CN111291459B - Method and system for determining silt flux of pump station approach channel and forebay - Google Patents
Method and system for determining silt flux of pump station approach channel and forebay Download PDFInfo
- Publication number
- CN111291459B CN111291459B CN201811391256.4A CN201811391256A CN111291459B CN 111291459 B CN111291459 B CN 111291459B CN 201811391256 A CN201811391256 A CN 201811391256A CN 111291459 B CN111291459 B CN 111291459B
- Authority
- CN
- China
- Prior art keywords
- silt
- flow
- sediment
- boundary layer
- flow velocity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
- G06F17/11—Complex mathematical operations for solving equations, e.g. nonlinear equations, general mathematical optimization problems
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- General Physics & Mathematics (AREA)
- Pure & Applied Mathematics (AREA)
- Mathematical Optimization (AREA)
- Mathematical Analysis (AREA)
- Computational Mathematics (AREA)
- Data Mining & Analysis (AREA)
- Theoretical Computer Science (AREA)
- Operations Research (AREA)
- Algebra (AREA)
- Databases & Information Systems (AREA)
- Software Systems (AREA)
- General Engineering & Computer Science (AREA)
- Barrages (AREA)
Abstract
The embodiment of the invention provides a method for determining silt flux of a pump station approach channel and a forebay, wherein the method comprises the following steps: obtaining the Sherz number, the sedimentation velocity of the sediment and the ratio of the sedimentation time and the flow period of the sediment in the sediment transport layer, and obtaining the phase drift of the sediment to the flow velocity and the phase residue of the sediment; and (3) taking the flow velocity of the outer boundary layer as a boundary condition, obtaining the depth of the sand-containing moving bed surface eroded by the water flow, the thickness of the boundary layer of the reciprocating flow and a boundary layer flow velocity lead function according to the grain diameter of the sediment, the flow period, the Siertz number, the sediment settling velocity, the phase drift of the sediment to the flow velocity and the phase residue of the sediment, and further determining the sediment flux. The design calculation is carried out through the determined related phase difference, the dynamic bed surface and the boundary layer thickness parameters, the time response required by the instantaneous sediment flux relative to hydrodynamic conditions in the reciprocating flow process can be reflected, the change of the dynamic bed surface and the dynamic bed surface effect are reflected, and the underestimation of the half-period average sediment flux is avoided.
Description
Technical Field
The embodiment of the invention relates to the technical field of hydraulic engineering, in particular to a method and a system for determining silt flux of a pump station approach channel and a forebay.
Background
The silt flux is the product of silt concentration and speed, represents the amount of silt passing through a unit section in unit time, and is dynamically changed in the reciprocating flow of the pump station approach and the front pool silt-containing bed surface.
Silt flux widely used in engineering is deduced based on a constant flow theory, changes of a movable bed surface are not considered, and asymmetry and phase difference effects of a boundary layer are not included. This leads to the disadvantages: the change of the moving bed surface and the moving bed surface effect cannot be reflected, the time response required by the sediment flux relative to hydrodynamic conditions cannot be reflected, the negative net flow speed and net flux caused by asymmetry of a boundary layer and large phase difference cannot be reflected, and the underestimation of the average sediment flux in a half period can be caused.
How to determine the instantaneous sediment flux including the change of the bed surface, the asymmetry of the boundary layer and the phase difference is an important basis for determining the net sediment transport amount of the sediment-bearing bed surface under the condition of reciprocating flow and is also a basis for judging the sediment entering a pump of a pump station and the abrasion condition of the pump. However, until now, there has not been any reference achievement and method for giving out the silt flux of the sand-containing moving bed surface under the condition of reciprocating flow of the pump station approach channel and the forebay, and therefore, the invention continues to provide a method for determining the silt flux of the pump station approach channel and the forebay.
Disclosure of Invention
Embodiments of the present invention provide a method and system for determining silt flux in a pump station approach channel and forebay that overcomes, or at least partially solves, the above-mentioned problems.
In a first aspect, an embodiment of the present invention provides a method for determining silt flux in an approach channel and a forebay of a pump station, including:
obtaining the flow velocity of the outer boundary layer of the pump station approach channel and the front pool water body, the density ratio of silt and water, the particle size of silt and the flow period;
according to the flow velocity of the outer boundary layer, the density ratio of the silt to the water, the particle size of the silt and the flow period, the Siertz number, the sedimentation velocity of the silt and the ratio of the sedimentation time of the silt in the sand conveying layer to the flow period are obtained, and the phase drift of the silt to the flow velocity and the phase residue of the silt are obtained;
and taking the flow velocity of the outer boundary layer as a boundary condition, and obtaining the depth of the sand-containing moving bed eroded by water flow, the thickness of the boundary layer of the reciprocating flow and the advanced function of the flow velocity of the boundary layer according to the particle size of the sediment, the flow period, the Siertz number, the sedimentation velocity of the sediment, the phase drift of the sediment to the flow velocity and the phase residue of the sediment, so as to determine the flux of the sediment.
