CN101672024A - Gravity pressure water delivery system with automatic-adjusting weir well - Google Patents

Abstract

The invention relates to a gravity pressure water delivery system with an automatic-adjusting weir well, in particular to a hydraulic adjustment and control system used for water delivery engineering.The system comprises: an adjusting weir well which is arranged between a water inlet and a water outlet and connected through a pipeline. The weir well comprises: a weir well water inlet connected with an upstream pipe at the bottom part of the inlet breast wall of the adjusting weir well, wherein two sides of the inlet breast wall are respectively connected with the side wall of the weir well; the outlet breast wall of the adjusting weir well is connected with the side wall of the weir well and the bottom part of the outlet breast wall is a weir well water outlet connected with a downstreamwater delivery pipe; an overflow weir is arranged at the bottom part of a shaft between the inlet and the outlet breast wall and lies across between two side walls; for longer gravity pressure water delivery engineering, different water delivery flow rates need different water heads; the adjusting weir well can automatically adjust the water heads; when the water delivery flow rate is less than design flow rate, surplus water heads are consumed in sections and the internal water pressure of a pressure pipe culvert is reduced; and at the minimum operating flow rate, the minimum pressure requirement indispensible to the pipe culvert is kept. The water delivery system not only has simple hydraulic control, but also ensures the safe and reliable water delivery of the engineering.

Description

A kind of gravity that has automatic regulating weir well has the pressure water-carriage system

Technical field

The present invention relates to a kind of gravity that has automatic regulating weir well has the pressure water-carriage system, is a kind of water conservancy project system, is a kind of waterpower regulator control system that is used for water delivery engineering.

Background technology

Water-carriage mode comprises the water delivery of no ballast power, the water delivery of ballast power is arranged, pressurization water delivery, gravity and pressurization combination water delivery etc., in the ordinary course of things, when enough utilized water delivery topographical elevation difference, should preferentially select to have ballast power water-carriage mode.But it is the utilized head that the water delivery of ballast power is arranged that water delivery plays terminal hydraulic height difference.After definite water delivery design discharge, but utilize utilized head as far as possible, reduce the water-supply-pipe caliber as much as possible, realize few as much as possible investment, produce greatest benefit.Certainly, the water-supply-pipe flow velocity is big more, and the water hammer that may cause during operation boosts high more.For preventing that pipeline from destructive water hammer accident taking place, general requirements water-supply-pipe flow velocity is not more than 3m/s.Therefore, but the gravity aqueduct economic pipe size is exactly to determine that by making full use of existing utilized head transfer designs flow promptly the water delivery caliber is to make full use of under the existing head condition, is determined by maximum stream flow, that is to say not have dump energy when under the design discharge operating mode, moving.Because in the water delivery process, the water delivery flow changes, generally adopt at present control valve (device that can energy dissipating can control stream again) is set in pipe end or centre.Like this, following situation will occur: when being lower than the design discharge operation, head loss reduces, and produces dump energy, and water-supply-pipe downstream line pressure increases more.Correspondingly bring following problem: pipeline pressure increases, and the one, increase construction investment, the 2nd, be unfavorable for safe water delivery; Require the strictness of control valve scheduling control program, otherwise produce bigger surge pressure, jeopardize engineering safety; To the sensitiveness height of foreign material such as ice, foreign matter, potential risk is big, operational management complexity, overhead cost height; Ancillary facility and annexes such as major diameter butterfly valve, superpressure relief valve, reduced pipe, branched pipe, bend pipe need be set, and power load rank height need be provided with the high electromechanical equipment of security reliability, and the engineering complicated layout is invested higher; Particularly the critical component of control valve need rely on abroad, and maintenance in the future, maintenance and renewal are controlled by the people, and is very unfavorable to engineering operation and management.

Summary of the invention

For solving prior art problems, the present invention proposes a kind of gravity that has automatic regulating weir well the pressure water-carriage system is arranged, described method is used a kind of facility of regulating weir well, the present invention compares with control valve, has following outstanding advantage: at different flow, automatically regulate head, operation control is simple and convenient; Just in time opposite during with the employing control valve, pipeline pressure is maximum during design discharge, greatly reduces pipeline pressure, both reduces investment outlay, and helps safe water delivery again; Know-why is simple, and hydraulic performance is good, and fluidised form is steady; The waterpower regulating effect is good, and the engineering safety reliability is secure; Required electromechanics, plant equipment seldom, engineering management is easy; Engineering design is simple, easy construction, and the engineering maintenance workload is little, and maintenance cost is low.

The object of the present invention is achieved like this: a kind of gravity that has automatic regulating weir well has the pressure water-carriage system, described system comprises: the upstream water delivery water inlet and the downstream water delivery delivery port that is arranged on water side that are arranged on water supply side, it is characterized in that, be connected at least one regulating weir well by pipeline between described water delivery water inlet and the water delivery delivery port, described regulating weir well comprises: the weir well water inlet bottom the import breastwork of regulating weir well that is connected with upstream line, described import breastwork both sides connect weir well side wall respectively, what be connected with described weir well side wall is the outlet breastwork of regulating weir well, and the bottom of described outlet breastwork is the weir well delivery port that is connected with the downstream aqueduct; It is the vertical shaft of the regulating weir well of rectangle that import breastwork, outlet breastwork, two side weir Jing Qiang form the cross section, the well head on described vertical shaft top opens wide or covers the overburden that air can flow, overflow weir is arranged at the silo bottom between import breastwork and the outlet breastwork, and cross-arm is between both walls.

The beneficial effect that the present invention produces is: (1) has the pressure water delivery engineering for long gravity, the required head difference of different water delivery flows, water-carriage system with regulating weir well can be regulated head automatically, during less than design discharge, segmentation consumes head more than needed, and reducing has pressure pipe to contain internal water pressure, when minimum operation flow, can keep the necessary minimum pressure requirement of pipe culvert again, waterpower control was both simple, can guarantee the reliable water delivery of engineering safety again;

(2) change layout regulating weir well according to terrain, can reduce the pipe culvert buried depth, reduce to press in the pipe culvert, reduce construction investment;

(3) many regulating weir wells are set, help the control of waterpower inertia, be convenient to operational management;

When (4) water-carriage system was cut off the water, water body still remained in the pipe culvert, made pipe culvert maintain pressure condition, avoided long distance to have and pressed water-carriage system to start preceding low discharge, long-time water-filling situation once more, had improved the water delivery timeliness greatly;

(5) in the long distance water transfer project, be provided with arm or bleeder midway, or terminal directly and Other Engineering when joining, the regulating weir well has the effect of pressurize;

(6) the regulating weir well has the effect of maintenance lock, can be that engineering is overhauled completely, segmentation maintenance, the maintenance of wrong hole facilitate condition;

(7) have the water-carriage system stem of regulating weir well, middle location chance burst accident (as the pipeline damage accident), the regulating weir well has obstruct, restraining effect, avoids the water yield to lose in a large number, can save water resource;

(8) the water-carriage system end with regulating weir well is met burst accident (as the pumping plant accident), and the regulating weir well has segmentation and weakens the water attack energy, and segmentation cuts off or reduces surge wave, and each weir well plays the surge shaft effect;

(9) during changes in flow rate, the regulating weir well has the effect that weakens hydraulic oscillation and prevent column separation;

(10) the regulating weir well has the effect that suppresses water level fluctuation, guarantees water-carriage system pressure, stability of flow, and helps flow measurement;

(11) the regulating weir well has and prevents that bubble from entering the effect in pressure flow road, downstream, guarantees conveyance power of water and engineering safety.

Description of drawings

The invention will be further described below in conjunction with drawings and Examples.

Fig. 1 is that the embodiment of the invention one described a kind of gravity that has automatic regulating weir well has the water-carriage system of pressure vertical section schematic diagram;

Fig. 2 is that the embodiment of the invention two described a kind of gravity that have automatic regulating weir well have the regulating weir well vertical section schematic diagram of pressing water-carriage system;

Fluidised form schematic diagram when Fig. 3 is the big flow of the embodiment of the invention two described regulating weir wells, high water level;

Fluidised form schematic diagram when Fig. 4 is the embodiment of the invention two described regulating weir well low discharges, low water stage;

Fig. 5 is the vertical section schematic diagram of the embodiment of the invention three described regulating weir wells;

Fig. 6 is the vertical section schematic diagram of the embodiment of the invention four described regulating weir wells;

Fig. 7 is the vertical section schematic diagram of the embodiment of the invention five described regulating weir wells;

Fig. 8 is the vertical section schematic diagram of the embodiment of the invention six described regulating weir wells;

Fig. 9 be the embodiment of the invention six described regulating weir wells do not establish wave absorption plate low discharge the time bubble overflow and water level fluctuation situation schematic diagram;

Figure 10 is that the embodiment of the invention six described regulating weir wells bubble when establishing wave absorption plate low discharge is overflowed and water level fluctuation situation schematic diagram.

