By combining the relevant navigation flow standard requirements, a more scientific and reasonable dispatching scheme is developed. This will provide solid technical support for the safe operation of the water conservancy hub project and ensure stable navigation conditions downstream of the hub. SUMMARY

[0004] The purpose of the embodiments of the application is to provide a method and system for identifying non-safety navigation water areas downstream of a peak-regulating power station and a medium, which can analyze the hydrodynamic changes downstream of the peak-regulating power station, that is, judge the non-safety navigation water areas in different discharged flow processes of the peak-regulating power station, and provide research basis for hub power generation, navigation dispatching and other aspects of mountainous rivers.

[0005] To achieve the above-mentioned purpose, the application provides the following technical solutions:

[0006] In a first aspect, the embodiments of the application provide a method for identifying non-safety navigation water areas downstream of a peak-regulating power station, comprising the following steps:

[0007] Step 1. Establishing a one-dimensional and two-dimensional coupled hydrodynamic mathematical model of the river downstream of the peak-regulating power station;

[0008] Step 2. Determining the proposed conditions and the combination mode of the flow boundary conditions of the typical peak-regulating process downstream of the hydropower station;

[0009] Step 3. Simulate the water dynamic conditions along the power plant downstream under different peak shaving processes;

[0010] Step 4. Calculate the non-safety navigation indicators downstream of the peak shaving power plant;

[0011] Step 5. Identify the non-safety navigation water area downstream of the peak shaving power plant.

[0012] The step 1 of establishing the one-dimensional and two-dimensional coupled hydrodynamic mathematical model of the river downstream of the peak shaving power plant comprises the following steps:

[0013] Step 11. Collect fixed section and underwater topography observation data of the river section and surrounding area downstream of the peak shaving power plant, and rely on the actual discharge process of the power plant and the hydrological data of the control station of the main stream and tributaries as the data basis of the one-dimensional and two-dimensional coupled hydrodynamic mathematical model;

[0014] Step 12. Divide the research river section downstream of the peak shaving power plant into a series of calculation grid units along the length direction, and the grid division should be determined according to the characteristics of the river section and the simulation accuracy requirements, and the underwater topography data is correspondingly interpolated into the divided grid units to form the model calculation grid embedded with topography data;

[0015] Step 13. According to the data basis of step 11 and the model grid of step 12, a one-dimensional hydrodynamic mathematical model of the river section downstream of the peak shaving power plant is constructed, characterized in that the basic equation is:

[0016] Water flow continuity equation:

[0017] Water flow momentum equation:

[0018] Branch point water mass continuity equation:

[0019] Branch point momentum continuity equation:

[0020] The physical meaning and unit of each symbol in the above equation are: x is the flow process; Q is the flow; z is the water level; q is the interval inflow; u is the branch flow velocity; U is the main stream flow velocity; B is the river width; t is the time; A is the cross-sectional flow area; R is the hydraulic radius; n is the roughness coefficient; β is the momentum correction coefficient; M is the number of branch points in the river network, L(m) is the number of river sections connected to the branch point m, Z m,l is the water level of the endpoint of the lth river section connected to the branch point m; Q m,l is the flow into or out of the branch point from the lth river section connected to the branch point, and the superscript n+1 represents the calculation period;

[0021] According to the calculation result of the one-dimensional water dynamic mathematical model of the downstream river section of the constructed peak shaving power station, water flow boundary conditions are provided for a two-dimensional water dynamic mathematical model, and the two-dimensional water dynamic mathematical model is characterized in that the basic equation is:

[0022] In the Cartesian coordinate system, the two-dimensional shallow water equation based on the average water depth is briefly written as:

[0023]

[0024]

[0025]

[0026] In the formula, is the water depth; and are flow velocities in the x and y directions respectively; and are source terms; , are source terms.

[0027] Step 14. According to the collected hydrological data of the observation section along the river channel downstream of the peak shaving power station, the hydrodynamic parameters of the established one-dimensional and two-dimensional water dynamic mathematical models of the downstream river section of the peak shaving power station are calibrated, and the simulation results are verified.

[0028] The combination mode of the determined conditions and water flow boundary conditions of the typical peak shaving process downstream of the hydropower station in step 2 comprises the following steps:

[0029] Step 21. Collect the water level and flow data of the typical control hydrological station in the near-dam section downstream of the peak shaving power station for many years, and divide the flow level range according to the peak shaving discharge process of the peak shaving power station for many years;

[0030] Step 22. According to the flow level divided in step 21, the frequency of each flow level appearing in the peak shaving discharge process of the peak shaving power station for many years is calculated, and all flow levels with an appearance frequency of more than 30% are used as the flow boundary conditions of numerical simulation;

[0031] Step 23. According to the water level and flow data collected in step 21, a water level-flow relationship curve is drawn; according to the peak shaving discharge classification of the peak shaving power station divided in step 22, the corresponding model lower boundary water level process is given by corresponding water level-flow relationship curve points, to form a combination of the corresponding upper boundary flow process and lower boundary water level process.