In another aspect, an embodiment of the present invention provides a system for determining silt flux in an approach channel and a forebay of a pump station, including:
the first module is used for acquiring the flow velocity of the outer boundary layer of the pump station approach channel and the front pool water body, the density ratio of silt to water, the particle size of the silt and the flow period;
the second module is used for obtaining the Siertz number, the sediment settling velocity and the ratio of the settling time of the sediment in the sediment transport layer to the flow period according to the flow velocity of the outer boundary layer, the density ratio of the sediment to the water, the grain size of the sediment and the flow period, and obtaining the phase drift of the sediment to the flow velocity and the phase residue of the sediment;
and the third module is used for acquiring the depth of erosion of the sand-containing moving bed surface by water flow, the thickness of a boundary layer of the reciprocating flow and a boundary layer flow velocity lead function by taking the flow velocity of the outer boundary layer as a boundary condition according to the particle size of the sediment, the flow period, the Siertz number, the sedimentation velocity of the sediment, the phase drift of the sediment to the flow velocity and the phase residue of the sediment, and further determining the sediment flux.
In a third aspect, an embodiment of the present invention provides a system including a processor, a communication interface, a memory, and a bus, where the processor and the communication interface complete mutual communication through the bus, and the processor may call a logic instruction in the memory to execute the method for determining a silt flux of a pump station approach channel and a forebay provided in the first aspect.
In a fourth aspect, an embodiment of the present invention provides a non-transitory computer-readable storage medium, which stores computer instructions that cause a computer to execute the method for determining the silt flux of a pump station approach channel and a front pool provided in the first aspect.
According to the method and the system for determining the silt flux of the pump station approach channel and the forebay, the design calculation is carried out through the determined related phase difference, the movable bed surface and the boundary layer thickness parameters, the time response required by the instantaneous silt flux in the reciprocating flow process relative to hydrodynamic conditions can be reflected, the change of the movable bed surface and the movable bed surface effect are reflected, and the underestimation of the average silt flux in a half-period is avoided.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
Fig. 1 is a flowchart of a method for determining silt flux in a pump station approach and a forebay according to an embodiment of the present invention;
FIG. 2 is a graph of asymmetric reciprocating flow velocity and boundary layer thickness employed in an example of an embodiment of the present invention;
FIG. 3 is a graph of the instantaneous sediment flux for an asymmetric reciprocating flow bed surface as determined in an example embodiment of the present invention;
FIG. 4 is a graph showing the instantaneous sediment flux of an asymmetric reciprocating flow bed surface obtained by removing the phase difference effect in an embodiment of the present invention;
FIG. 5 is a graph of net flow rate and silt flux determined in an example of an embodiment of the present invention, where D is 0.1 mm;
FIG. 6 is a graph of net flow rate and silt flux determined in an example of an embodiment of the present invention, where D is 0.25 mm;
fig. 7 is a system for determining silt flux in a station approach and a forebay according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments, but not all embodiments, of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a flowchart of a method for determining silt flux in a pump station approach and a forebay according to an embodiment of the present invention, including:
s101, acquiring the flow velocity of the outer boundary layer of the water body of a pump station approach channel and a forebay, the density ratio of silt to water, the particle size of silt and the flow period;
s102, obtaining a Sherz number, a sediment settling velocity, a settling time of the sediment in a sediment transport layer and a flow period ratio according to the flow velocity of the outer boundary layer, the density ratio of the sediment to water, the grain size of the sediment and the flow period, and obtaining phase drift of the sediment to the flow velocity and phase residue of the sediment;
and S103, with the flow velocity of the outer boundary layer as a boundary condition, obtaining the depth of the sand-containing moving bed eroded by water flow, the thickness of the boundary layer of the reciprocating flow and a leading function of the flow velocity of the boundary layer according to the particle size of the sediment, the flow period, the Siertz number, the sedimentation velocity of the sediment, the phase drift of the sediment to the flow velocity and the phase residue of the sediment, and further determining the flux of the sediment.
According to the method for determining the silt flux of the pump station approach channel and the forebay, the determined related phase difference, the dynamic bed surface and the boundary layer thickness parameters are used for design calculation, so that the time response required by the instantaneous silt flux relative to hydrodynamic conditions in the reciprocating flow process can be reflected, the change of the dynamic bed surface and the dynamic bed surface effect are reflected, and the underestimation of the average silt flux of a half-period is avoided.
In the above embodiment, the acquiring of the flow velocity of the outer boundary layer of the pump station approach and the forebay water body specifically includes:
measuring the flow velocity of the outer boundary layer flowing back and forth, and expanding the flow velocity of the outer boundary layer in series to obtain the flow velocity U (t) of the outer boundary layer in a flow period:
wherein t represents time; k represents the order of the harmonic; n represents the order of harmonics; wkRepresents the amplitude of the k-th harmonic; omega is the frequency of harmonic wave, the value is 2 pi/T, and T is the flowing period; phi is akRepresents the lag of the k order harmonic; t is t0A parameter indicating that U (0) is 0. Since U (t) has been measured, N, Wk、ω、t0、φkAre all known values.