The specific embodiment

Embodiment one:

Present embodiment is that a kind of gravity that has automatic regulating weir well has the pressure water-carriage system, as shown in Figure 1.The described system of present embodiment comprises: be arranged on the upstream water delivery water inlet 3 of water supply side and be arranged on the downstream water delivery delivery port 6 of water side, be connected at least one regulating weir well 4,401 by pipeline 5 between water delivery water inlet and the water delivery delivery port.The regulating weir well comprises: the weir well water inlet 8,801 in import breastwork 7,701 bottoms of regulating weir well that is connected with upstream line, import breastwork both sides connect weir well side wall respectively, what be connected with weir well side wall is the outlet breastwork 10,1001 of regulating weir well, and the bottom of outlet breastwork is the weir well delivery port 11,1101 that is connected with the downstream aqueduct.It is the vertical shaft of the regulating weir well of rectangle that import breastwork, outlet breastwork, two weir well side walls form the cross section, the well head on vertical shaft top opens wide or covers the overburden that air can flow, overflow weir 9,901 is arranged at the silo bottom between import breastwork and the outlet breastwork, and cross-arm is between both walls.

The water-filled process of whole water-carriage system: the upstream line that current enter the first regulating weir well by the water delivery water inlet, the upstream line by the first regulating weir well enters the first regulating weir well; Current begin to assemble at the upstream face of first overflow weir under the stopping of first overflow weir of the first regulating weir well, and the upstream line of the whole first regulating weir well is full of water when water level is increased to the height of water delivery water inlet; Water level continues to rise to the first overflow weir top, and is overflowed by the first overflow weir top, and current enter the first overflow weir back side, one side; Current enter the first overflow weir back side, one effluent and cross the wave absorption plate bottom of the first regulating weir well and enter the open channel section of the first regulating weir well, and continue to flow into the downstream line of the first regulating weir well; The downstream line of the first regulating weir well also is the upstream line of the second regulating weir well, and current enter the second regulating weir well by the upstream line of the second regulating weir well; Current begin to assemble at the upstream face of second overflow weir under the stopping of second overflow weir of the second regulating weir well, and the upstream line of the whole second regulating weir well is full of water when water level is increased to the weir well delivery port height of the first regulating weir well; Water level continues to rise to the second overflow weir top, and is overflowed by the second overflow weir top, and current enter the second overflow weir back side, one side; Current enter the second overflow weir back side, one effluent and cross the wave absorption plate bottom of the second regulating weir well and enter the open channel section of the second regulating weir well, and continue to flow into the downstream line of the second regulating weir well; The downstream line of the second regulating weir well also is the upstream line of the 3rd regulating weir well, and current enter the 3rd regulating weir well by the upstream line of the 3rd regulating weir well; Current begin to assemble at the upstream face of the 3rd overflow weir under the stopping of the 3rd overflow weir of the 3rd regulating weir well, and the upstream line of whole the 3rd regulating weir well is full of water when water level is increased to the weir well delivery port height of the second regulating weir well; Continue circulation and be full of water until upstream line with all regulating weir wells; After last regulating weir well was full of water, current overflowed the back and flow out the water delivery delivery port from the top of last overflow weir, finish water filling process.

Little operation flow water delivery process: according to operation flow size, open inlet gate by certain open degree, current are entered the upstream line of the first regulating weir well by the water delivery water inlet, owing to be full of water in the pipeline, the flow of water delivery water inlet is with the form transmission of compression wave, pressure-wave propagation speed is very fast, and the changes in flow rate of water delivery water inlet is passed to the first regulating weir well very soon.During the low discharge water delivery, required head is little, and the overflow weir level of tail water is lower, and therefore, current overflow on the first overflow weir top of the first regulating weir well, and freely falls in the water body in downstream, weir with bigger drop and (to be also referred to as free weir flow).Because of there is certain water cushion in the downstream, weir, so produce hydraulic jump, the current bump is arranged the whirlpool beam that disappears down simultaneously, and energy is further eliminated, and can eliminate most of energy like this, and under the homogenizing current and the whirlpool effect that disappears of the whirlpool beam that disappears, current are comparatively steady.Current continue to flow through the open channel section that the wave absorption plate bottom of the first regulating weir well enters the first regulating weir well, and when flowing through the wave absorption plate, underwater bubble is overflowed before the wave absorption plate, and water level fluctuation reduces, and current are more steady.In the open channel section, because the homogenizing current of the whirlpool beam that disappears and the whirlpool effect that disappears, current enter the downstream line of the first regulating weir well very reposefully.The downstream line of the first regulating weir well also is the upstream line of the second regulating weir well, current enter the second regulating weir well by the aboveground play pipe of second regulating weir road, current overflow on the second overflow weir top of the second regulating weir well, and freely fall in the water body in downstream, weir with bigger drop, produce hydraulic jump, the current bump is arranged the whirlpool beam that disappears down simultaneously, and under the further energy dissipating of whirlpool beam that disappears, homogenizing current and the whirlpool effect that disappears, current are comparatively steady.Current continue to flow through the open channel section that the wave absorption plate bottom of the second regulating weir well enters the second regulating weir well, suppress water level fluctuation and make under the effect that bubble overflows in advance at the wave absorption plate, and current are more steady.The homogenizing current of whirlpool beam and the whirlpool effect that disappears because the open channel section disappears, current enter the downstream line of the second regulating weir well very reposefully.The downstream line of the second regulating weir well also is the upstream line of the 3rd regulating weir well, continues circulation and overflows back outflow water delivery delivery port from the top of last overflow weir until current, realizes little operation flow water delivery process.

When flow increases, further open inlet gate by certain open degree, the upstream line that current enter the first regulating weir well by the water delivery water inlet, the changes in flow rate of water delivery water inlet is passed to the first regulating weir well with the form of compression wave.Because flow increases, required head increases, and overflow weir upstream and downstream water level increases, and level of tail water value added is big, and drop diminishes.When the weir level of tail water exceeds weir crest to certain limit, cross the jacking that sluice stream is subjected to the level of tail water, be the so-called weir flow that floods.Current overflow on the first overflow weir top of the first regulating weir well, fall in the water body in downstream, weir with less drop.Because of the weir downstream water depth is bigger, produce submerged hydraulic jump, the while current clash into upper and lower two arranges the whirlpool beam that disappears, and energy is further eliminated, and like this, energy dissipation rate further improves, and water level fluctuation is little, and bubbles volume is few.Under two rows disappeared the homogenizing current and the whirlpool effect of disappearing of whirlpool beam, current were more steady.Current continue to flow through the open channel section that the wave absorption plate bottom of the first regulating weir well enters the first regulating weir well, when flowing through wave absorption plate bottom, because of the weir downstream water depth bigger, the wave absorption plate is less to the ratio of the aperture height of regulating weir shaft bottom plate and the depth of water, being equivalent to aperture height diminishes, the inhibition of wave absorption plate is fluctuateed and is stopped that the effect of bubble strengthens, and effect is more obvious, makes that the current of open channel section are more steady.In the open channel section, the homogenizing current of whirlpool beam and the whirlpool effect that disappears because two rows disappear, current enter the downstream line of the first regulating weir well very reposefully.The downstream line of the first regulating weir well also is the upstream line of the second regulating weir well, current enter the second regulating weir well by the aboveground play pipe of second regulating weir road, current overflow on the second overflow weir top of the second regulating weir well, and fall in the water body in downstream, weir with less drop, produce submerged hydraulic jump, under further energy dissipating, the homogenizing current of whirlpool beam and the whirlpool effect that disappears, current are more steady because two rows disappear.Current continue to flow through the open channel section that the wave absorption plate bottom of the second regulating weir well enters the second regulating weir well, suppress water level fluctuation and make under the effect that bubble overflows in advance at the wave absorption plate, current are more steady, under open channel section two rows disappeared the homogenizing current and the whirlpool effect of disappearing of whirlpool beam, current entered the downstream line of the second regulating weir well very reposefully.The downstream line of the second regulating weir well also is the upstream line of the 3rd regulating weir well, continues circulation and overflows back outflow water delivery delivery port from the top of last overflow weir until current, realizes increasing the process of flow.

When the water delivery flow reaches design scale, the overflow weir water levels of upstream and downstream further increases, water levels of upstream and downstream is very approaching, do not have tangible drop phenomenon, flow-shape still belonged to and flooded weir flow this moment, and only degree of flooding is big, this moment, the weir crest depth of water was also bigger, there is not air bubble problem in current in overflow weir crest horizontal flow mistake, and flow-shape is the most steady.Each regulating weir well of line of project all reaches this state, that is to say, the regulating weir well plays the not-go-end head with water delivery engineering and all uses water delivery.