[0032] The simulation calculation of the water dynamic conditions along the downstream of the power station under different peak shaving processes in step 3 comprises the following steps:

[0033] Step 31. According to the actual discharge process of the peak shaving power station in previous years and the water level change of the lower boundary observation section, different peak shaving flows are sorted and the water flow condition combinations with higher occurrence frequency are screened as typical peak shaving water flow conditions, which are the basis for subsequent numerical simulation calculation schemes;

[0034] Step 32. According to the established one-dimensional and two-dimensional coupled hydrodynamic mathematical model of the downstream river section of the peak shaving power station, the typical peak shaving water flow conditions in step 31 are numerically simulated, and the corresponding changes of water level, water surface slope and average flow velocity along the section are sorted out;

[0035] Step 33. Calculate the two-dimensional water flow process downstream of the power station under the typical peak shaving water flow conditions, plot the along-track flow lines, and identify the water area with backwater phenomenon downstream of the peak shaving power station, and the radius and area of the backwater area are and respectively.

[0036] The step 4 of calculating the non-safety navigation index downstream of the peak shaving power station comprises the following steps:

[0037] Step 41. Sort the discharge data of the peak shaving power station in previous years to obtain the instantaneous minimum discharge in previous years , and the corresponding water level is , according to the content of the inland navigation standard, the highest navigation water level is designed as , and the design navigation water level range of the peak shaving power station is ;

[0038] Step 42. Calculate the change process of the average flow velocity along the section downstream of the power station under the typical peak shaving water flow conditions, and select 3m / s as the flow velocity identification threshold of the unsafe water area according to the content of the inland navigation standard, that is:

[0039] When , the section is identified as a non-safety navigation water area;

[0040] When , the section is identified as a suitable navigation water area;

[0041] Step 43. According to the radius and the area of the identified backwater area, the proportion of the water area with flow velocity exceeding 3m / s in the backwater area is further identified as , which is the range of the non-safety navigation area in the backwater area downstream of the peak shaving power station.

[0042] The step 5 of identifying the non-safety navigation water area downstream of the peak shaving power station comprises the following steps:

[0043] Step 51. When the peak shaving processes are respectively ( , When ), the corresponding criterion for determining the design navigation water level is:

[0044] when hour, The cross-section is within the suitable navigable water level range;

[0045] when or hour, The cross-section does not meet the suitable navigable water level range;

[0046] Step 52. Under the condition that the water level meets the navigation requirements, further determine the range of safe navigable waters based on the water flow velocity. When, then identify The cross-section is a safe navigable waterway;

[0047] Step 53. Under the conditions of water level and current velocity for navigation, further based on the conditions of flow pattern for navigation, if the current velocity in the backwater area identified by the flow trace exceeds 3 m / s, it is judged as an unsafe navigation area, and the corresponding percentage of the unsafe navigation area in the backwater area is given. ;

[0048] Step 54. Provide details for each peak-shaving process ( , The scope of unsafe navigation waters and their proportion in the downstream waters of peak-shaving power plants.

[0049] Secondly, embodiments of this application provide a system for identifying unsafe navigable waters downstream of a peak-shaving power station, including a memory and a processor. The memory includes a program for identifying unsafe navigable waters downstream of a peak-shaving power station. When the program for identifying unsafe navigable waters downstream of a peak-shaving power station is executed by the processor, it implements the steps of the method described above.

[0050] Thirdly, embodiments of this application provide a computer-readable storage medium storing program code, which, when executed by a processor, implements the steps of the method for identifying unsafe navigable waters downstream of a peak-shaving power station as described above.

[0051] Compared with the prior art, the beneficial effects of the present invention are:

[0052] The method combines existing observation data, constructs a one-two-dimensional coupled hydrodynamic mathematical model suitable for the downstream river section of the peak shaving power station, and can give the distribution of water dynamic elements such as water level change, water surface gradient change and cross-section average flow velocity change along the river under the corresponding water flow boundary conditions in combination with the peak shaving process of the power station. At the same time, it can also analyze the non-safety navigation river section downstream of the peak shaving power station and the proportion of the whole river section through simulation calculation results. The computer has clear mechanism, clear implementation process and feasible technical means. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0054] Figure 1 The flow chart of a non-safety navigation water area identification method downstream of a peak shaving power station for the embodiments of the present application;

[0055] Figure 2 The water level change along the river under the constant flow condition of the BHT reservoir area;