Specifically, the embodiment of the present invention is described by way of an example, assuming that the water body is under known conditions: a standard atmospheric pressure, a water temperature of 20 ℃ and a maximum outer boundary flow velocity Um1.2m/s, flow period T5 s, silt particle size D1.0X 10-4m, density ratio of silt to water s is 2.65, gravity acceleration g is 9.8m/s2Coefficient of kinetic viscosity of water (v) 1.0X 10-6m2And s. The asymmetric 2-step Stokes reciprocating flow velocity process is adopted for expansion as follows:
U(t)＝0.96cos[2π(t/T-0.214)]+0.24cos[4π(t/T-0.214)]，
as shown in fig. 2, N is 2, W corresponds to formula (1)k＝0.96×0.25k-1m/s、ω＝0.4πs-1、t0＝-0.18s、φk＝-0.5(k-1)π。
In the above embodiment, the obtaining the siertz number Θ specifically includes:
substituting the measured flow velocity of the outer boundary layer, the density ratio of the silt to the water, the particle size of the silt and the flow period into the following first equation group:
solving the first equation set to obtain the Sherz number;
wherein, UmIs the maximum value of U, s representsDensity ratio of silt to water, D represents silt particle size, T represents flow period, thetamIs the maximum value of theta, f represents the friction factor of the couch top with the sand, and g represents the gravitational acceleration.
Specifically, continuing with the above example, calculating the siertz number Θ and the friction factor f with the sand-moving couch top according to the first equation group specifically includes:
(1) first assume thatm<1, f is 6.6 × 10 from the following equation of the first equation set-3(ii) a Substituting the formula above the first equation group to obtain thetam2.94 > 1. If the situation is not true, performing the step (2);
(2) according to the formula thetamGreater than 1, add UmSubstituting the formula above the formula first equation set and the formula above the first equation set into the following formula of the first equation set to obtain:
from formula (2) to yield f ═ 1.0X 10-2Substituting into the formula above the first equation group to obtain thetam4.45, and
Θ(t)＝3.09U2 (3)
in the above embodiment, the obtaining of the settling velocity of the sediment and the ratio of the settling time of the sediment in the sediment transport layer to the flow period specifically includes:
substituting the flow velocity of the outer boundary layer, the density ratio of the silt to the water, the particle size of the silt, the flow period and the Sherz number into the following second equation set:
solving the second equation set to obtain the settling velocity of the sediment and the ratio of the settling time of the sediment in the sediment transport layer to the flow period;
wherein, UmIs the maximum value of U, s represents the density ratio of silt to waterThe value D represents the silt particle size, T represents the flow period, thetamIs the maximum value of theta, g represents the gravity acceleration, w represents the sediment velocity of the sediment, psi represents the ratio of the sediment time and the flow period of the sediment in the sediment transport layer, v represents the kinematic viscosity coefficient of water, theta represents the Sherz number, and U represents the flow velocity of the outer boundary layer.
Specifically, continuing with the above example, calculating the sediment settling velocity w and the ratio Ψ of the sediment settling time in the sand transporting layer to the flow period according to the second equation system specifically includes:
from the following equation of the second equation set, w is 8.4 × 10-3And m/s is substituted into the formula in the second equation set to obtain psi as 1.1.
In the above embodiment, the obtaining of the phase shift of the flow velocity by the sediment and the phase residue of the sediment specifically includes:
substituting the ratio of the settling time of the sediment in the sediment transport layer to the flow period into the following third equation group:
solving the third equation group to obtain the phase drift of the silt to the flow velocity and the phase residue of the silt;
wherein psi represents the ratio of the settling time of silt in the sediment transport layer to the flow period, psi represents the phase shift of silt to the flow velocity, alpha represents the residue of silt phase, and T represents the flow period.
Specifically, continuing with the above example, calculating the phase shift ψ of silt to the flow velocity and the residual α of silt phase according to a third equation includes:
derived ψ from the above equation of the third equation group of 8.7 × 10-1s, α is obtained from the following formula of the third equation 8.3 × 10-1。
In the above embodiment, the acquiring the depth of the sand-containing moving bed eroded by the water flow and the thickness of the boundary layer of the reciprocating flow specifically includes:
substituting the sediment particle size, the flow period, the Siertz number, the sediment settling velocity, the phase drift of the sediment to the flow velocity and the phase residue of the sediment into the following fourth process group:
solving the fourth process group to obtain the depth of the sand-containing moving bed surface eroded by the water flow and the thickness of the boundary layer of the reciprocating flow;
wherein, UmIs the maximum value of U, D represents the silt particle size, T represents the flow period, thetamIs the maximum value of theta, w represents the silt settling velocity, psi represents the phase shift of silt to the flow velocity, alpha represents the residue of silt phase, thetacrRepresenting the critical Sherz number, Δ representing the depth of erosion of the sand-containing moving bed by the water flow, δBThe thickness of the boundary layer of the reciprocating flow is represented, t represents time, theta represents the Sherz number, and U represents the flow velocity of the outer boundary layer.