Embodiment two:

Present embodiment is the improvement of embodiment one, is the refinement of embodiment one about overflow weir, as shown in Figure 2.The overflow weir of the described regulating weir well of present embodiment is the broken line practical weir type of cavetto, described import breastwork is to distance (or the title " overflow weir upstream distance " at overflow weir center, or more be called for short " upstream, weir ") be not less than weir well water inlet height, the height of described overflow weir is: during minimum operation flow, weir well water inlet depth of immersion is not less than 1.0 meters, weir well outlet depth of immersion is not less than 1.5 meters, the overflow weir crest to the height of the well head of regulating weir well more than or equal to weir well water inlet height, described overflow weir center is to distance (or the title " overflow weir downstream distance " that exports between the breastwork, or more be called for short " downstream, weir ") when being not less than minimum operation flow, overflow weir top overflow falls distance and adds hydraulic jump length, adds 2.5 times hydraulic jump length again.

The weir type of overflow weir: in engineering is used, can different types be made on the weir according to different construction conditionses and instructions for use.According to weir profile and thickness and water stream characteristics, the weir is divided into types such as sharp-crested weir, practical weir and broad crested weir, practical weir can be divided into broken line shape practical weir and shaped form practical weir, and the shaped form practical weir comprises types such as WES type, wet strange type, Ke-Ao type and hump type.According to weir body activity, also the weir can be divided into fixedly and movable, gate, water-filling or air filling type rubber dam bag promptly belong to movable.What present embodiment used is the broken line practical weir type of cavetto, and this is a kind of improvement of broken line practical weir, and the weir crest of broken line practical weir is adjusted into the circular arc of three sections different radiis, like this, has both improved conveyance capacity, is convenient to construction control again, guarantees workmanship.

Definite principle of weir crest elevation is: the one, and the assurance pipe culvert is imported and exported the requirement of satisfying certain depth of immersion respectively; The 2nd, during the design discharge service condition, the head loss of regulating weir well is as far as possible little.

Theoretically, the weir crest elevation should satisfy following condition simultaneously: when minimum operation flow, the conduit entrance depth of immersion should be not less than 1.5m, and the pipe outlet depth of immersion is not less than 1.0m; When design discharge, the weir crest depth of water should not be less than duct height.See Fig. 1.Like this, just can determine the weir crest elevation.If can not satisfy above-mentioned two conditions simultaneously, can take to reduce the measure of pipeline.Among Fig. 1 1. line be design discharge pressure slope line; Pressure slope line when 2. line is minimum operation flow; D is the aqueduct height; h ₁Pipeline is imported and exported water-head, the i.e. required head of water delivery during for minimum operation flow; h ₂Weir, the downstream weir crest depth of water during for minimum operation flow; h ₃Be the depth displacement of weir crest and upstream line import, h ₃〉=1.5-h ₁-h ₂, p ₁+ h ₂-D 〉=1.0.

For long distance water transfer project, local losses and kinetic head proportion in total losses is very little, be generally less than 5%, can ignore during calculating, moreover, a regulating weir well is equivalent to pressure conduit and turns 4 right angles, under the design discharge, only lose 4 flow velocity heads, therefore, the length of regulating weir well also be can't help the decision of this principle of minimum head loss, and the engineering significance and the necessity of pursuit minimum head loss painstakingly are little.

Overflow weir center to center distance import breastwork distance L ₁, should be principle to be not less than duct height, see Fig. 2.

The overflow weir center is to the distance L that exports breastwork ₂Determine, should with guarantee fluidised form steadily, water level and stability of flow, prevent that bubble from entering the downstream pressure conduit is principle.Because the regulating weir well is different from general hydraulic structure, and darker water cushion is arranged behind its weir, still there is not definite hydraulic jump length computation formula at present.According to the waterpower characteristics of regulating weir well, determine behind the weir length by overflow fall distance, hydraulic jump length, the back segment length that jumps determines.For safety, press 30m ³/ s～60m ³The overcurrent achievement of/s (free weir flow fluidised form) is calculated, and its design formulas is as follows:

1. section depth of water h before jumping ₄

In the formula: ${\mathrm{<figure-callout\; id="4"\; label="h"\; filenames="A2009100939690027H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_4=\frac{q}{\mathrm{\&phi;}\sqrt{2g(E_0-h_4)}}$

Q---discharge per unit width, q=Q/b, Q represents flow, and b represents the width of the cross-section of river;

φ---efflux coefficient is got φ=1.0;

E ₀---total head;

h ₄---the section depth of water before jumping, the cross-section of river of hydraulic jump surface roller starting point is called the preceding section that jumps, and the depth of water of this section part is called the preceding section depth of water that jumps.

2. not you count Fr at moral ₁

${\mathrm{Fr}}_1=\frac{\mathrm{<figure-callout\; id="4"\; label="q\; g\; h"\; filenames="A2009100939690027H1.png"\; state="\{\{state\}\}">q</figure-callout>}}{\sqrt{g}{h_{}}^{}}$

In the formula:

Fr ₁---for not your moral number of section current before jumping, represent the inertia force of current and the relativity of two kinds of effects of gravity; Other is the same.

3. back section depth of water h jumps ₅

${\mathrm{<figure-callout\; id="5"\; label="h"\; filenames="A2009100939690027H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_5=\frac{1}{2}{h}_4(\sqrt{1+8F{r_1}^2}-1)$

In the formula:

h ₅---the back section depth of water that jumps, the cross-section of river of hydraulic jump surface roller end is called the back section that jumps, and the depth of water of this section part is called the back section depth of water that jumps.Other is the same.

4. overflow falls apart from l ₁

$l_1=1.64\sqrt{H_0(p+0.24H_0)}$

In the formula:

l ₁---the horizontal range of water body impelling;

H ₀---weir crest total head, H ₀=h _On+ υ ²/ 2g;

P---it is poor to fall.

5. hydraulic jump length l ₂

l ₂＝4.3h ₅

In the formula:

l ₂-one hydraulic jump length, section is to the horizontal range of the back section that jumps before promptly jumping.

6. the back segment length l jumps ₃

l ₃＝2.5l ₅

7. the weir tract is the overflow weir center to the total length l that exports breastwork:

l＝l ₁+l ₂+l ₃

So the overflow weir center is when exporting distance between the breastwork and be not less than minimum operation flow, overflow weir top overflow falls distance and adds hydraulic jump length, adds 2.5 times hydraulic jump length again.

Because the hydraulic characteristic(s) of the described regulating weir well of present embodiment has certain particularity, the data that can use for reference seldom for this reason, has been carried out special hydraulic model test.

Through to the analysis of weir type with than choosing, adopt the broken line type practical weir type of cavetto.According to each weir height of weir, model testing is got two kinds of overflow weirs and is tested as typical weir, a kind of higher weir and a kind of lower weir.Now relevant test result is summarized as follows:

(1) regulating weir well water head regulating power

Regulating weir well water head regulating power be one about relative water depth h/P behind the weir ₂(depth of water h and downstream height of weir P behind the weir ₂Ratio) function, at the build one on weir regularly, the regulating weir well water head amplitude of accommodation reduces with the rising of relative water depth, is tending towards constant at last, and is subjected to the influence of flow and not obvious.

Draw by hydraulic test: no matter high weir or low weir, during big flow, weir level of tail water height, regulating power all are positioned at mild section of curve bottom, and the weir water levels of upstream and downstream differs less, when that is to say excessive flow head loss less, see Fig. 3; During low discharge, the weir level of tail water is low, and regulating power all is positioned at the steep section on curve top, and the weir water levels of upstream and downstream differs bigger, has significantly drop phenomenon, and the drop amplitude is bigger, when that is to say low discharge head loss bigger, see Fig. 4.

Owing to have the existence of the overflow weir of certain altitude, the flow direction in the upstream line is adjusted into upwards by horizontal direction, flow to the downstream through the overflow weir crest.During low discharge, current are freely fallen in the water body before the downstream line import (being also referred to as free weir flow) by weir crest, overflow weir water levels of upstream and downstream difference is called drop, flow is more little, drop is big more, utilizes this drop just, and the unnecessary head during with low discharge looses in each regulating weir well punishment and consumes, make pipeline pressure line along the line be the segmentation arrangement form, avoided forming a higher continuous pressure line.When flow increases, overflow weir upstream and downstream water level increases, level of tail water value added is big, drop diminishes, and during design discharge, drop is very little, its value only is equivalent to the head loss that pipeline turns 4 right angles, be intrinsic, the minimum head loss of regulating weir well itself, that is to say that the regulating weir well plays the not-go-end head with water delivery engineering and all uses water delivery.Cross sluice stream fluidised form when the regulating weir well utilizes changes in flow rate just and change the automatic adjusting that realizes head automatically.Big this specific (special) requirements of head loss during little, the low discharge of head loss when the regulating weir well satisfies the big flow of water delivery engineering fully.This is the technological core and the marrow of regulating weir well.