[0056] Figure 3 The flow velocity change along the river under the constant flow condition of the BHT reservoir area;

[0057] Figure 4 The water level change along the river under the peak shaving condition of the BHT reservoir area;

[0058] Figure 5 The flow velocity change along the river under the peak shaving condition of the BHT reservoir area;

[0059] Figure 6 The flow trajectory distribution along the river section at the tail of the BHT reservoir. DETAILED DESCRIPTION

[0060] The technical solutions in the embodiments of the present application will be described below in combination with the drawings in the embodiments of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0061] The terms "comprise", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0062] The terms "first", "second", and the like, merely distinguish one entity or action from another, without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0063] As Figure 1 shown in a method for identifying non-safety navigable water areas downstream of a peak-shaving power station, comprising the following steps:

[0064] Step 1, a one-dimensional and two-dimensional coupled hydrodynamic mathematical model of the river downstream of the peak-shaving power station is established, and the implementation is as follows,

[0065] Step 11. Collect fixed section and underwater topographic observation data of the river section downstream of the peak-shaving power station and the surrounding area, and rely on the actual discharge process of the power station and the hydrological data of the control station of the main and branch streams as the data basis of the one-dimensional and two-dimensional coupled hydrodynamic mathematical model;

[0066] Step 12. Divide the research river section downstream of the peak-shaving power station into a series of calculation grid units along the length direction, and the grid division should be determined according to the characteristics of the river section and the simulation accuracy requirements. The underwater topographic data is correspondingly interpolated into the divided grid units to form a model calculation grid embedded with topographic data;

[0067] Step 13. According to the data basis of step 11 and the model grid of step 12, a one-dimensional hydrodynamic mathematical model of the river section downstream of the peak-shaving power station is constructed, characterized in that the basic equation is:

[0068] The water flow continuity equation is:

[0069] The water flow momentum equation is:

[0070] The water flow continuity equation at the branch point is:

[0071] The water flow continuity equation at the branch point is:

[0072] In the above equations, the physical meaning and unit of each symbol are as follows: x is flow; Q is flow rate; z is water level; q is interval inflow; u is confluence flow velocity; U is main flow velocity; B is river width; t is time; A is cross-sectional flow area; R is hydraulic radius; n is roughness coefficient; β is momentum correction coefficient; M is the number of branch points in the river network, L(m) is the number of river sections connected to branch point m, Z m,l is the water level at the end of the lth river section connected to branch point m; Q m,l is the flow into or out of the branch point from the lth river section connected to the branch point, and the superscript n+1 indicates the calculation period.

[0073] According to the calculation results of the one-dimensional hydrodynamic mathematical model of the downstream river section of the constructed peak-shaving power station, water flow boundary conditions are provided for the two-dimensional hydrodynamic mathematical model. The two-dimensional hydrodynamic mathematical model is characterized in that the basic equation is:

[0074] In the Cartesian coordinate system, ignoring the effects of the slope pressure, Reynolds stress, and dispersion in the momentum equation, the two-dimensional shallow water equation based on depth-averaged can be simplified as:

[0075]

[0076]

[0077]

[0078] In the formula, is the water depth; and are the flow velocities in the x and y directions, respectively; , are source terms, and the expressions are:

[0079]

[0080]

[0081] In the formula, is the atmospheric pressure at the water surface; is the bed elevation; and are the forces of wind load, and the expressions are:

[0082]

[0083]

[0084] In the formula, is the air density; and V10 is the wind speed at 10 m above the water surface; Cd is the drag coefficient. and is the geostrophic Coriolis force, in the northern hemisphere expressed as:

[0085]

[0086]

[0087] where, is the Coriolis coefficient, ; is the angular velocity of the earth's rotation, . is the latitude.

[0088] , is the bottom bed resistance, expressed as:

[0089]

[0090]

[0091] where, is the roughness.

[0092] Equations (1), (2) and (3) are written in vector form as:

[0093]

[0094] where, , and are the partial derivatives with respect to time, space and directions, respectively,

[0095]

[0096]

[0097] Step 14. According to the collected hydrological data of the observation section along the river course downstream of the peak-regulating power station, the hydrodynamic parameters of the established one-dimensional and two-dimensional hydrodynamic mathematical model of the river section downstream of the peak-regulating power station are calibrated, and the simulation results are verified.

[0098] Step 2, determine the proposed conditions and water flow boundary condition combination mode of the typical peak-regulating process downstream of the hydropower station, the implementation is as follows,

[0099] Step 21. Collect the water level and flow data of the typical control hydrological station near the dam section downstream of the peak-regulating power station for many years, and divide the flow level range according to the peak-regulating discharge process of the peak-regulating power station for many years.