In particular, continuing with the above example, the erosion depth Δ and the boundary layer thickness δ are calculated according to a fourth set of aspectsBThe method specifically comprises the following steps:
substituting the parameters and sediment into a fourth equation set to obtain the phase drift psi of the flow velocity and the residual alpha of the sediment phase:
Δ(t+0.87)＝(30.54+4.26U2)×10-4 (4)
δB(t)＝0.022×[max(1,3.09U2)]0.18 (5)
in the above embodiment, the silt flux is:
wherein q isBRepresenting the instantaneous silt flux, y being the vertical coordinate, t representing time, F being the boundary layer flow velocity advance function, SmThe maximum volume concentration of silt is generally 0.6.
Specifically, before calculating silt flux, the boundary layer flow velocity lead function needs to be calculated:
wherein beta is the phase advance of the moving bed surface flow velocity and the shear stress relative to the outer boundary layer flow velocity, and the value of the invention can be taken as 0.32 aiming at the turbulent flow.
Continuing with the example in the above embodiment, SmSubstituting the expression of the silt flux into the expression of the formula (6) and the expression of the formula (0.6), and obtaining the instantaneous silt flux of the silt volumeter under the asymmetric reciprocating flow condition of the embodiment of the invention by taking the expression of the silt flux of the formula (0.32):
converting U (t), N2, Wk＝0.96×0.25k-1m/s、ω＝0.4πs-1、t0＝-0.18s、φk-0.5(k-1) pi, Δ retardation of 0.87s for formula (4) and δ for formula (5)BSubstituting formula (7) to obtain the instantaneous sediment flux distribution shown in figure 3. For comparison, the instantaneous silt flux profile for dephasing is shown in FIG. 4.
Net silt flux is<qB>＝<UBSB>See FIG. 5, can be decomposed into<qB>＝qBc+qBw. Wherein, the sharp brackets represent the periodic mean; q. q.sBc＝<UB><SB>Is the net silt flux from the net flow velocity; q. q.sBw＝<UB′SB′>Is the net silt flux due to fluctuating flow velocity; u shapeB′＝UB-<UB>；SB′＝SB-<SB>. Increasing the particle diameter until D is 0.25mm, repeating the above calculation steps, and reducing the phase difference parameter until psi is 1.5 × 10-1、ψ＝1.2×10-1s、α＝2.6×10-1Corresponding to the net flow rate and silt flux of figure 6.
The embodiment of the invention adopts the method, as shown in figures 2-6, so that the instantaneous sediment flux has the following 3 advantages brought by considering the action of the change of the movable bed surface, the asymmetry of the boundary layer and the phase difference:
the change of the movable bed surface and the movable bed surface effect can be reflected.
The silt flux is established on the moving bed surface with the erosion depth delta, and the embodiment of the invention embodies that the moving bed surface changes periodically along with the water flow, so that the classical moving bed surface effect under the action of weak phase difference can be embodied, as shown in figure 6. Because the flow strength of the positive half period (T/T is 0.00-0.42) is greater than that of the negative half period (T/T is 0.42-1.00), and under the condition that D is 0.25mm under the action of weak phase difference, the sediment at the bottom of the sand transportation layer can only move at the positive high-flow-speed stage, and thus the net flow speed and the net sediment flux at the bottom of the sand transportation layer in the graph 6 are both positive.
And (II) the underestimation of the average silt flux in the half-period can be avoided.
When strong phase difference acts, because of larger phase residue, the silt lifted at the flow peak stage (T/T is about 0.21) is carried into the rest stage to enhance the silt flux, and the silt flux at the flow turning time T/T is 0.00 and 0.43 is not 0, as shown in fig. 3. After the phase difference effect is removed in fig. 4, the silt flux at the flow turning time T/T is 0.00 and 0.43 is unreasonably reduced to 0; the silt flux at the rest of the time is rapidly reduced, which can cause underestimation of the average silt flux in a positive half period (T/T is 0.00-0.42) or a negative half period (T/T is 0.42-1.00).
And (III) the negative net flow speed and the net flux caused by asymmetry and large phase difference of the boundary layer can be reflected.
The 2-step Stokes flow is a typical asymmetric reciprocating flow, the boundary layer thickness of the solid line in fig. 2 is asymmetric, the boundary layer thickness of the negative half period (T/T is 0.42-1.00) is thinner than that of the positive half period (T/T is 0.00-0.42), and the boundary layer flow velocity of the relatively strong negative flow corresponds to the boundary layer flow velocity of the relatively strong negative flow. The large phase difference makes the surface of the sand layer (y ═ - Δ) almost constant, without moving bed surface effect, and thus creates a negative boundary layer net flow velocity, as shown in fig. 5. The large phase difference causes the change of the silt concentration to be small, namely the concentration S of the fluctuation part of the siltB' and net silt flux q brought aboutBw＝<UB′SB′>Tending to 0. In this way,<qB>＝qBc+qBw＝qBc＝<UB><SB>i.e. the total net silt flux equals the negative net silt flux due to the net flow velocity, as shown in figure 5.