In engineering, when the water delivery flow increases, the head increase in demand, each regulating weir level of tail water that ladder is provided with increases, each weir flow attitude is flow through to drowned weir by free weir flow crosses, and drop amplitude (drop) reduces gradually, and the head loss reduces automatically, up to the maximum-norm flow, this moment, every regulating weir all reached the loss minimum state.

When the water delivery flow reduced, head occurred more than needed, and the more former water level of each regulating weir water level reduces, and each regulating weir degree of flooding reduces, and fluidised form flows to free weir flow transition by drowned weir, and drop amplitude (drop) increases, and the head loss increases automatically, eliminated head more than needed.The common coordinative role on many weirs that are provided with by ladder has been eliminated head more than needed automatically when the low discharge water delivery like this, has reduced the internal water pressure that has pressure pipe to contain, and reaches the purpose of safe and reliable conveying different flow.

When flow is decreased to 0m ³/ s when promptly engineering stops water delivery, because the downstream weir crest of pipe culvert section has made the pressure pipe culvert still keep full water state all above crest level this section pipe culvert top between each weir, thereby has pressure pipe to contain the problem of water-filling when having avoided the recovery water delivery again.

In engineering design, the regulating weir well location is put and the seat number should comprehensively be determined than choosing according to technical-economic indexes such as landform, geology, engineering quantity, investment and management operatings.When landform is steep, when drop is big, can arrange many, energy dissipating step by step, so comparatively economy.

(2) regulating weir well conveyance capacity

1. conveyance capacity design formulas:

$Q={\mathrm{\&epsiv;}}_1{\mathrm{\&sigma;}}_s\mathrm{mb}\sqrt{2g}{h}_0^{3/2}$

In the formula:

Q---water delivery flow, m ³/ s;

ε ₁---the side shrinkage factor;

σ _s---flood coefficient;

M---discharge coefficient;

B---the weir is wide, m;

h ₀---weir head, m.

2. discharge coefficient

Discharge coefficient is a comprehensive parameters of reflection water conservancy project overcurrent building conveyance capacity.Different weirs type, the weir of differing heights, its discharge coefficient has nothing in common with each other.

From the hydraulic test data as can be known, weir discharge coefficient has faint increase tendency with the increase of flow; The discharge coefficient of low weir is more slightly larger than the high weir, and the high weir discharge coefficient is 0.433, and the discharge coefficient of low weir is 0.443, and both differences are very little, only differs 2.3%.More than show, use,, be subjected to the effect of altitude on weir also not obvious, fully engineering demands as long as the weir build determines that its discharge coefficient can be thought a definite value from engineering.

3. flood coefficient

The hydraulic boundary conditions of overflow weir obviously is different from the wasteway (weir lock) in channel, the reservoir dam in the regulating weir well, therefore, and to reflecting of flood the experimental study that coefficient carried out system of overflow weir water levels of upstream and downstream to the conveyance capacity influence degree.Studies show that: when the overflow weir level of tail water during a little less than the weir crest elevation, high overflow weir and low overflow weir flood coefficient＜1, this moment, the conveyance capacity of overflow weir was subjected to the influence of the level of tail water, belonged to the critical fluidised form between submerge discharging flow and the free discharge.When overflow weir is submerge discharging flow, floods coefficient and calculate by the pairing fitting formula of high low weir test result, its Changing Pattern is as follows: flood coefficient and reduce with degree of flooding increase; When degree of flooding greater than 0.6 the time, flood coefficient and increase with degree of flooding and sharply reduce.

Embodiment three:

Present embodiment is the improvement of embodiment two, is the refinement of embodiment two, as shown in Figure 5.Between the overflow weir of the described regulating weir well of present embodiment and the outlet breastwork absorption basin 13 is set, at described absorption basin upper horizontal arc horizontally-arranged 3 to 4 whirlpool beams 12 that disappear are set, the described whirlpool beam that disappears is bar-shaped cylinder, and cross-arm highly is higher than the overflow weir crest between both walls.

In order to increase the water cushion degree of depth in overflow weir downstream, improve energy dissipation rate, Yan Jing downstream floor elevation is lower than downstream box culvert inlet floor elevation 1.5m, forms absorption basin, and this pond is connected with downstream box culvert base plate with 1: 1 slope.In order to prevent to produce through funnel whirlpool, the whirlpool beam that disappears is set before the pressure conduit import.

Present embodiment has also carried out hydraulic model test, and model testing is by the relevant portion execution of Ministry of Water Resources's ministry standard " water conservancy project (routine) model testing rules (SL155-95) " and " water conservancy project (special topic) model testing rules (SL156～165-95) ".Model designs by the gravity similarity criterion, and adopting the length guide is λ _L=20 normal model, similar to prototype in order to guarantee the fluidised form in the regulating weir well with water surface linking situation, the simulation context of regulating weir well water worker model except upstream transition section (the upstream aqueduct is gradual change so deserve to be called the trip transition section) to the main part between the downstream transition section (the downstream aqueduct is gradual change so claim the downstream transition section), the runner that also comprises the aboveground trip transition section of regulating weir import upstream side, and there is the water delivery of pressure box culvert in downstream transition section outlet three holes, downstream, and are specific as follows:

High overflow weir regulating weir well has been simulated the runner in the 214m length range, and it is 15 times of box culvert height that there is the simulation length of pressure box culvert in its middle and upper reaches three holes, and it is 20 times of box culvert height that there is the simulation length of pressure box culvert in three holes, downstream.

Low overflow weir regulating weir well has been simulated the runner in the 232m length range, and it is 15 times of box culvert height that there is the simulation length of pressure box culvert in three holes, upstream, and it is 20 times of box culvert height that there is the simulation length of pressure box culvert in three holes, downstream.

The relation of the layout of to the effect that studying the weir of regulating weir well water worker model testing and local losses, weir flow discharge coefficient, groundwork is the observation to experimental phenomena in the test, comprise head loss, discharge coefficient and the measurement of flooding coefficient, and situations such as fluidised form, vortex, bubble effusion, water-level fluctuation are observed.

Arranged 5 pressure measurement sections altogether in all fronts of regulating weir well test model, it is grading ring that the pressure tap on each pressure measurement section all adopts plastic flexible pipe to be communicated with, and is connected with corresponding survey tube then.The piezometric head of each section is communicated with the survey tube by lucite pipe, measures with chaining pin, and the reading of chaining pin is accurate to 0.1mm.It is fixing on the wall to survey tube, to reduce water-level fluctuation, guarantees certainty of measurement.High overflow weir and low overflow weir regulating weir well model respectively are provided with one group and survey tube.Survey tube with high overflow weir regulating weir well before the test is communicated with water filling with lucite pipe respectively, after guaranteeing communicating pipe not have bubble, leaves standstill 24 hours, checks this and organizes each chaining pin benchmark; The chaining pin benchmark of low overflow weir regulating weir well is also used with quadrat method and is checked.

The regulating weir well is provided with 3 flowing pressure survey marks, the pressure fluctuation meter during with record free discharge and submerge discharging flow.

Respectively arrange 3 flow-speed measurement sections on the downstream box culvert of high and low overflow weir regulating weir well model, Parallel to the flow direction is designated as S1, S2, S3 respectively, and they are respectively 7.6m, 26m and 56m to the distance of regulating weir down-hole trip box culvert import.Each section is arranged 3 surveys line, they lay respectively at three holes the middle part of pressing box culvert, and every survey line is arranged 5 measuring points, and measuring point 1 arrives the box culvert base plate apart from 0.20m (former offset, down together), measuring point 2,3,4,5 is respectively 1.2m, 2.2m, 3.2m and measuring point 4.1m apart from box culvert base plate distance.Flow velocity is measured with CSY type photoelectricity current meter, and it starts flow velocity is 2.0cm/s, and the flow velocity signal of each measuring point is by an other cover computer data acquisition system synchronous recording, and the flow velocity that its average is made this measuring point is got in the flow velocity sampling of each measuring point 10 times.

Regulating weir is aboveground, the SEA LEVEL VARIATION in weir, downstream well and the downstream box culvert air vent, adopts the multi-functional wave height recorder of DJ800 type to carry out surveying record.This instrument is multichannel, multifunctional examining examining system, can gather, write down nearly water level, the pressure signal of 64 passages simultaneously, and all measurement signals are all by computer acquisition, record and analysis.In this test, use 3 wave height recorders to measure water-level fluctuation simultaneously, sample frequency is 128 times/second.