[0100] Step 22. According to the flow level divided in step 21 of claim 1, the frequency of each flow level in the peak shaving power station's annual discharge process is calculated. When the frequency is more than 30%, it is considered that the flow level is a frequent level in the downstream of the peak shaving power station. Therefore, all flow levels with a frequency of more than 30% are taken as the flow boundary conditions of numerical simulation.

[0101] Step 23. According to the water level and flow data collected in step 21 of claim 1, a water level-flow relationship curve is drawn; according to the peak shaving power station discharge classification in step 22 of claim 1, the corresponding model lower boundary water level process is given by corresponding water level-flow relationship curve points, to form a combination of the corresponding upper boundary flow process and lower boundary water level process.

[0102] Step 3, simulate the downstream water power conditions of the power station under different peak shaving processes, which is realized as follows,

[0103] Step 31. According to the actual discharge process of the peak shaving power station in the past years and the water level change of the lower boundary observation section, the different peak shaving flows are sorted and the high-frequency flow condition combinations are screened as typical peak shaving flow conditions, which are the basis for subsequent numerical simulation calculation schemes.

[0104] Step 32. According to the one-dimensional and two-dimensional coupled hydrodynamic mathematical model of the downstream river section of the peak shaving power station established in claim 3, the typical peak shaving flow conditions in step 31 are numerically simulated, and the corresponding changes of water level, water surface slope and average flow velocity along the section are sorted out.

[0105] Step 33. According to claim 4, the two-dimensional flow process of the downstream of the peak shaving power station under the typical peak shaving flow conditions is calculated, the flow trajectory is plotted, and the water area with backwater phenomenon in the downstream of the peak shaving power station is identified, and the radius and area of the backwater area are and .

[0106] Step 4, calculate the non-safety navigation index of the downstream of the peak shaving power station, which is realized as follows:

[0107] Step 41. The discharge data of the peak shaving power station in the past years is sorted out, and the annual instantaneous minimum discharge is , and the corresponding water level is . According to the content of "Inland Navigation Standard" (GB 50139-2014), the design maximum navigation water level can be taken as the normal storage level of the hub; the design minimum navigation water level adopts the water level corresponding to the instantaneous minimum discharge of the hub . Therefore, the design navigation water level range of the peak shaving power station is .

[0108] Step 42. Calculate the average flow velocity variation process of the downstream cross-section of the power station under typical peak shaving water flow conditions according to Step 3. According to the content of “Inland Navigation Standard” (GB 50139-2014), select 3 m / s as the flow velocity identification threshold of unsafe water area, that is:

[0109] When , it is identified that the cross-section is an unsafe navigable water area.

[0110] When , it is identified that the cross-section is a suitable navigable water area.

[0111] Step 43. According to the backwater area radius (R) and area (S) identified in Step 33, further identify the area ratio of water area with flow velocity exceeding 3 m / s in the backwater area , , , , which is the range of unsafe navigable area in the backwater area downstream of the peak shaving power station.

[0112] Step 5, identify the unsafe navigable water area downstream of the peak shaving power station, the implementation is as follows,

[0113] Step 51. According to Step 41, when the peak shaving process is (V1, V2) respectively, , , the corresponding design navigation water level discrimination standard is:

[0114] When , the cross-section meets the suitable navigation water level category. When

[0115] or , the cross-section does not meet the suitable navigation water level category. Step 52. Under the water level navigation condition of Step 51, further judge the safe navigable water area range according to Step 42 according to the flow velocity, if , it is identified that the cross-section is a safe navigable water area.

[0116] Step 53. Under the water level navigation condition of Step 51 and the flow velocity navigation condition of Step 52, further according to the flow state navigation condition of Step 43, if the flow velocity in the backwater area identified according to the flow trajectory exceeds 3 m / s, it is judged as an unsafe navigable water area, and the corresponding unsafe navigable backwater water area area ratio is given.

[0117]

[0118] ​​​​​Step 54. Based on steps 51, 52, and 53, provide the results for a specific peak-shaving process ( , The scope of unsafe navigation waters and their proportion in the downstream waters of peak-shaving power plants.

[0119] The calculation scope of the two-dimensional coupled hydrodynamic mathematical model is the BHT reservoir area, with a main stream length of approximately 172 km. The model calculation considers the confluence process of tributaries such as PDH, XJ, and HSH. More than 200 cross-sections were arranged along the main stream of the Jinsha River, with cross-section spacing ranging from 0.4 km to 2.2 km.

[0120] The one-dimensional unsteady flow mathematical model embeds the reservoir scheduling relationship into the relationship mode between water level and flow in the river section equation, thus forming a reservoir scheduling calculation mode. It is coupled and solved with the river channel and river network, and the scheduling calculation is stable and can accurately control the water level and flow process at the dam site during the scheduling process.