Wherein, in FIG. 2, T/T is dimensionless time; U/UmIs a dimensionless outer boundary layer flow velocity; deltaB/δBmIs the dimensionless boundary layer thickness. In FIG. 3, qBSilt flux by volume; T/T is dimensionless time; y is the vertical coordinate, where the initial couch top is at 0. In FIG. 4, qBSilt flux by volume; T/T is dimensionless time; y is the vertical coordinate, where the initial couch top is at 0. In fig. 5, y is a vertical coordinate, where y is 0, the initial couch top;<qB>is the net silt flux; q. q.sBcIs the net silt flux from the net flow velocity; q. q.sBwIs the net silt flux brought by the fluctuating portion; the brackets indicate the periodic mean; this figure corresponds to a silt particle size of 0.1 mm. In fig. 6, y is a vertical coordinate, where y is 0, the initial couch top;<qB>is the net silt flux; q. q.sBcIs the net silt flux from the net flow velocity; q. q.sBwIs the net silt flux brought by the fluctuating portion; the brackets indicate the periodic mean; this figure corresponds to a silt particle size of 0.25 mm.
Fig. 7 is a block diagram of a structure of a system for determining silt flux in a station approach and a front pool according to an embodiment of the present invention, as shown in fig. 7, including: a first module 701, a second module 702, and a third module 703. Wherein:
the first module 701 is used for acquiring the flow velocity of the outer boundary layer of the pump station approach and the front pool water body, the density ratio of silt to water, the silt particle size and the flow period. The second module 702 is configured to obtain the siertz number, the sedimentation velocity of the sediment, and the ratio of the sedimentation time of the sediment in the sediment transport layer to the flow period according to the outer boundary flow velocity, the density ratio of the sediment to water, the particle size of the sediment, and the flow period, and obtain the phase shift of the sediment to the flow velocity and the phase residue of the sediment. The third module 703 is configured to use the outer boundary flow velocity as a boundary condition, and obtain the depth of erosion of the sand-containing moving bed by the water flow, the thickness of the boundary layer of the reciprocating flow, and a leading function of the boundary layer flow velocity according to the sediment particle size, the flow period, the siertz number, the sediment settling velocity, the phase shift of the sediment to the flow velocity, and the phase residue of the sediment, so as to determine the sediment flux.
Specifically, the functions and operation flows of the modules in the embodiments of the present invention correspond to those in the embodiments of the method class one to one, and are not described herein again.
According to the system for determining the silt flux of the pump station approach channel and the forebay, the design calculation is carried out through the determined related phase difference, the movable bed surface and the boundary layer thickness parameters, the time response required by the instantaneous silt flux relative to hydrodynamic conditions in the reciprocating flow process can be reflected, the change of the movable bed surface and the effect of the movable bed surface are reflected, and the underestimation of the average silt flux of a half period is avoided.
Fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 8, the electronic device includes: a processor (processor)801, a communication Interface (Communications Interface)802, a memory (memory)803 and a bus 804, wherein the processor 801, the communication Interface 802 and the memory 803 complete communication with each other via the bus 804. The processor 801 may call logic instructions in the memory 803 to perform methods including, for example: obtaining the flow velocity of the outer boundary layer of the pump station approach channel and the front pool water body, the density ratio of silt and water, the particle size of silt and the flow period; according to the flow velocity of the outer boundary layer, the density ratio of the silt to the water, the particle size of the silt and the flow period, the Siertz number, the sedimentation velocity of the silt and the ratio of the sedimentation time of the silt in the sand conveying layer to the flow period are obtained, and the phase drift of the silt to the flow velocity and the phase residue of the silt are obtained; and taking the flow velocity of the outer boundary layer as a boundary condition, and obtaining the depth of the sand-containing moving bed eroded by water flow, the thickness of the boundary layer of the reciprocating flow and the advanced function of the flow velocity of the boundary layer according to the particle size of the sediment, the flow period, the Siertz number, the sedimentation velocity of the sediment, the phase drift of the sediment to the flow velocity and the phase residue of the sediment, so as to determine the flux of the sediment.
The logic instructions in the memory 802 may be implemented in software functional units and stored in a computer readable storage medium when sold or used as a stand-alone product. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
Embodiments of the present invention provide a non-transitory computer-readable storage medium, which stores computer instructions, where the computer instructions cause the computer to perform the methods provided by the above method embodiments, for example, the methods include: obtaining the flow velocity of the outer boundary layer of the pump station approach channel and the front pool water body, the density ratio of silt and water, the particle size of silt and the flow period; according to the flow velocity of the outer boundary layer, the density ratio of the silt to the water, the particle size of the silt and the flow period, the Siertz number, the sedimentation velocity of the silt and the ratio of the sedimentation time of the silt in the sand conveying layer to the flow period are obtained, and the phase drift of the silt to the flow velocity and the phase residue of the silt are obtained; and taking the flow velocity of the outer boundary layer as a boundary condition, and obtaining the depth of the sand-containing moving bed surface eroded by water flow and the thickness of the boundary layer of the reciprocating flow according to the particle size of the sand, the flow period, the Sierpitz number, the sedimentation velocity of the sand, the phase drift of the flow velocity of the sand, the phase residue of the sand and the advance function of the flow velocity of the boundary layer, so as to determine the flux of the sand.
Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.
The above-described embodiments of the communication device and the like are merely illustrative, and units illustrated as separate components may or may not be physically separate, and components displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods of the various embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (7)
1. A method for determining silt flux of a pump station approach channel and a forebay is characterized by comprising the following steps:
obtaining the flow velocity of the outer boundary layer of the pump station approach channel and the front pool water body, the density ratio of silt and water, the particle size of silt and the flow period;
according to the flow velocity of the outer boundary layer, the density ratio of the silt to the water, the particle size of the silt and the flow period, the Siertz number, the sedimentation velocity of the silt and the ratio of the sedimentation time of the silt in the sand conveying layer to the flow period are obtained, and the phase drift of the silt to the flow velocity and the phase residue of the silt are obtained;
taking the flow velocity of the outer boundary layer as a boundary condition, and obtaining the depth of the sand-containing moving bed surface eroded by water flow, the thickness of a boundary layer of a reciprocating flow and a leading function of the flow velocity of the boundary layer according to the particle size of the sediment, the flow period, the Sierpiz number, the sedimentation velocity of the sediment, the phase drift of the sediment to the flow velocity and the phase residue of the sediment, so as to determine the flux of the sediment;
the outer boundary layer flow velocity of the pump station approach and the front pool water body is obtained, and the method specifically comprises the following steps:
measuring the flow velocity of the outer boundary layer flowing back and forth, and expanding the flow velocity of the outer boundary layer in series to obtain the flow velocity U (t) of the outer boundary layer in a flow period:
wherein t represents time, k represents the order of harmonics, N represents the order of harmonics, WkRepresenting the amplitude of the harmonic of order k, omega being the frequency of the harmonic and taking the value 2 pi/T, T being the flow period, phikLag representing the k harmonic, t0A parameter indicating that U (0) is 0;
the method for acquiring the depth of the sand-containing moving bed surface eroded by water flow and the thickness of the boundary layer of the reciprocating flow specifically comprises the following steps:
substituting the phase drift of the silt to the flow velocity and the phase residue of the silt into the following fourth process group:
solving the fourth process group to obtain the depth of the sand-containing moving bed surface eroded by the water flow and the thickness of the boundary layer of the reciprocating flow;
wherein U denotes the outer boundary layer flow velocity, UmIs the maximum value of U, D represents the sediment particle size, theta represents the Siertz number, thetamIs the maximum value of theta, w represents the silt settling velocity, psi represents the phase shift of silt to the flow velocity, alpha represents the residue of silt phase, thetacrRepresenting the critical Sherz number, Δ representing the depth of erosion of the sand-containing moving bed by the water flow, δBRepresenting the thickness of the reciprocating flow boundary layer;
the flow velocity advance function and the silt flux of the boundary layer are as follows:
wherein F is a boundary layer flow velocity advance function, beta is the phase advance of the moving bed surface flow velocity and the shear stress relative to the outer boundary layer flow velocity, beta takes a value of 0.32 aiming at the turbulent flow, and q is a valueBRepresenting the instantaneous silt flux, y being the vertical coordinate, SmIs the maximum volume concentration of silt.
2. The method according to claim 1, wherein the obtaining the Sherz number specifically comprises:
substituting the flow velocity of the outer boundary layer, the density ratio of the silt to the water, the particle size of the silt and the flow period into the following first equation group:
solving the first equation set to obtain the Sherz number;
wherein s represents the density ratio of silt to water, f represents the friction factor of the silt-containing moving bed surface, and g represents the gravity acceleration.
3. The method of claim 2, wherein the obtaining of the sediment settling velocity and the ratio of the sediment settling time to the flow period in the sediment transport layer specifically comprises:
substituting the flow velocity of the outer boundary layer, the density ratio of the silt to the water, the particle size of the silt, the flow period and the Sherz number into the following second equation set:
solving the second equation set to obtain the settling velocity of the sediment and the ratio of the settling time of the sediment in the sediment transport layer to the flow period;
wherein psi represents the ratio of the settling time of the sediment in the sediment transport layer to the flowing period, and v represents the kinetic viscosity coefficient of the water.
4. The method of claim 3, wherein the obtaining of the phase shift of silt to the flow velocity and the phase residue of silt specifically comprises:
substituting the ratio of the settling time of the sediment in the sediment transport layer to the flow period into the following third equation group:
and solving the third equation group to obtain the phase drift of the silt to the flow velocity and the phase residue of the silt.