Through the test post analysis, the test result of two regulating weir wells is basic identical.

In three flow-speed measurement sections, apart from the downstream the most close regulating weir well of S1 section of pressing box culvert inlet 7.6m is arranged, it is subjected to having the greatest impact of regulating weir down-hole trip effluent attitude, and the velocity flow profile difference under the velocity flow profile of this section and the equal uniform flow situation is bigger; And the S2 section from the regulating weir well spacing from being 26m, big than the S1 section, it is obviously reduced by influence of regulating weir down-hole trip effluent attitude, velocity flow profile is obviously improved, substantially near the velocity flow profile under the equal uniform flow situation; For distance adjustment weir well flow-speed measurement section S3 farthest, velocity flow profile is not subjected to the influence of regulating weir down-hole trip effluent attitude substantially, near the velocity flow profile under the equal uniform flow situation.Hence one can see that, and the downstream beyond the trip of down-hole, distance adjustment weir has the flow-speed measurement section S3 that presses box culvert inlet 56m has in the box culvert of pressure, and current revert to equal uniform flow fluidised form substantially.

Because of the regulating weir well is free weir flow, downstream, weir water level is relatively low, is subjected to the influence of regulating weir well downstream absorption basin simultaneously, and there is the main flow deflection box culvert center line top of pressing box culvert admission section current in the downstream, weir.Influenced by it, in the velocity profile of the flow-speed measurement section S1 of the most close regulating weir well, the flow velocity of top measuring point is obviously bigger, and along with the reduction of point position elevation, flow velocity is the trend that reduces gradually.The velocity flow profile nonuniformity coefficient maximum value of section S1 is 2.37, and the nonuniformity coefficient maximum value of S2 and S3 flow-speed measurement section is no more than 1.40, is significantly less than the S1 section.

At former design attitude and operation flow hour, disappear the whirlpool beam all more than water level, do not have any effect, and the test of front measures and shows that this moment, there was bigger water-level fluctuation in weir, downstream well suppressing water-level fluctuation.

Calculate by total flow mean allocation in box culvert three holes, the distribution ratio that each orifice flow amount accounts for total flow should be 33.3%.Different in flow rate is measured on the section, and the maximum deviation of the ratio 33.3% when the assignment of traffic ratio in each orifice flow road of actual measurement and flow uniform distribution all in 2%, can think that the assignment of traffic of each runner is more even.

Embodiment four:

Present embodiment is the improvement of embodiment two, is the refinement of embodiment two, as shown in Figure 6.Two rows respectively are provided with 4 to 5 bar-shaped column types whirlpool beam that disappears between the overflow weir of the described regulating weir well of present embodiment and the outlet breastwork, the described whirlpool beam cross-arm that disappears is between both walls, disappear whirlpool beam 1201 of next row is horizontal arc horizontally-arranged, be provided with and highly be lower than the overflow weir crest, last one arranges the whirlpool beam 1202 that disappears is the horizontal linear horizontally-arranged, is provided with highly to be higher than the overflow weir crest.

Present embodiment is cancelled the embodiment three dark absorption basin of 1.5m that (being the overflow weir back side) is provided with in the overflow weir downstream for improving fluidised form, improve energy dissipation rate, reducing water level fluctuation, and it is flat making the overflow weir downstream, increases the whirlpool beam that disappears together simultaneously.

Present embodiment carries out hydraulic test, and test method, instrument setting and terms and conditions thereof are identical with embodiment two described tests, have only revised test model, have promptly cancelled the absorption basin in overflow weir downstream, have increased the above-mentioned whirlpool beam that disappears, and test result is as follows:

The whirlpool beam that disappears adopts two-layer beam to arrange that the water-level fluctuation amplitude is the trend of reduction generally, even under minimum operation flow, lower floor disappears the whirlpool beam also substantially below the water surface, and water-level fluctuation is had certain inhibitory action.The water-level fluctuation of regulating weir down-hole trip weir well and the water-level fluctuation in downstream ventilation hole all have reducing in various degree, and it is favourable adopting two-layer beam to arrange water-level fluctuation.

After the two-layer whirlpool beam that disappears was set, the head loss of regulating weir well slightly increased, and the head loss coefficient of wherein high overflow weir regulating weir well increases 0.12, and the head loss coefficient of low overflow weir regulating weir well increases 0.15.

Overflow weir downstream (being the overflow weir back side) is provided with the two-layer whirlpool beam that disappears, the Changing Pattern that floods coefficient is basic consistent with scheme among the embodiment two, and more smaller under identical degree of flooding situation, this with the two-layer whirlpool beam that disappears be set cause that the head loss of weir well has the conclusion of increase to coincide slightly.The overflow weir downstream is provided with the two-layer whirlpool beam that disappears, and the conveyance capacity that (has drop) during to free weir flow is without any influence, and the conveyance capacity when flooding weir flow can slightly reduce.

Three different flow-speed measurement cross-sectional flows distribute more approaching, the velocity flow profile heterogeneous system number average of each section is less than 1.23, be starkly lower than the scheme among the embodiment three, illustrate and be provided with after the two-layer whirlpool beam that disappears, lower floor disappears the whirlpool beam near the box culvert import, help suppressing revolving of overflow weir downstream current and roll, play certain smooth-going flow action, make the velocity flow profile of section S1 also relatively more even; Well flow-speed measurement section S3 farthest in distance adjustment weir is not subjected to the influence of overflow weir downstream fluidised form substantially, near full-blown turbulent flow velocity flow profile.

Calculate by total flow mean allocation in box culvert three holes, the distribution ratio that each orifice flow amount accounts for total flow should be 33.3%.Different in flow rate is measured on the section, and the deviation of the ratio 33.3% when the assignment of traffic ratio in each orifice flow road of actual measurement and flow uniform distribution all is no more than 2%, and the assignment of traffic of each runner is more even.

Under different flows, water level operation combination condition, in the fluidised form observation experiment model of above-mentioned two schemes of low overflow weir and high overflow weir regulating weir well, the bubble that the overflow weir downstream produces, the overwhelming majority is all overflowed in the well of weir, residual bubble enters the downstream the pressure box culvert, air-breathing whirlpool all do not occur in two schemes.

Embodiment five:

Present embodiment is the improvement of embodiment two, is the refinement of embodiment two, as shown in Figure 7.Between the overflow weir of the described regulating weir well of present embodiment and the outlet breastwork wave absorption plate 14 is set, described wave absorption plate cross-arm is between both walls, the upper end of wave absorption plate is concordant with the vertical shaft well head, the lower end of wave absorption plate and the bottom hole spacing of vertical shaft are not less than the height of weir well delivery port, when the distance at the center of wave absorption plate to overflow weir center is not less than minimum operation flow, overflow weir top overflow falls distance and adds hydraulic jump length, and wave absorption plate center to the distance that exports breastwork is not less than 2.5 times hydraulic jump length.

Present embodiment solve deposit in the described regulating weir well of the foregoing description also the problem that water level fluctuation is big, bubble enters pressure conduit.Addressing this problem direct, the simplest way is, increases overflow weir downstream length, and this length is enough to make bubble to be overflowed naturally.Through initial analysis, it is bigger to need to increase length, though the also corresponding increase of the area of regulating weir well can make the water level fluctuation degree reduce, and, engineering quantity and investment significantly increase.Given this, must take compulsory measure.Analyze after deliberation, determine downstream, proper extension weir length, and one cross wall (or claiming the wave absorption plate) is set, make it both suppress water level fluctuation, stop that again bubble is overflowed bubble in advance, avoid entering pressure conduit, have the effect that kills two birds with one stone.Arrange with respect to engineering among the embodiment four, be equivalent to before the pressure conduit import, increase by one section open channel section.

Embodiment six:

Present embodiment is the improvement of embodiment five, is the refinement of embodiment five, as shown in Figure 8.Two rows respectively are provided with 4 to 5 bar-shaped column types whirlpool beam that disappears between the overflow weir of the described regulating weir well of present embodiment and the wave absorption plate, the described whirlpool beam cross-arm that disappears is between both walls, next row whirlpool beam that disappears is horizontal arc horizontally-arranged, be provided with and highly be lower than the overflow weir crest, last row's whirlpool beam that disappears is the horizontal linear horizontally-arranged, is provided with highly to be higher than the overflow weir crest; The wave absorption plate is provided with two rows the whirlpool beam that disappears that 5 to 7 bar-shaped cross sections are rectangle respectively is set to exporting breastwork, bar-shaped cross section be rectangle the whirlpool beam 1203 that disappears two rows be provided with highly respectively identical with the bar-shaped column type of the two rows whirlpool beam that disappears.