[0121] If the main stream and tributaries of the reservoir are each considered as a single channel, and the confluence point of the channel is called a distributary, then the model should include two parts: the water and sediment movement equations for a single channel and the distributary connection equations.

[0122] (1) Equation of water flow in a single river channel

[0123] Continuity equation for water flow:

[0124] Water flow equation:

[0125] In the formula, β is the momentum correction coefficient.

[0126] (2) Equation for connecting the points of inversion

[0127] Continuity equation for water volume at inlets:

[0128] The momentum continuity equation at the confluence point:

[0129] The physical meanings and units of each symbol are as follows: x is the flow rate; Q is the flow rate; z is the water level; q is the inflow of the interval; u is the velocity of the confluence and branch flow; U is the velocity of the main stream; B is the river width; t is the time; A is the cross-sectional area; R is the hydraulic radius; n is the roughness coefficient; β is the momentum correction coefficient; M is the number of distributaries in the river network; L(m) is the number of river segments connected to distributary m; Z m,l Q represents the water level at the endpoint of the l-th river segment connected to the distributary point m; m,l The flow rate of the l-th river segment connected to the distributary m into or out of the distributary is given by the superscript n+1, which indicates the calculation period.

[0130] (3) Reservoir flood routing equation

[0131] The reservoir flood routing equation mainly adopts the water balance equation. In a calculation period, the difference between the reservoir water volume and the discharge volume is the change of the reservoir storage volume in the period, and the formula is as follows:

[0132]

[0133] In the formula, and are the inflow at the beginning and end of the calculation period, respectively; is the average inflow in the calculation period, which is the average value of and ; and are the discharge at the beginning and end of the calculation period, respectively; is the average discharge in the calculation period; and are the reservoir storage volume at the beginning and end of the calculation period, respectively; is the difference between and ; is the calculation period.

[0134] When the reservoir inflow hydrograph is known, and are known, and and are the initial conditions at the beginning of the calculation period. Combined with the input flow regulation target at the dam site, i.e. the future discharge hydrograph, the reservoir storage volume is calculated, and the reservoir water level process is derived by means of the reservoir volume characteristic curve , realizing the reservoir flood routing.

[0135] (4) Discrete solution

[0136] The control equation in (1) above is discretized by using the finite volume method of Godunov format.

[0137] (5) Branch point solution

[0138] Branch point flow:

[0139] The water flow equation is solved by using a three-level solution method. It is assumed that there are sections in a river section. The following micro-segment equations obtained by difference are sequentially self-eliminated, and the unknowns are concentrated at the branch point through the recursive relationship, so that the water level-flow relationship of the first and last sections of the river section can be obtained. The three-level river network algorithm can well accommodate various special calculation modes, and is convenient for calculation format consistency and calculation stability.

[0140] ​

[0141] wherein the coefficients , , , , , are obtained by recursive formula.

[0142] By substituting the boundary conditions and the water level-flow relationship of the head and tail sections of each river section into the bifurcation connection equation, an algebraic equation group with the water levels of each bifurcation point of the reservoir trunk and branch river channels as unknowns can be established. The water levels of each bifurcation point are obtained by solving the equation group, and the end point flow of each river section and the water level and flow in each river section can be obtained by step-by-step back substitution.

[0143] (6) Determination of roughness coefficient

[0144] The roughness coefficient is a comprehensive coefficient reflecting the water flow condition and the riverbed morphology, and its influence is mainly related to the river bank, main channel, beach, sediment particle size, sand wave and artificial structures, etc. The resistance problem is reflected through the roughness. When the river channel is scoured, the riverbed is coarsened, and the roughness is increased. Conversely, when the river channel is silted, the riverbed is fined, and the roughness is decreased. The model is calibrated with the initial roughness according to the measured water level-flow data, and the roughness is tested step by step in several flow levels of each river section.

[0145] (7) According to the calculation results of the one-dimensional hydrodynamic mathematical model of the downstream river section of the WDD hydropower station constructed, the flow boundary conditions are provided for the two-dimensional hydrodynamic mathematical model of the downstream near-dam section of the WDD. The basic equation of the two-dimensional hydrodynamic mathematical model is:

[0146] In the Cartesian coordinate system, ignoring the barotropic pressure, Reynolds stress and dispersion in the momentum equation, the two-dimensional shallow water equation based on the average water depth can be simply written as:

[0147]

[0148]

[0149]

[0150] wherein, is the water depth; and are the flow velocities in the and directions, respectively; , are source terms, and the expressions are:

[0151]

[0152]

[0153] where, P is the water surface atmospheric pressure; Z is the bed elevation; and F is the wind load force, expressed as:

[0154]

[0155]

[0156] where, p is the air density; and V is the wind speed at 10 m above the water surface; Cd is the drag coefficient. and Cf is the Coriolis force, expressed as:

[0157]

[0158]

[0159] where, Cf is the Coriolis coefficient, w is the angular velocity of the earth, φ is the latitude.