5. The utility model provides a pump station approach and forebay silt flux's definite system which characterized in that includes:
the first module is used for acquiring the flow velocity of the outer boundary layer of the pump station approach channel and the front pool water body, the density ratio of silt to water, the particle size of the silt and the flow period;
the second module is used for obtaining the Siertz number, the sediment settling velocity and the ratio of the settling time of the sediment in the sediment transport layer to the flow period according to the flow velocity of the outer boundary layer, the density ratio of the sediment to the water, the grain size of the sediment and the flow period, and obtaining the phase drift of the sediment to the flow velocity and the phase residue of the sediment;
a third module, configured to obtain, by using the flow velocity of the outer boundary layer as a boundary condition, a depth of erosion of the sand-containing moving bed by the water flow, a thickness of a boundary layer of the reciprocating flow, and a leading function of a flow velocity of the boundary layer according to the particle size of the sediment, the flow period, the siertz number, the sedimentation velocity of the sediment, a phase shift of the sediment to the flow velocity, and a phase residue of the sediment, so as to determine a flux of the sediment;
the outer boundary layer flow velocity of the pump station approach and the front pool water body is obtained, and the method specifically comprises the following steps:
measuring the flow velocity of the outer boundary layer flowing back and forth, and expanding the flow velocity of the outer boundary layer in series to obtain the flow velocity U (t) of the outer boundary layer in a flow period:
wherein t represents time, k represents the order of harmonics, N represents the order number of harmonics, and WkRepresenting the amplitude of the harmonic of order k, omega being the frequency of the harmonic and taking the value 2 pi/T, T being the flow period, phikLag representing the k harmonic, t0A parameter indicating that U (0) is 0;
the method for acquiring the depth of the sand-containing moving bed surface eroded by water flow and the thickness of the boundary layer of the reciprocating flow specifically comprises the following steps:
substituting the phase drift of the silt to the flow velocity and the phase residue of the silt into the following fourth process group:
solving the fourth process group to obtain the depth of the sand-containing moving bed surface eroded by the water flow and the thickness of the boundary layer of the reciprocating flow;
wherein U denotes the outer boundary layer flow velocity, UmIs the maximum value of U, D represents the sediment particle size, theta represents the Siertz number, thetamIs the maximum value of theta, w represents the silt settling velocity, psi represents the phase shift of silt to the flow velocity, alpha represents the residue of silt phase, thetacrRepresenting the critical Sherz number, Δ representing the depth of erosion of the sand-containing moving bed by the water flow, δBRepresenting the thickness of the reciprocating flow boundary layer;
the flow velocity advance function and the silt flux of the boundary layer are as follows:
wherein F is a boundary layer flow velocity advance function, beta is the phase advance of the moving bed surface flow velocity and the shear stress relative to the outer boundary layer flow velocity, beta takes a value of 0.32 aiming at the turbulent flow, and q is a valueBRepresenting the instantaneous silt flux, y being the vertical coordinate, SmIs the maximum volume concentration of silt.
6. An electronic device, comprising a processor, a communication interface, a memory and a bus, wherein the processor, the communication interface and the memory communicate with each other via the bus, and the processor can call logic instructions in the memory to execute the method for determining the silt flux of the pump station approach channel and the forebay according to any one of claims 1 to 4.
7. A non-transitory computer readable storage medium storing computer instructions for causing a computer to perform the method of determining pump station approach and forebay silt flux of any of claims 1 to 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811391256.4A CN111291459B (en) | 2018-11-21 | 2018-11-21 | Method and system for determining silt flux of pump station approach channel and forebay |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811391256.4A CN111291459B (en) | 2018-11-21 | 2018-11-21 | Method and system for determining silt flux of pump station approach channel and forebay |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111291459A CN111291459A (en) | 2020-06-16 |
| CN111291459B true CN111291459B (en) | 2022-02-08 |
Family
ID=71029020
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811391256.4A Active CN111291459B (en) | 2018-11-21 | 2018-11-21 | Method and system for determining silt flux of pump station approach channel and forebay |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111291459B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6262942B1 (en) * | 1999-03-26 | 2001-07-17 | The United States Of America As Represented By The Secretary Of The Navy | Turbulence-resolving coherent acoustic sediment flux probe device and method for using |
| CN106320256A (en) * | 2016-08-22 | 2017-01-11 | 河海大学 | Method for determining flux of sediment passing through turbine of pumped storage power station for heavily silt-carrying rivers |