The disappear setting of whirlpool beam of wave absorption plate and energy dissipating: for making open channel section water level and stability of flow, preventing that bubble from entering pressure conduit, the wave absorption plate is set between overflow weir and pressure conduit, the main effect of wave absorption plate is to suppress water level fluctuation; Change flow-shape, shorten the bubble flow process, bubble is overflowed in advance.Be effect effective, that give full play to the wave absorption plate, weir center to center distance wave absorption plate centre distance L2 should be less than or equal to l ₁+ l ₂For reducing the head loss of regulating weir well as far as possible, and make regulating weir well overcurrent steady, should be not more than the height of downstream line at the bottom of the wave absorption plate apart from the distance of regulating weir shaft bottom plate.

Surperficial whirlpool takes place in pressure conduit water inlet leading edge waters is general phenomenon comparatively, the surface whirlpool does not have bigger influence to water inlet or the operation of rear tube road, but under normal utilization condition, should avoid producing the through funnel whirlpool of harm pressure pipeline safety operating, it might suck air, makes pipe vibration, flow reduces, increase head loss, influence the performance of engineering safety and benefit, therefore must be avoided.

In the regulating weir well, cross sluice stream at the velocity vector at wave absorption plate, pressure pipeline import breastwork place respectively to two sideway swivels, form on the surface and to reflux, with the current acting in conjunction that flows downward, form vertical shaft whirlpool phenomenon.The integrated structure factor is provided with the cross binding beam respectively before the well section wave absorption plate of weir, before the import of open channel section pressure pipeline, the arrangement form of the whirlpool beam that disappears shown in the figure (elevation, level interval) is suitable for the depth of water and changes big situation, also helps engineering construction.The whirlpool beam that disappears before the wave absorption plate plays energy dissipating, homogenizing current and the whirlpool effect that disappears simultaneously, particularly during low discharge, crosses sluice stream by the disappearing during the beam of whirlpool of low elevation place, and current clash into the whirlpool beam that disappears, thereby reach the purpose of energy dissipating; The whirlpool beam is horizontal arrangement and spacing is less owing to disappear, and makes current comparatively even; Fluidised form before the whirlpool beam forcibly changing import that disappears at rear portion, make current not possess the fringe conditions that forms the vertical shaft whirlpool, thereby reach the purpose in the whirlpool that disappears, can avoid like this producing and hold the gas whirlpool under the arm and carry it into the open channel section at wave absorption plate place, otherwise, when the wave absorption plate is overflowed bubble in advance, produced new bubble again, the wave absorption plate resistance retaining bubble of designing institute expectation and the effect that makes it to overflow have not in advance just had practical significance.The whirlpool beam that disappears before the import of open channel section pressure pipeline only plays the homogenizing current and the whirlpool that disappears, and it prevents to produce the most directly, effectively holds the gas whirlpool under the arm, avoids bubble to enter pressure conduit, and concrete principle is the same.

Prove that through hydraulic model test regulating weir well total length and wave absorption plate and energy dissipating disappear the arrangement form of whirlpool beam and size all relatively rationally, meet design requirement, and show that engineering layout, form of structure and method for designing are scientific and reasonable.

The power control of the described regulating weir well water of present embodiment and protective capacities and principle:

In engineering design, designing unit guarantee that engineering safety is reliable, traffic control simply reaches engineering management easily under the principle, operating condition, influence factor and influence degree thereof that engineering may exist are carried out a large amount of analytic demonstrations, and then comparatively detailed traffic control rule and the control criterion of formulation, such as the control of water-filling flow, amplitude and speed, maintenance operating mode and the condition etc. of flow increase and decrease, engineering management unit implements operation and management according to this Codes and Standards.

For gravity the pressure aqueduct is arranged, after engineering construction is finished, before the formal water flowing operation, should make whole pipe be full of water.For the middle or terminal situation of establishing control valve of traditional pipeline, the unlatching of control valve, help discharging unexpected superpressure, but excessive discharging water can increase the filling time, so the switch of terminal valve and open degree need to change in good time, generally need to carry out all fronts, the analysis of overall process Study on Numerical Simulation, formulate comparatively strict water-filling rule in conjunction with the aqueduct discrepancy in elevation, apart from the factors such as performance of length, arrangement form, pipe stream form and the various annexes of pipeline.Because in the water filling process, flow parameters such as flow velocity, pressure, fluidised form are in the change procedure, unexpected influence factor is a lot, in the actual water filling process, need expend great amount of manpower and material resources and time, also easily because of controlling improper having an accident.And adopt present embodiment described have a regulating weir well the pressure water-carriage system arranged, then make the water-filling problem become very simple, only need pipe water mouth place to control the water-filling flow well, can realize implementing fully automatically, get final product up to pipeline exit overflow weir generation overflow, both make water filling process easy greatly, can guarantee engineering safety again.After pipeline is full of, just can increase the flow of water inlet on request, enter normal operation condition.

Low discharge operating condition can be divided into two kinds, and the one, build up the initial stage in engineering, water user's water requirement is little, does not reach design scale, or because other factors, engineering is in low discharge operating condition always; The 2nd, in the water delivery process, the water delivery flow changes, and is become the situation of low discharge by big flow.For first kind of situation, flow parameters such as flow, flow velocity, pressure are in invariant state in the pipeline, and pipeline is in more stable and constant water delivery state.During the low discharge operation, regulating weir well place current produce and fall, and flow is more little, fall poor big more, though produce the submerged hydraulic jump, help eliminating energy, still have complementary energy, cause water level fluctuation bigger, like this, the depth of immersion of pressure conduit import department just might can not get effective assurance.Such as, requiring depth of immersion during fixed level is 1.5 meters, if the water level fluctuation amplitude is 0.6 meter, then depth of immersion becomes 1.2 meters, does not meet the demands.For the complementary energy of eliminating hydraulic jump can be provided with the wave absorption plate, after being set, the wave absorption plate can reduce water level fluctuation amplitude and degree greatly, and the water level fluctuation amplitude maximum value behind the wave absorption plate only is 5 centimetres.For second kind of situation, because all being in, regulate in the progressive formation flow parameters such as pipeline flow along the line, flow velocity, pressure, if do not take measures, the water level fluctuation situation is more serious, even the transition between free and pressure flow problem occurs.In addition, during ducted a certain segment pipe, need close Emergency Gate, in the independent a certain hole of maintenance because equipment itself reaches other each side factors, shutdown rate can not be very slow, this moment, changes in flow rate speed was bigger, thereby caused the bigger variations of all corresponding generation of flow parameter such as pipeline flow along the line, flow velocity, pressure, and pipeline is imported and exported and the pipeline stem produces bigger water level fluctuation, bright flowing full phenomenon takes place when serious, very negative pressure appears in the person, produces the column separation phenomenon, has a strong impact on engineering safety.Because the wave absorption plate suppresses the effect of fluctuation, and the connection of weir well section and open channel section, weir well section and open channel section fellowship pressure are regulated, regulating power is obviously strengthened, and can avoid the generation of above-mentioned harm.

In actual motion, changes in flow rate is comparatively common, is recurrent, adopts present embodiment can guarantee that traffic control is simple and convenient, guarantees engineering safety.As for the maintenance operating mode, in the actual engineering, generally be to be undertaken by predetermined repair schedule and condition, take the measure of regulating weir well, can be than long pipeline more flexible maintenance condition and mode is provided, also can be applicable to the unintended emergency accident conditions.

Along with the increase of water delivery flow, the overflow weir level of tail water increases, and current fall difference and diminish, and we can say that also the unnecessary head that needs the regulating weir well to eliminate diminishes.Since the increase of the overflow weir level of tail water, the corresponding increase of the water cushion degree of depth, hydraulic jump degree of flooding further increases, and energy dissipation rate further improves, and water level fluctuation is littler, and bubbles volume is still less.Also increase just because of water level, current horizontal direction flow velocity is very little in the well of weir, and bubble is in the effusion process, and the flow process of Parallel to the flow direction becomes shorter, the very fast effusion water surface of bubble.In addition, the water cushion degree of depth is big more, and the wave absorption plate is more little to the ratio of the aperture height of regulating weir shaft bottom plate and the depth of water, and be equivalent to aperture height and diminish, the inhibition fluctuation of wave absorption plate and stop that the effect of bubble is strong more, effect is obvious more.When flow increased to design scale, current flow through in the overflow weir upper horizontal, and the overflow weir water levels of upstream and downstream remains basically stable, and did not have current to fall phenomenon, did not also just have the problem that produces bubble because of drop; And the overflow weir top depth of water is bigger, and the volume of whole regulating weir well is bigger, and flow-shape is the most steady.At this moment, pipeline has utilized the water delivery of pipe ends maximal head difference, does not have unnecessary head, does not need the regulating weir well to eliminate head, and current just simply flow through the regulating weir well.