[0160] R is the bottom bed resistance, expressed as:

[0161]

[0162]

[0163] where, ks is the roughness.

[0164] Equations (1), (2), and (3) can be written in vector form as:

[0165]

[0166] where, , and are the partial derivatives with respect to time, space and directions, respectively,

[0167] ​​​

[0168]

[0169] The specific steps of the embodiment are as follows:

[0170] Step 1: Collect the observation data of hydrology, underwater topography, fixed section and local tributary estuary section hydrodynamic conditions in the BHT reservoir area from 2021 to 2024, and construct a one-dimensional river network hydrodynamic mathematical model of the long river section in the reservoir area. Figure 1 The length of the BHT reservoir area is about 182 km. The calibration and verification calculation work of the model is completed.

[0171] Step 2: For the constant flow process that may exist in the BHT reservoir area, the downstream hydrodynamic process of the peak shaving power station under different working conditions is simulated. In this example, the constant flow condition is selected as: the discharge of the WDD hub in the upper reaches is constant at 8000 m 3 / s, and the water level on the lower boundary of the BHT dam is constant at 770 m. Through the numerical simulation of the constant flow condition of the downstream river section of the WDD hub of the peak shaving power station in the one-dimensional hydrodynamic mathematical model of the long river section in the BHT reservoir area established in step 1, the corresponding changes of water level and average flow velocity along the section are obtained. Figure 2 and Figure 3 ).

[0172] Step 3: For the non-constant flow process that may exist in the BHT reservoir area, the downstream hydrodynamic process of the peak shaving power station under different working conditions is simulated. In this example, the non-constant flow condition is selected as: the discharge of the WDD hub in the upper reaches gradually increases from 2000 m 3 / s to 4000 m 3 / s, with an increase of 1.67 m 3 / s, taking 20 minutes, and the water level on the lower boundary of the BHT dam is constant at 760 m. Through the numerical simulation of the non-constant flow condition of the downstream river section in the one-dimensional hydrodynamic mathematical model of the long river section in the BHT reservoir area established in step 1, the corresponding changes of water level and average flow velocity along the section are obtained. Figure 4 and Figure 5 ).

[0173] Step 4: The tail river section of the BHT reservoir area is sensitive to the peak shaving discharge of the WDD hydropower station. The minimum discharge of a certain control hydrological station in this water area is 972 m 3 / s, and the corresponding water level is 792.97 m. According to the “Navigation Standard of Inland Rivers”, the design minimum navigation water level downstream of the hub building is the water level corresponding to the instantaneous minimum discharge of the hub. Therefore, the above 792.97 m can be used as the minimum navigation water level of the BHT reservoir area since the data. According to the data, the maximum navigation water level of the BHT reservoir area is 825.00 m. Therefore, the design navigation water level range of the downstream river section of the WDD hub is 792.97 m~825.00 m.

[0174] Step 5: According to the calculation result of step 2, under the water flow boundary condition, the BHT reservoir area meets the design navigation water level in the range of 136.06 km to 160.51 km from the dam, with a river length of about 24.45 km, accounting for about 14.29% of the BHT reservoir area.

[0175] Step 6: According to the calculation result of step 3, under the water flow condition before peak regulation, the BHT reservoir area meets the design navigation water level in the range of 137.68 km to 171.12 km from the dam, with a river length of about 33.44 km, accounting for about 19.54% of the BHT reservoir area.

[0176] Step 7: The BHT reservoir tail about 30 km river section is a variable backwater area. During the WDD hub peak regulation process, a two-dimensional hydrodynamic mathematical model of the BHT reservoir tail river section is constructed. Based on the one-dimensional hydrodynamic mathematical model of the BHT reservoir area constructed in step 3, the two-dimensional hydrodynamic mathematical model provides the water flow boundary condition process, simulates and calculates the two-dimensional hydrodynamic process of the BHT reservoir tail river section. The flow trajectory of the BHT reservoir tail 30 km river section is drawn, and three typical backwater areas are identified. Among them, the area ratio of the flow speed exceeding 3 m / s in the A backwater area is about 20%, the area ratio of the flow speed exceeding 3 m / s in the B backwater area is about 20%, and the area ratio of the flow speed exceeding 3 m / s in the C backwater area is about 20%.

[0177] The embodiment of the present application provides a non-safety navigation water area identification system downstream of a peak regulation power station, comprising a memory and a processor, wherein the memory comprises a program of a non-safety navigation water area identification method downstream of a peak regulation power station, and the program of the non-safety navigation water area identification method downstream of the peak regulation power station is executed by the processor to realize the steps of the non-safety navigation water area identification method downstream of the peak regulation power station.

