CN100347378C - Self aeration method for sidewall of construction for releasing water in high velocity of flow - Google Patents
Self aeration method for sidewall of construction for releasing water in high velocity of flow Download PDFInfo
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- CN100347378C CN100347378C CNB2005100869200A CN200510086920A CN100347378C CN 100347378 C CN100347378 C CN 100347378C CN B2005100869200 A CNB2005100869200 A CN B2005100869200A CN 200510086920 A CN200510086920 A CN 200510086920A CN 100347378 C CN100347378 C CN 100347378C
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Abstract
The present invention relates to a self aeration method for a sidewall of a water release structure at a flow velocity, which belongs to the technical field of protection of the sidewall of the water release structure, particularly, the technical field of preventing cavitation erosion and destruction to the sidewall of the water release structure at a high flow velocity. The present invention is characterized in that the sidewall of the water release structure at a high flow velocity is provided with a slope-shaped side flip bucket along the direction of the water flow; a row of air mixing holes are arranged below the side flip bucket on the side wall; an aeration pipe communicated with the air mixing holes is arranged on the back part of the sidewall. The side flip bucket is divided into two types of a continuous type and a differential type. The implement of the method can form air mixing water flow with large ranges and high concentration near the sidewall so as to effectively protect the sidewall and to reduce the danger of damage of cavitation and cavitation erosion to the sidewall of the water release structure at a high flow velocity.
Description
Technical field:
Self aeration method for sidewall of construction for releasing water in high velocity of flow belongs to outlet structure escape works side wall protection technical field, particularly prevents the technical field of sidewall of construction for releasing water in high velocity of flow cavitation erosion.
Background technology:
Along with the raising of dam construction technique and the fast development of China's water resources and hydropower construction cause, high water head, big flow outlet structure escape works constantly increase, and a collection of height of dam will build up successively in the huge hydroelectric project (as voe, Xi Luodu, silk screen one-level etc.) of superelevation dam and the ultrahigh speed current of 200～300m.Exceed most flow velocity Du Keda 50m/s in the high water head outlet structure escape works such as the flood discharging tunnel of these engineerings, deep hole and flood spillway.Consequent high-velocity flow problem becomes increasingly conspicuous, and the possibility that serious cavitation erosion takes place outlet structure escape works increases gradually, becomes one of restraining factors of high dam design, construction, thereby enjoys engineering circle and researcher's concern.
At present, for the protection of high water head flood discharging tunnel cavitation erosion, only adopt to guarantee the wall planeness and use the method for anti-cavitation corrosion material can not finely to meet the demands, facts have proved: air mixing corrosion reducing is the effective means that prevents cavitation erosion.Existing experimental study shows, when the aeration concentrater C=1% of near wall place in the water～2%, can obviously alleviate the cavitation erosion of solid-surface; When aeration concentrater reaches C=5%～7%, but the cavitation erosion complete obiteration.In recent years for the existing a lot of achievements in research of air mixing corrosion reducing, under chute, flood spillway, flood discharging tunnel, lock, gone out in the high water head outlet structure escape works such as stream, vertical shaft to be used widely, and obtained howling success, a large amount of engineering practices show that the air mixing corrosion reducing facility can make the base plate of outlet structure escape works be subjected to excellent protection; But, near the side wall of Spillway Tunnel downstream, some comparatively serious destruction examples have still appearred in the spilled water hole side wall part that sudden enlargement and sudden is arranged, be provided with 8 bottom outlets as former Soviet Union Peter Krass Nuo Yaersike power station, put into operation in 1967, operating head polishing is 0～60m, and nineteen sixty-eight is checked and finds falling on the sidewall of bank downstream near the jet root edge of 4,5, No. 8 holes cavitation erosion to take place; The Longyangxia Hydroelectric Power Station bottom outlet began utilization in 1987, moved altogether 3 times to 1989, and total water of crossing lasts 7137 hours, aperture the highest utilization head 89m.News back in 1989 checks and finds apart from falling about 37m place, bank downstream, side wall destruction seriously, the dark 2.5m of favourable opposition of leftwall, damage area 180m
2, the dark 0.7m of favourable opposition of RightWall, damage area 104m
2, destroy former because the cavitation erosion that current aeration deficiency causes; U.S. De Woxieke dam also is the typical case of side wall cavitation erosion, three spilled water holes all adopt sudden enlargement and sudden to arrange, design head 81m, port size 2.7m * 3.8m, the section Peak Flow Rate 38m/s of Service gate place, after spilled water hole sluiced one month, cavitation erosion has in various degree all taken place in three spilled water holes, wherein, middle and left side spilled water hole destroys comparatively serious, and particularly the cavitation erosion on the abutment wall of the terminal both sides of left side spilled water hole mask is the most serious, and the cavitation erosion head of district reaches 6m, dark 0.56m, high 3m; In addition as the spilled water hole side wall in power station, two beaches 1# flood discharging tunnel, Pakistani Ta Beila power station etc. the different cavitation erosion of degree has all taken place, and along with the increase with flow velocity of increasing of head, the possibility of Spillway Tunnel downstream side wall generation cavitation erosion has the trend of growth.