| CN106605158A (en) * | 2014-09-05 | 2017-04-26 | 雪佛龙美国公司 | Sediment transport simulation with parameterized templates for depth profiling |
| CN106709153A (en) * | 2016-11-29 | 2017-05-24 | 中国农业大学 | Method for determining blowing sand rate of forebay of pumping station |
| CN106777558A (en) * | 2016-11-29 | 2017-05-31 | 中国农业大学 | A kind of determination method of pumping plant approach channel and forebay water body silt reference concentration |
| CN106777557A (en) * | 2016-11-29 | 2017-05-31 | 中国农业大学 | A kind of determination method of pumping plant approach channel and forebay water body carrying rate |
| CN108256177A (en) * | 2017-12-28 | 2018-07-06 | 中国水利水电科学研究院 | A kind of parameter optimization method and system of river Water-sand model |
-
2018
- 2018-11-21 CN CN201811391256.4A patent/CN111291459B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6262942B1 (en) * | 1999-03-26 | 2001-07-17 | The United States Of America As Represented By The Secretary Of The Navy | Turbulence-resolving coherent acoustic sediment flux probe device and method for using |
| CN106605158A (en) * | 2014-09-05 | 2017-04-26 | 雪佛龙美国公司 | Sediment transport simulation with parameterized templates for depth profiling |
| CN106320256A (en) * | 2016-08-22 | 2017-01-11 | 河海大学 | Method for determining flux of sediment passing through turbine of pumped storage power station for heavily silt-carrying rivers |
| CN106709153A (en) * | 2016-11-29 | 2017-05-24 | 中国农业大学 | Method for determining blowing sand rate of forebay of pumping station |
| CN106777558A (en) * | 2016-11-29 | 2017-05-31 | 中国农业大学 | A kind of determination method of pumping plant approach channel and forebay water body silt reference concentration |
| CN106777557A (en) * | 2016-11-29 | 2017-05-31 | 中国农业大学 | A kind of determination method of pumping plant approach channel and forebay water body carrying rate |
| CN108256177A (en) * | 2017-12-28 | 2018-07-06 | 中国水利水电科学研究院 | A kind of parameter optimization method and system of river Water-sand model |
Non-Patent Citations (3)
| Title |
|---|
| Analyticalapproachforsheet flowtransportinpurely acceleration-skewed oscillatory flow;Xin Chen;《InternationalJournalofSedimentResearch》;20180509;234-242 * |
| Sediment flux based model of instantaneous sediment transport due to pure velocity-skewed oscillatory sheet flow with boundary layer stream;Xin Chen;《Coastal Engineering》;20180509;210-219 * |
| Sediment transport in pure acceleration-skewed oscillatory sheet flow;Xin Chen;《Journal of Hydrodynamics》;20181023;1045-1054 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111291459A (en) | 2020-06-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Moradi et al. | Effect of inlet configuration on wave resonance in the narrow gap of two fixed bodies in close proximity | |
| Gohil et al. | Numerical study of cavitation in Francis turbine of a small hydro power plant | |
| Yu et al. | Cavitation shedding dynamics around a hydrofoil simulated using a filter-based density corrected model | |
| CN110175377B (en) | Numerical forecasting method for hydrofoil cloud-shaped cavitation | |
| CN113947042B (en) | Three-dimensional numerical simulation method and system for fluid flushing submarine pipeline | |
| Scillitoe et al. | Evaluation of RANS and ZDES methods for the prediction of three-dimensional separation in axial flow compressors | |
| CN106320256B (en) | A kind of heavily silt-carrying river hydroenergy storage station crosses the definite method of machine silt flux | |
| Tao et al. | Optimization for Cavitation Inception Performance of Pump‐Turbine in Pump Mode Based on Genetic Algorithm | |
| Hillebrand et al. | 3D CFD modelling of velocities and sediment transport in the Iffezheim hydropower reservoir | |
| CN111259606B (en) | Method and device for determining flow velocity distribution of sand-containing moving bed surface of pump station approach and forebay | |
| CN111291459B (en) | Method and system for determining silt flux of pump station approach channel and forebay | |
| Kinnas et al. | Numerical modeling of a marine propeller undergoing surge and heave motion | |
| Qin et al. | A virtual single-phase natural cavitation model and its application to Cav2003 hydrofoil | |
| CN113947043A (en) | Method and system for monitoring vibration frequency of submarine pipeline based on CFD simulation | |
| CN111236132B (en) | Method and device for determining single-width sand conveying rate of pump station approach channel and front pool | |
| CN106709153B (en) | A kind of determination method of Forebay of Pumping Station sand rate | |
| Chivaee | Large eddy simulation of turbulent flows in wind energy | |
| CN111208274B (en) | Method and system for determining distribution of silt concentration of water bodies of pump station approach channel and forebay | |
| Taranov et al. | Influence of the laminar-turbulent transition on the accuracy of the propeller characteristics prediction in the model scale | |
| CN111324934A (en) | Method and device for determining total amount of suspended sand in pump station approach channel and forebay | |
| CN110188310B (en) | Cascade reservoir multi-flow-state composite sediment ejection prediction method and device | |
| CN110210139B (en) | Vortex-induced vibration amplitude prediction curve correction method aiming at Reynolds average method | |
| CN115309199B (en) | Method and system for controlling basic flow of downstream channel of junction based on channel scale | |
| Kim et al. | Long time computation of two-dimensional vortex sheet by point vortex method | |
| Corestein et al. | Modelling bedload transport for mixed flows in presence of a non-erodible bed layer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |