CN203603125U - Folding-type trash holding fence used for trash holding in pump station - Google Patents

Abstract

The utility model discloses a folding-type trash holding fence used for trash holding in a pump station, and belongs to the technical field of trash holding and trash cleaning in the pump station. The folding-type trash holding fence comprises planar fence bodies and is characterized in that the folding-type trash holding fence is formed by connecting and assembling the upper planar fence body and the lower planar fence body in a hinged mode, and the lower fence body is vertically or nearly vertically installed and placed; the upper fence body is installed and placed with a large inclination angle in the water flow direction, and it is guaranteed that floating objects can slide upwards along the fence face by means of water flow. The included angle between the upper planar fence body and the horizontal plane is beta, the beta is between 15 degrees to 45 degrees, and when the flow speed of water flow is small, the value of beta is small; when the flow speed of water flow is large, the value of beta is large so that it is guaranteed that the floating objects can slide upwards along the upper fence face under the action of water flow, and blocking to the fence face is reduced. Compared with a traditional planar trash holding fence, when the folding-type trash holding fence is adopted by the pump station for trash holding, the blocking depth of pollutants with the same size in front of the fence is smaller, the trash holding waterhead is small, the speed distribution of flow behind the fence is improved, more than 6 percent of operation cost of the pump station is saved, trash cleaning is convenient to perform, and trash cleaning cost is low.

Description

A kind ofly block dirty folding shape trashrack for pumping plant

Technical field

The utility model relates to a kind of trashrack, and especially large and medium-sized pumping plant and power station arrange the structure of trashrack in diversion channel or before water inlet flow channel.Belong to pumping plant dirt-blocking dirt-cleaning technical field.

Background technology

At present, China's electromechanical irrigation power recoverable amount reaches more than 8,000 ten thousand kW, wherein more than 5500 of big-and-middle-sized pumping plant.For guaranteeing water pump assembly safe operation, prevent that the dirt in river course from stopping up water pump or interrupting blade, pumping plant generally arranges trashrack in diversion channel or before water inlet flow channel, the incoming flow floating thing that interception comes with current.Traditional trashrack generally adopts plane trashrack, at right angle setting, or grid face becomes 15 ° with vertical plane.Pumping plant dirt is take pasture and water as main, and proportion is less than water body.Before grid, first pasture and water stop up top grid face, because trashrack grid face is in vertical or basic upright position, follow-up pasture and water are easy to stop up bottom grid face with current dive, grid face stops up when serious can form the larger dirty head loss of blocking, as blocking sewage potential difference, certain pumping plant exceedes 1.5m, another pumping plant maximum is blocked sewage potential difference and is reached 2.85m, efficiency of pumping station declines 20%～35%, and after grid, flow velocity is very disorderly, bottom velocity is large, and top flow velocity is little and have the appearance of backflow, simultaneously, also reduce to a certain extent pump assembly efficiency, pumping station operation expense increases.In addition, before planar shaped trashrack grid, dirt plug depth is large, and the hoisting depth of removing contamination is large, the comparatively difficulty of removing contamination, and clean-up cost is with high.

Utility model content

The purpose of this utility model is exactly the problem existing for overcoming above-mentioned background technology, by theory analysis, flow numerical simulation and experimental study, design and a kind ofly block dirty folding shape trashrack for pumping plant, adopt folding shape trashrack to replace the plane trashrack using at present, can reduce the dirty head loss of blocking of trashrack, improve the fluidised form after grid, improve efficiency of pumping station, and it is more easy to make to remove contamination, reduces clean-up cost and use.

The purpose of this utility model is to realize like this, a kind ofly block dirty folding shape trashrack for pumping plant, comprise planar gate body, it is characterized in that, described folding shape trashrack is connected and is combined by upper and lower planar gate body, lower plane grid body vertically or is slightly obliquely installed to Parallel to the flow direction routinely, and upper planar gate body tilts larger to Parallel to the flow direction, and floating thing can be with current along upper planar gate body inclination grid towards upper slippage.

Described upper and lower planar gate body is made up of grizzly bar (1), crossbeam (2), side bar (3) respectively, and grizzly bar is along the incline direction setting of planar gate body.

Described lower plane grid body vertically or is slightly obliquely installed to Parallel to the flow direction, with the angle of horizontal plane be 75 °～90 °.

Described lower plane grid body bottom contacts with flow section bottom, location in the insertion groove of both sides.

Described upper and lower planar gate body is connected to and is articulated and connected, and two planar gate body angles can change.

Described upper and lower planar gate body junction height is lower than the bottom level of floater, to guarantee that floating thing floated lower plane grid body from top, can be under flow action along on planar gate body grid towards on slippage.

The angle of described upper planar gate body and horizontal plane is 15 °～45 °, so that incoming flow floating thing can be under the effect of current along on piece grid towards on slippage, prevent floating thing dive obstruction middle and lower part grid face, reduce the blocked area of floating thing to flow section, thereby reduce to block dirty resistance, be convenient to remove contamination simultaneously.

The utility model is simple and reasonable, manufactures and installs easily, blocks dirty effective.Compared with traditional planar shaped, vertically arranged trashrack, the floating thing (pasture and water) of same volume is little to the degree of depth of its obstruction, blocks sewage potential difference little, blocks dirty resistance little, and after grid, velocity flow profile improves, and main frame operating cost is few; Because dirt accumulates in the water surface, to remove contamination conveniently, the dirt hoisting depth of removing contamination is little, and clean-up cost is few.The utility model can be applicable in pumping plant diversion channel or before water inlet flow channel and intake pool, and expectation pumping station operation expense can be saved more than 6%.Calculate by the similar pumping plant of China pumping plant installation 4,000 ten thousand kW, year operation 1000h, a 0.8 yuan/kWh of electricity price, can save every year 32000000000 yuan, there are great economic results in society.

The utility model is combined by a crossbeam is hinged by upper and lower two grid faces, and grid body is made up of grizzly bar, crossbeam, side bar.Wherein, lower grid face and horizontal plane angle α=75 °～89 °, its height will guarantee the altitude range of incoming flow floating thing in upper piece grid face.Upper piece grid face tilt angle is larger, upper piece grid face and horizontal plane angle β value, with can make dirt in incoming flow can be under current promote along on piece grid towards on slippage be advisable, follow-up pasture and water spread out towards upstream along top grid, β=15 °～45 °, get large value when flow velocity is large, flow velocity hour gets the small value; The length of upper piece grid face wants to deposit the pasture and water dirt of certain volume, guarantee not have before removing contamination unnecessary pasture and water dive stop up under piece grid face.

According to the accumulation shape analysis of blocking dirt before the grid that dirty test obtains, the gathering situation of same volume pasture and water before folding shape trashrack and planar shaped trashrack grid, before folding shape trashrack grid, dirt length is in the horizontal direction greater than planar shaped trashrack, but the grid face plug depth of folding shape trashrack is little.

Compared with single fan planar shaped trashrack, the pasture and water of same volume, the utility model folding shape trashrack has reduced the plug depth of grid faces, blocks dirty head loss and reduces, and after grid, fluidised form is improved, and pumping plant main frame operating cost reduces more than 6%, more easy to remove dirt, clean-up cost reduces.

According to experiment and numerical simulation study, in the time that before grid, pasture and water dirt gathers certain thickness, dirt inside only has little current to pass through, and dirty head loss that what it caused block is stopped up with the fluid-tight entity of same shape before grid the head loss causing and substantially equated, flow field, front and back is close.So, dirt before grid can be regarded as to waterproof entity simplifies blocking dirty model, use ANSYS CFX software, adopt VOF method numerical computations prototype pumping plant to adopt folding shape and planar shaped trashrack to block head loss and trashrack front and back velocity flow profile thereof that dirt causes, and research and analyse.

Trashrack blocks the dirty numerical computation method that flows and comprises following step:

A. when basis is blocked dirty test, roll over form and the front dirt of pumping plant of the front dirt gathering of shape and planar shaped trashrack and assemble the field observation of situation, set up the geometrical model of numerical computations by dirt gathering shape before grid, can obtain different computation models by dirt volume before flow velocity, grid before the depth of water, grid before change grid.

B. the geometrical model of setting up is carried out to non-structured grid division, near local cypher grizzly bar and crossbeam.

C. the governing equation of numerical computations comprises continuity equation, Reynolds average equation, adopts k-ε turbulence model.

$\frac{\∂\mathrm{\ρ}}{\∂t}+\▿\left(\mathrm{\ρu}\right)=0---\left(1\right)$

$\frac{\∂\left(\mathrm{\ρ}{u}_i\right)}{\∂t}+\frac{\∂\left(\mathrm{\ρ}{u}_i{u}_j\right)}{\∂x_j}=\mathrm{\ρ}{f}_i-\frac{\∂p}{\∂x_i}+\frac{\∂{\mathrm{\τ}}_{\mathrm{ij}}}{\∂x_j}---\left(2\right)$

In formula: the density that ρ is fluid; P represents the pressure of fluid micellar; u _i, f _i, x _ibe respectively speed, unit mass power and the coordinate of i direction; τ _ijfor fluid micellar surface viscosity shearing stress τ _ijcomponent.

K equation: $\frac{\∂}{\∂x_j}[\mathrm{\ρ}{v}_{j}k-(\mathrm{\μ}+\frac{{\mathrm{\μ}}_t}{{\mathrm{\σ}}_k})\frac{\∂k}{\∂x_j}=\mathrm{\ρ}(p_k-\mathrm{\ϵ})---\left(3\right)$

ε equation: $\frac{\∂}{\∂x_j}[\mathrm{\ρ}{v}_j\mathrm{\ϵ}-(\mathrm{\μ}+\frac{{\mathrm{\μ}}_t}{{\mathrm{\σ}}_{\mathrm{\ϵ}}})\frac{\∂\mathrm{\ϵ}}{\∂x_j}]=\mathrm{\ρ}\frac{\mathrm{\ϵ}}{k}(C_{\mathrm{\ϵ}1}{p}_k-C_{\mathrm{\ϵ}2}\mathrm{\ϵ})---\left(4\right)$

In formula: μ _tfor whirlpool group coefficient of viscosity,

pk is tubulence energy generating item,

empirical coefficient C _{1 ε}=1.44, C _{2 ε}=1.92, C _μ=0.09, σ _k=1.0, σ _ε=1.3

D. adopt the distribution of liquid volume fraction (VOF) model following trashrack front and back liquid level.VOF model definition liquid volume component function alpha (ratio of liquid volume and this unit volume in unit), in each unit, the volume fraction sum of water and air is 1.If α _wrepresent the volume fraction of water, the volume fraction α of air _acan be expressed as α _a=1-α _win a unit, the volume fraction of water has 3 kinds of situations, i.e. α _w=0,1 or between 0 and 1, respectively be full of gas, be full of water and comprise 3 kinds of situations of aqueous vapor interface corresponding.As long as the volume fraction of water and air in flow field is everywhere all known, the unknown quantity that all other water and airs are total and characterisitic parameter can represent with the weighted average of volume fraction.

E. the finite volume method of the discrete employing staggered-mesh of equation.By variable p, k, ε, α is placed in control volume center, speed control volume and pressure control volume interlaced arrangement, the discrete employing power function of convection current-diffusion term.At aqueous vapor interface, discontinuous due to physical property easily produces numerical value diffusion in calculating, therefore, in the time of discrete volume function alpha governing equation, adopts Upwind Schemes, control time step-length effectively in calculating.

F. given zoning fringe conditions.This zoning adopts pressure inlets, quality outlet, admission section top (water surface), a given atmospheric pressure.Flow and adopt Wall-function in near-wall region, wall adopts without slippage, adiabatic boundary condition.

G. numerical computations V-arrangement and planar shaped trashrack block dirty flowing, and result of calculation is studied, analyzed.

The method of employing numerical computations can calculate comparatively accurately pumping plant and block dirty head loss and Flow Field Distribution thereof.Numerical result shows: when flow velocity before the depth of water, grid before grid certain, before the pasture and water obstruction grid of same volume time, compared with planar shaped trashrack, folding shape trashrack dirt plug depth is little, and grid face area of passage is large, blocks sewage potential difference little, after grid, fluidised form is good, not only reduce pumping plant main frame energy consumption, also made to remove contamination more convenient, reduced clean-up cost and use.

Accompanying drawing explanation

Fig. 1 is the utility model folding shape trashrack structural representation.

Fig. 2 is pasture and water accumulation shape (retain the above sub-fraction of the grid body water surface, remove topmost portion) before the utility model folding shape trashrack grid.

Fig. 3 is traditional front pasture and water accumulation shape of planar shaped trashrack grid.

Fig. 4 is that traditional planar shaped trashrack blocks the dirty computation model that flows.

Fig. 5 is that the utility model folding shape trashrack blocks the dirty computation model that flows.

Fig. 6 is that the utility model folding shape trashrack blocks the dirty computing grid that flows.

Fig. 7 is the utility model folding shape trashrack forward and backward water level while blocking dirt.

Fig. 8 is traditional planar shaped trashrack forward and backward water level while blocking dirt.

Forward and backward velocity flow profile when Fig. 9 the utility model folding shape trashrack blocks dirt.

Figure 10 is traditional planar shaped trashrack forward and backward velocity flow profile while blocking dirt.

In figure: dirt before planar gate body, 5 lower plane grid bodies, 6 grid on grizzly bar 1, crossbeam 2,3 side bars, 4.

The specific embodiment

According to the accumulation shape analysis and the numerical simulation study that block dirt before the grid that dirty test obtains, adopt the method for numerical computations, and result of calculation is studied, analyzed, block a dirty folding shape trashrack for pumping plant, as shown in Figure 1 and Figure 2, in employing, planar gate body 4,5 connections of lower plane grid body combine, lower grid body is vertical or approach at right angle setting and place, upper piece grid body tilts to install to be placed, and floating thing can be by drag force, with current along upper piece grid body inclination grid towards upper slippage.Upper and lower planar gate body is installed and is connected to form by grizzly bar 1, crossbeam 2, side bar 3 respectively, and grizzly bar is vertically placed.