Before stopping water delivery, should reduce the flow of conduit entrance place by operation rule, when reducing to the predetermined running flow, close entrance gate by the operating gate rules, the vanishing of conduit entrance place flow is because the effect of inertia of current, water body is still flowing in the pipeline, and flow parameter all is in the change procedure.Flow in the well of weir, upstream at first diminishes, overflow weir upstream and downstream water level diminishes, the weir upper pond level moves closer to weir crest, until equaling the weir crest elevation, the corresponding discharge vanishing, because overflow weir weir crest elevation is higher than upstream line import certain distance, make the interior water body of pipeline still be kept in the pipeline, promptly water body is slack in the pipeline.Because the regulating weir well is regulated the effect of head automatically, the pipeline fluidised form is regulated automatically gradually downstream from the upstream and is adapted to, and water body is tending towards stopping in the process at one stably gradually, automatically in the pipeline.Because the existence of regulating weir well except that the operation inlet gate, need not operated pipeline any facility along the line, just can cut off the water automatically, not only simply but also reliable.

Because the downstream weir crest of pipeline is all above crest level in this segment pipe top between each regulating weir well, make pressure conduit when stopping water delivery, still keep full water state, thereby the problem of pressure conduit water-filling when having avoided next recovery water delivery, only needing to open the pipeline inlet gate gets final product, the water body nature is by automatic stream downstream, upstream, need not operate pipeline any facility along the line equally, with regard to automatically starting operation, not only simply but also reliable.

When the low discharge water delivery, the drop phenomenon takes place in the overflow weir place, for guaranteeing the reliable water delivery of engineering safety, should fully eliminate down the stream energy in the generation of holding under the arm that sluices.Owing to be provided with many regulating weir wells along the line, make each overflow weir downstream that the water cushion of certain depth all be arranged, the water cushion degree of depth is greater than the back section depth of water (being also referred to as conjugate depth) that jumps of drop hydraulic jump, form submerged hydraulic jump, help energy dissipating like this, need not establish absorption basin and energy dissipater, not only make fluidised form simple, and can save engineering quantity and maintenance workload in the future.Flow is big more, and water cushion is dark more, and degree of flooding is big more, can improve the hydraulic jump performance more, reduce water level fluctuation, and hydraulic test fully proves this point, as shown in Figure 7.

When making low discharge open channel section water level and stability of flow, prevent that bubble from entering pressure conduit, the wave absorption plate is set between overflow weir and pressure conduit, form a pressure down-the-hole between wave absorption plate and the regulating weir shaft bottom plate, must be through the current of letting out under the overflow weir through this pressure down-the-hole, the pressure down-the-hole plays wave filter, simultaneously, open channel section area is bigger, and the effect of this two aspect all reduces water level fluctuation amplitude, degree greatly.Underwater bubble, because the effect of buoyancy and flow rate of water flow is parabolic and rises in water, flow rate of water flow is big more, and bubble pathway length is big more, and the depth of water is big more, and bubble pathway length is big more, and required building length is big more.The setting of wave absorption plate has changed the motion of air bubbles track, and bubble straight line under the stopping of wave absorption plate is risen, and has reduced the stroke of bubble greatly, like this, has both prevented that bubble from entering pressure conduit, can effectively shorten the length of building again.See Fig. 9, Figure 10 for details.

The regulating weir well has in the water-carriage system of pressure at gravity, each self-applying of weir well section, wave absorption plate and open channel section is not fully exerted, and mutually combine to each other, adapt to, make the regulating weir well have multiple usefulness and resultant effect, make the function and the superiority of regulating weir well be further enhanced, enlarge and enrich, essence, critical guarantee effect are played in long waterpower control and protection apart from the pressurized water transmission system.

Because the volume of regulating weir well is bigger, the effect of the effect of its surge shaft, elimination issuable water hammer pressure in service not only further be enhanced, and each regulating weir well is equivalent to a balancing tank, can guarantee that the upstream and downstream flow cooperates and adjusting.

Regulating weir well by the ladder setting, unsteady flow fluctuation is controlled effectively, has realized in the engineering scheduling utilization process adaptivity of unsteady flow has been reduced artificial, mechanically actuated, engineering scheduling utilization and management have greatly been made things convenient for, the safety that has improved engineering.

The hydraulic test that present embodiment carries out is identical with the described test of the foregoing description at test method, instrument setting and terms and conditions thereof with the hydraulic test that the foregoing description is carried out, and has only revised test model, has promptly increased the open channel section, the whirlpool beam that disappears in the open channel section.No matter the regulating weir well is free weir flow, floods weir flow, be provided with weir, downstream well after the open channel section fluidised form be improved significantly, there is the flow velocity of pressing the box culvert import in the downstream near distributing uniformly.Through test as can be known, after the overflow weir downstream was provided with the open channel section, the downstream has pressed near the current of box culvert import to revert to equal uniform flow fluidised form substantially.

Calculate by total flow mean allocation in box culvert three holes, the distribution ratio that each orifice flow amount accounts for total flow should be 33.3%.Under the different service conditions, the maximum deviation of the ratio 33.3% when the assignment of traffic ratio in each orifice flow road of actual measurement and flow uniform distribution all is no more than 1.5%, shows that the assignment of traffic of each runner is more even.

Experimental data shows: after regulating weir well downstream is provided with the open channel section, open channel section water-level fluctuation amplitude all is significantly less than the water-level fluctuation amplitude of weir, the scheme downstream well of not establishing the open channel section under each typical operation condition, though from fluidised form, the open channel section exists than significantly gushing and backflow phenomenon on the current under the part operating mode, but under each operating condition of test in the open channel section water surface all more steady generally, fluctuating range is very little, all is no more than 5cm.

When downstream, weir relative water depth greater than 1.4 the time, high overflow weir regulating weir well gross head loss coefficient is approximate to level off to a constant 3.09, low overflow weir regulating weir well gross head loss coefficient is approximate to level off to a constant 3.40; The high overflow weir regulating weir well scheme gross head loss coefficient of no open channel section is approximate in the previous embodiment levels off to a constant 2.43, and the low overflow weir regulating weir well scheme gross head loss coefficient of no open channel section is similar to and levels off to a constant 3.13 in the previous embodiment.Therefore, after the open channel section was set up in the overflow weir downstream, the gross head loss coefficient of high overflow weir and low overflow weir regulating weir well increased to some extent, and the head loss value increases, but the head loss value added of single seat regulating weir well all is no more than 3.7cm.

In the test, the open channel segment length in high overflow weir and the low overflow weir regulating weir well is shortened 0.5m, 1.0m, 1.5m and 2.0m respectively, under difference operation flow, observed fluidised form wherein.When the operation flow is 20m ³/ s～30m ³During/s, the open channel segment length shortens 0.5m, 1.0m, and the fluidised form difference is not obvious.When shortening 1.5m, can estimate the fluidised form difference; When shortening 2.0m, the fluidised form difference is obvious gradually, can be observed that the water surface in the open channel section refluxes and water body on emerge in large numbers and resemble all reinforcement to some extent.Flow increases to 40m ³During/s, during contraction in length 0.5m, just can estimate the difference of fluidised form; Contraction in length 1.0m, the fluidised form difference begins that other is obvious; Emerge in large numbers on contraction in length 1.5m backflow and the water body and resemble obvious reinforcement.At the operation flow is 50m ³/ s～60m ³/ s, when the open channel segment length shortened 0.5m, just energy observe to emerge in large numbers on backflow and the water body more clearlyly and resemble obvious reinforcement.Above-mentioned phenomenon shows: the length of the open channel section in described high overflow weir of present embodiment and the low overflow weir regulating weir well is suitable, should not further shorten again.

The foregoing description and present embodiment described overflow weir position and overflow weir weir crest elevation (height of overflow weir) are tested, and result of the test is as follows:

(1) overflow weir position

For the influence of the position of analyzing overflow weir to the regulating weir well, the overflow weir position is moved downstream, the aboveground trip lateral extent of overflow weir is doubled.

At regulating weir well weir body downstream behind the side shifting 4.4m, length increase because of weir, upstream well, it is smooth-going that streamline is tending towards, conveyance capacity slightly increases, therefore, discharge coefficient increases, and high overflow weir regulating weir well yield coefficient increases 0.013, low overflow weir regulating weir well yield coefficient increases 0.009, but the relative amplitude that discharge coefficient increases all is no more than 2.5%.

When downstream, weir relative water depth greater than 1.4 the time, high overflow weir regulating weir well gross head loss coefficient is approximate to level off to a constant 2.55, low overflow weir regulating weir well gross head loss coefficient is approximate to level off to a constant 2.76; Level off to a constant 3.09 and the former scheme gross head of high overflow weir regulating weir well loss coefficient is approximate, the low former scheme gross head of overflow weir regulating weir well loss coefficient is approximate to level off to a constant 3.40.Therefore, in regulating weir Jing Yan body position downstream behind the side shifting 4.4m, because of the length of weir, upstream well increases, it is smooth-going that streamline is tending towards, and the head loss coefficient reduces, but the amplitude that reduces is less than 1.0.At the water delivery flow is 60m ³During/s (maximum stream flow), the amplitude that the head loss of single seat regulating weir well reduces is no more than 3.6cm.

Above-mentioned test result shows, the body position, weir is downstream after the side shifting, because of the length of weir, upstream well increases, it is smooth-going that streamline is tending towards, and discharge coefficient increases to some extent, and the head loss coefficient reduces to some extent, but the improvement amplitude is not remarkable, and this shows that original layout thinking and principle of determining is rational.When, engineering gross head more when regulating weir well seat number is nervous and valuable, can be optimized layout with reference to this thinking.

(2) overflow weir weir crest elevation

In actual engineering, rationally definite existing certain science of overflow weir weir crest elevation is again a key link.Say that it has certain science, the factor that is meant the definite weir crest elevation of influence is more, and must make that overflow weir head loss when big flow is little, can guarantee the pressure that safe operation is required in the time of really effectively regulating head, minimum operation flow automatically during low discharge, need take all factors into consideration and could determine.Saying that it is a key link, mainly is because it is concerning that not only can engineering safe operation, but also influence construction investment, such as, when cutting off the water, import and export the requirement of degree of flooding by pressure conduit and determine buried depth of pipeline, like this, can guarantee that pipeline all can satisfy degree of flooding requirement under any flow, but, this is too conservative, causes construction investment bigger, moreover also there is no need, the engineering distance is long more, and the influence investment is big more.Given this, should under the condition that guarantees the engineering safety operation, raise the weir crest elevation as far as possible,, save construction investment to reduce buried depth of pipeline.

In order to analyze the influence of weir crest elevation, the height of weir of high overflow weir, low overflow weir regulating weir well is increased 1.0m, all the other layouts are all constant, the discharge coefficient of high overflow weir and low overflow weir regulating weir well all increases to some extent, high overflow weir regulating weir well yield coefficient increases 0.010, low overflow weir regulating weir well yield coefficient increases 0.003, but the relative amplitude that discharge coefficient increases is very little.

When downstream, weir relative water depth greater than 1.4 the time, when just reaching design scale, high overflow weir regulating weir well increases that scheme gross head loss coefficient is approximate to level off to a constant 3.70, and low overflow weir regulating weir well increases that scheme gross head loss coefficient is approximate to level off to a constant 4.24; Level off to a constant 3.09 and the high former scheme of overflow weir regulating weir well (when overflow weir does not increase) gross head loss coefficient is approximate, the low former scheme of overflow weir regulating weir well (when overflow weir does not increase) gross head loss coefficient is approximate to level off to a constant 3.40.That is to say that after regulating weir well height of weir increased 1.0m, head loss coefficient and head loss increased little, head loss increases 0.034m and 0.047m respectively, and head loss coefficient value added is all less than 1.0.

The head loss of pressure conduit water delivery engineering comprises two kinds of frictional head loss and local head losses, the gravity current water delivery engineering is exactly to utilize the discrepancy in elevation of pipe ends to overcome the water delivery of these two loss ability, principle during design is exactly, when design discharge, the discrepancy in elevation of pipe ends equals the frictional head loss and the local head loss of pipeline.Apart from the pressure conduit water delivery engineering, the local head loss of all kinds of buildings proportion in total losses is very little, is generally 5%, ignores in the engineering that has for long.In the present embodiment, the height of weir of overflow weir has been increased by one meter, the amplitude of increase is bigger, and still, local head loss increases but very limited, this just for reduce buried depth of pipeline, save that construction investment provides reliably, basis science, sufficient and guarantee.

In experimental study, for reliability, objectivity and the representativeness of guarantee test achievement, in physical experiments, chosen two representational regulating weir wells and carried out system test, and the works limit of simulation is also longer.Simultaneously, in order to verify the reasonable reliability of every regulating weir well and whole engineering system, also carried out the Study on Numerical Simulation of various possible operation conditions, studies show that, the engineering of regulating weir well is arranged and the thinking and the principle of design are scientific and reasonable, safe and reliable, is abundant engineering demands.

It should be noted that at last, below only unrestricted in order to technical scheme of the present invention to be described, although the present invention is had been described in detail with reference to the preferred arrangement scheme, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention (such as the profile of the vertical shaft of regulating weir well, overflow weir, wave absorption plate, size, arrangement etc.), and not break away from the spirit and scope of technical solution of the present invention.

Claims (6)

1. a gravity that has automatic regulating weir well has the pressure water-carriage system, described system comprises: the upstream water delivery water inlet and the downstream water delivery delivery port that is arranged on water side that are arranged on water supply side, it is characterized in that, be connected at least one regulating weir well by pipeline between described water delivery water inlet and the water delivery delivery port, described regulating weir well comprises: the weir well water inlet bottom the import breastwork of regulating weir well that is connected with upstream line, described import breastwork both sides connect weir well side wall respectively, what be connected with described weir well side wall is the outlet breastwork of regulating weir well, and the bottom of described outlet breastwork is the weir well delivery port that is connected with the downstream aqueduct; It is the vertical shaft of the regulating weir well of rectangle that import breastwork, outlet breastwork, two side weir Jing Qiang form the cross section, the well head on described vertical shaft top opens wide or covers the overburden that air can flow, overflow weir is arranged at the silo bottom between import breastwork and the outlet breastwork, and cross-arm is between both walls.

2. system according to claim 1, it is characterized in that, the overflow weir cross section of described regulating weir well is the broken line practical weir type of cavetto, described import breastwork to the distance at overflow weir center is not less than weir well water inlet height, the height of described overflow weir is: during minimum operation flow, weir well water inlet depth of immersion is not less than 1.0 meters, weir well outlet depth of immersion is not less than 1.5 meters, the overflow weir crest to the height of the well head of regulating weir well more than or equal to weir well water inlet height, described overflow weir center is when exporting distance between the breastwork and be not less than minimum operation flow, overflow weir top overflow falls distance and adds hydraulic jump length, adds 2.5 times hydraulic jump length again.

3. system according to claim 2, it is characterized in that, between the overflow weir of described regulating weir well and the outlet breastwork absorption basin is set, at described absorption basin upper horizontal arc horizontally-arranged 3 to 4 whirlpool beams that disappear are set, the described whirlpool beam that disappears be bar-shaped cylinder cross-arm between both walls, highly be higher than the overflow weir crest.

4. system according to claim 2, it is characterized in that, two rows respectively are provided with 4 to 5 bar-shaped column types whirlpool beam that disappears between the overflow weir of described regulating weir well and the outlet breastwork, the described whirlpool beam cross-arm that disappears is between both walls, next row whirlpool beam that disappears is horizontal arc horizontally-arranged, be provided with and highly be lower than the overflow weir crest, the last row whirlpool beam that disappears is the horizontal linear horizontally-arranged, is provided with highly to be higher than the overflow weir crest.

5. system according to claim 2, it is characterized in that, between the overflow weir of described regulating weir well and the outlet breastwork wave absorption plate is set, described wave absorption plate cross-arm is between both walls, the upper end of wave absorption plate is concordant with the vertical shaft well head, the lower end of wave absorption plate and the bottom hole spacing of vertical shaft are not less than the height of weir well delivery port, when the distance at the center of wave absorption plate to overflow weir center is not less than minimum operation flow, overflow weir top overflow falls distance and adds hydraulic jump length, and wave absorption plate center to the distance that exports breastwork is not less than 2.5 times hydraulic jump length.

6. system according to claim 5, it is characterized in that, two rows respectively are provided with 4 to 5 bar-shaped column types whirlpool beam that disappears between the overflow weir of described regulating weir well and the wave absorption plate, the described whirlpool beam cross-arm that disappears is between both walls, next row whirlpool beam that disappears is horizontal arc horizontally-arranged, be provided with and highly be lower than the overflow weir crest, the last row whirlpool beam that disappears is the horizontal linear horizontally-arranged, is provided with highly to be higher than the overflow weir crest; Wave absorption plate center is provided with two rows the whirlpool beam that disappears that 5 to 7 bar-shaped cross sections are rectangle respectively is set to exporting breastwork, bar-shaped cross section be rectangle the whirlpool beam that disappears two rows be provided with highly respectively identical with the bar-shaped column type of the two rows whirlpool beam that disappears.

Images