[0178] The embodiment of the present application provides a computer readable storage medium, which stores a program code, and the program code is executed by a processor to realize the steps of the non-safety navigation water area identification method downstream of the peak regulation power station.

[0179] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0180] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof.

[0181] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof.

[0182] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof. Figure 1 one or more flowcharts and / or blocks in the flowcharts and / or combination thereof.

[0183] In one typical configuration, the computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0184] The memory can include non-persistent memory and / or volatile memory, such as a random access memory (RAM) including a cache area for the temporary storage of data. The memory can also include non-volatile memory, such as read only memory (ROM) for storing structural information and / or instruction code to implement the functions of the computing device. The memory can additionally or alternatively include mass storage for persistent storage of information and instructions.

[0185] Computer-readable media includes permanent and non-permanent, movable and non-movable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device. According to the definition herein, computer-readable media does not include transitory media such as modulated data signals and carriers.

[0186] The above only describes the embodiments of the present application and is not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for identifying non-navigable water areas downstream of a peak-shaving power station, characterized in that, Includes the following steps: Step 1. Establish a one- and two-dimensional coupled hydrodynamic mathematical model of the downstream river channel of the peak-shaving power station; Step 2. Determine the proposed conditions and the combination of water flow boundary conditions for a typical peak-shaving process downstream of the hydropower station; Step 3. Simulate and calculate the hydrodynamic conditions along the downstream of the power station under different peak-shaving processes; Step 4. Calculate the unsafe navigation indicators downstream of the peak-shaving power station; Step 5. Identify unsafe navigable waters downstream of peak-shaving power plants.

2. The method for identifying non-navigable water area downstream of a peak shaving power station according to claim 1, wherein, Step 1, establishing a one- and two-dimensional coupled hydrodynamic mathematical model of the downstream channel of the peak-shaving power station, includes the following steps: Step 11. Collect fixed section and underwater topographic observation data of the downstream river section and surrounding area of ​​the peak-shaving power station, and use the actual discharge flow process of the power station and the hydrological data of the main and tributary control stations as the data basis for the one- and two-dimensional coupled hydrodynamic mathematical models. Step 12. Divide the downstream study section of the peak-shaving power station into a series of computational grid cells along the length direction. The grid division should be determined according to the characteristics of the river section and the simulation accuracy requirements. Interpolate the underwater topographic data into the divided grid cells accordingly to form a model computational grid with nested topographic data. Step 13. Based on the data from Step 11 and the model mesh from Step 12, construct a one-dimensional hydrodynamic mathematical model of the downstream river section of the peak-shaving power station. The model is characterized by the following basic equations: Water flow continuity equation: , Water flow momentum equation: , Branch point water quantity continuity equation: , Branch point momentum continuity equation: , In the above equations, the physical meaning and unit of each symbol are as follows: x is the flow; Q is the flow rate; z is the water level; q is the interval inflow; u is the branch flow velocity; U is the main flow velocity; B is the river width; t is the time; A is the cross-sectional area of water; R is the hydraulic radius; n is the roughness coefficient; β is the momentum correction coefficient; M is the number of branch points in the river network, L(m) is the number of river sections connected to the branch point m, Z m,l is the water level at the end of the lth river section connected to the branch point m; Q m,l is the flow into or out of the branch point m of the lth river section connected to the branch point m, and the superscript n+1 indicates the calculation period. Based on the calculation results of the one-dimensional hydrodynamic mathematical model of the downstream river section of the constructed peak-shaving power station, flow boundary conditions are provided for the two-dimensional hydrodynamic mathematical model. The two-dimensional hydrodynamic mathematical model is characterized by the following basic equations: In Cartesian coordinates, the two-dimensional shallow water equation based on water depth averaging is simplified as follows: ， ， ， wherein is the water depth; and are respectively and the flow velocity in the direction of , is the source term; Step 14. Based on the collected hydrological data from the downstream river sections of the peak-shaving power station, calibrate the hydrodynamic parameters of the established one-dimensional and two-dimensional hydrodynamic mathematical models of the downstream river section of the peak-shaving power station, and verify the simulation results.