Upper and lower two planar gate bodies are connected to and are articulated and connected.

Lower grid body is vertical or approach at right angle setting and place, and the grid face of lower grid body becomes the angle of 75 °～90 ° with horizontal plane, and lower grid body overhead height be lower than the bottom level of floater so that floating thing can enter piece under the altitude range of piece grid body grid face.

Upper piece grid body tilts to install to be placed, and the grid face of upper piece grid body becomes the angle of 15 °～45 ° with horizontal plane so that incoming flow floating thing can be under the effect of current on edge piece grid towards on slippage, reduce the obstruction of floating thing to grid face.

Adopting CFD(computational fluid dynamics) method calculates and blocks dirty flowing, and 4～11 certain pumping plant select respectively folding shape trashrack and planar shaped trashrack to block dirt by reference to the accompanying drawings, are described further blocking dirty flowing.

It is that before 3.3m, grid, flow velocity is that before 1.0m/s, grid, to assemble the long 3.5m of dirt group (pasture and water), grid face plug depth be the front dirt accumulation shape of grid and numerical computations model when traditional planar shaped trashrack blocks dirt while being 75 ° 1.75m, trashrack inclination angle that Fig. 3, Fig. 4 are respectively before grid the depth of water; Fig. 5 is during with Fig. 4 same depth of water, flow velocity, and the dirt of same volume is gathered in computation model before folding shape trashrack, and now the plug depth of grid face be only 1.25m, and the length that before grid, dirt is rolled into a ball is 4.75m.Assemble before the size, grid of dirt group the depth of water and grid before grid by changing before, flow velocity obtains multiple computation model.

Fig. 6 divides for folding shape trashrack computation model grid, adopts the stronger non-structured grid of compliance to carry out subdivision, near local cypher grizzly bar and crossbeam, and its grid sum 1073782, other computation model Meshing Methods are identical.

Fig. 7 and Fig. 8 are respectively water level before above-mentioned situation folding shape trashrack and planar shaped trashrack, after grid.When planar shaped trashrack grid face plug depth is 1.75m, block the about 0.52m of sewage potential difference; When the dirt of same volume is gathered in before folding shape trashrack grid, grid face plug depth is 1.25m, and the corresponding sewage potential difference of blocking is only 0.22m.Pasture and water can move upward along folding inclination angle, shape trashrack top larger grid face under the effect of current, reduce the plug depth of grid face, thereby while making the pasture and water of same volume stop up above-mentioned two kinds of trashracks, it is much smaller that folding shape trashrack blocks sewage potential difference.If pump station device lift is 5m, adopt folding shape trashrack, pumping plant can be saved main frame operating cost more than 6%, and can save clean-up cost and use.

Fig. 9 and Figure 10 are respectively above-mentioned situation folding shape trashrack and planar shaped trashrack blocks velocity flow profile situation in longitudinal section in dirty computation model.Current are walked around the front obstruction of grid, do not stop up section from grid face and flow through, before grid bottom approach velocity along with area of passage reduce increase gradually, and after grid, bottom velocity is large, top flow velocity reduces and has backflow in a big way, and after planar shaped trashrack grid, fluidised form is more disorderly.

Claims (3)

1. block a dirty folding shape trashrack for pumping plant, comprise planar gate body, it is characterized in that, described folding shape trashrack is connected and is combined by upper and lower planar gate body, and lower grid body is vertical or approach at right angle setting and place; Upper piece grid body is installed and is placed with larger Parallel to the flow direction angle of slope, guarantees that floating thing can be by drag force along grid towards upper slippage; Described upper and lower planar gate body is made up of grizzly bar (1), crossbeam (2), side bar (3) respectively, and grizzly bar is along the incline direction setting of planar gate body; Described upper and lower planar gate body is connected to and is articulated and connected, and upper and lower planar gate body angle can change.

2. according to claim 1ly a kind ofly block dirty folding shape trashrack for pumping plant, it is characterized in that, the angle of described lower plane grid body and horizontal plane is 75 ° ~ 90 °, lower planar gate body overhead height be lower than the bottom level of floater, enters the inclination grid face of a planar gate body so that floater can float lower piece planar gate body top.

3. according to claim 1ly a kind ofly block dirty folding shape trashrack for pumping plant, it is characterized in that, the angle of described upper planar gate body and horizontal plane is 15 ° ~ 45 °, when flow velocity is large, get large value, flow velocity hour gets the small value, so that incoming flow floating thing can be under the effect of current along on piece grid towards on slippage, reduce the obstruction of floating thing to grid face.

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