3. The method for identifying non-navigable water area downstream of a peak shaving power station according to claim 1, wherein, Step 2, which determines the proposed conditions and the combination of water flow boundary conditions for a typical peak-shaving process downstream of the hydropower station, includes the following steps: Step 21. Collect historical water level and flow data of typical control hydrological stations in the downstream section near the dam of the peak-shaving power station, and divide the flow level range according to the historical peak-shaving discharge flow process of the peak-shaving power station; Step 22. Based on the flow levels divided in Step 21, calculate the frequency of each flow level in the annual discharge flow of the peak-shaving power station, and use all flow levels with a frequency exceeding 30% as the flow boundary conditions for numerical simulation. Step 23. Based on the water level and flow data collected in Step 21, draw the water level-flow relationship curve; based on the flow classification of the peak-shaving power station in Step 22, plot the corresponding water level-flow relationship curve to give the corresponding lower boundary water level process of the model, and form the corresponding upper boundary flow process and lower boundary water level process combination.

4. The method for identifying non-navigable water area downstream of a peak shaving power station according to claim 1, wherein, Step 3, which involves simulating the downstream hydrodynamic conditions of the power station under different peak-shaving processes, includes the following steps: Step 31. Based on the actual discharge flow process of the peak-shaving power station over the years and the water level changes at the lower boundary observation section, sort the different peak-shaving flows and select the water flow condition combinations with high frequency of occurrence as typical peak-shaving water flow conditions, which will form the basis for subsequent numerical simulation calculation schemes. Step 32. Based on the established one-dimensional and two-dimensional coupled hydrodynamic mathematical model of the downstream river section of the peak-shaving power station, numerical simulation is performed on the typical peak-shaving flow conditions in Step 31, and the results of the changes in hydrodynamic elements such as the water level change along the route, the water surface gradient along the route, and the average flow velocity along the route are compiled. Step 33. Calculate the two-dimensional flow process downstream of the power station under typical peak flow conditions, plot the streamlines along the way, and identify the water area downstream of the peak power station where backwater phenomenon exists, and identify the radius and area of the backwater area, respectively and .

5. The method for identifying non-navigable water area downstream of a peak shaving power station according to claim 1, wherein, Step 4, which involves calculating the unsafe navigation indicators downstream of the peak-shaving power station, includes the following steps: Step 41. Organize the discharge flow data of the peak shaving power station for years to get the instantaneous minimum discharge flow for years , the corresponding water level is , according to the content of inland navigation standard, the design maximum navigation water level is ; for the design navigation water level range of the peak shaving power station is ; Step 42. Calculate the average velocity change process along the cross-section downstream of the power station under typical peak-shaving flow conditions. Based on the inland waterway navigation standards, select 3 m / s as the velocity identification threshold for unsafe water areas, which is: when When, then identify The cross-section is a non-safe navigable waterway; when When, then identify The cross-section is a suitable navigable waterway; Step 43. Based on the identified return water area radius and area Further identify the proportion of water area with a flow velocity exceeding 3 m / s within the backwater area. , This refers to the unsafe navigation area within the downstream backwater area of ​​the peak-shaving power station.

6. The method for identifying unsafe navigable waters downstream of a peak-shaving power station as described in claim 1, characterized in that, Step 5, identifying unsafe navigable waters downstream of the peak-shaving power station, includes the following steps: Step 51. When the peak shaving processes are respectively ( , When ), the corresponding criterion for determining the design navigation water level is: when hour, The cross-section is within the suitable navigable water level range; when or hour, The cross-section does not meet the suitable navigable water level range; Step 52. Under the condition that the water level meets navigation requirements, further determine the safe navigable water area based on the water flow velocity. When, then identify The cross-section is a safe navigable waterway; Step 53. Under the conditions of water level and current velocity for navigation, further based on the conditions of flow pattern for navigation, if the current velocity in the backwater area identified by the flow trace exceeds 3 m / s, it is judged as an unsafe navigation area, and the corresponding percentage of the unsafe navigation area in the backwater area is given. ; Step 54. Provide details for each peak-shaving process ( , The scope of unsafe navigation waters and their proportion in the downstream waters of peak-shaving power plants.

7. A system for identifying unsafe navigable waters downstream of a peak-shaving power station, characterized in that, The system includes a memory and a processor. The memory contains a program for identifying unsafe navigable waters downstream of a peak-shaving power station. When the program for identifying unsafe navigable waters downstream of a peak-shaving power station is executed by the processor, it performs the following steps: Step 1. Establish a one- and two-dimensional coupled hydrodynamic mathematical model of the downstream river channel of the peak-shaving power station; Step 2. Determine the proposed conditions and the combination of water flow boundary conditions for a typical peak-shaving process downstream of the hydropower station; Step 3. Simulate and calculate the hydrodynamic conditions along the downstream of the power station under different peak-shaving processes; Step 4. Calculate the unsafe navigation indicators downstream of the peak-shaving power station; Step 5. Identify unsafe navigable waters downstream of peak-shaving power plants.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores program code, which, when executed by a processor, implements the steps of the method for identifying unsafe navigable waters downstream of a peak-shaving power station as described in any one of claims 1 to 6.

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