About how strengthening the side wall protection of high water head outlet structure escape works, improve the research of no concrete build both at home and abroad now of sidewall water flow structure.Cavitation erosion reason at the outlet structure escape works side wall has a small amount of achievement in research,
Existing research is thought, because it is strong that the aeration cavity will obviously reduce the moving hydraulic pressure of cavity top, the end and near side-walls thereof, simultaneously because the interior free aeration of the water surface of this scope still is in developing stage, side wall middle part behind the aerator of bottom will form clear water band (aeration blind area) in a big way, the air entrainment of these zone current is very little, far do not reach the requirement of corrosion inhibitor, only can rely on the resistance to corrosion of control wall irregularity degree and raising wall surface material.And for large-area side wall, construction quality index such as strict control wall irregularity degree is difficulty comparatively, therefore easily produces cavitation erosion.
Existing research only rests on the theory analysis reason stage, does not propose concrete solution.Applicant has been studied the influence of side direction baffler offside cavity and lower cavity aeration parameter once in conjunction with Three Gorges deep hole model testing, has all carried out deeply probing into for problems such as the special flow characteristics of side wall, side wall aeration mechanism.The big proportional model test that the applicant carried out studies show that: form four zones on the side wall, that is: and side cavity zone, pressure drop district, low-pressure area and stable region, position that each is regional and shape all are subjected to the influence of flow rate of water flow.After flow velocity arrives to a certain degree, begin to occur closed negative pressuren zone in the area of low pressure, and along with the increase of flow velocity, move downstream gradually the position of negative pressuren zone, scope constantly increases, negative pressure value constantly raises, and progressively develops into cavitation and bring out the source.Observation finds, at side wall water impact point place, rolls the entrainmenting of air because vertical shaft revolves, and produced a small amount of aeration band, and aeration concentrater is about 1.3%, but the aeration of this concentration still can not satisfy the requirement that prevents cavitation erosion.
The applicant under the subsidy of state natural sciences fund, furtherd investigate the side wall aeration afterwards, had proposed in the new technology of side wall realization from aeration.Should successfully solve this type of problem from the aeration technology by novel side wall air entraining facilities.Confirm through big proportional model test, can improve the side wall aeration concentrater effectively, form side wall aeration urban conservation area widely.
Summary of the invention:
The objective of the invention is to; a kind of self aeration method for sidewall of construction for releasing water in high velocity of flow is proposed; this method is by installing additional from air entraining facilities at high flow rate outlet structure escape works sidewall; near sidewall, form on a large scale, the aerated flow of high concentration; thereby protective side wall effectively, the danger of having reduced or remitted sidewall of construction for releasing water in high velocity of flow generation cavitation destruction.
This method is characterised in that: along the depth of water direction domatic side is set and chooses bank on sidewall of construction for releasing water in high velocity of flow, this side is chosen bank and flow direction quadrature, on described side wall, be positioned at side and choose the bank bottom and have a row aeration hole, a ventilating pipe that communicates with described aeration hole is set at described side wall rear portion.
Described side is chosen bank can only establish a continuous tall and slender bank.
Described side is chosen bank also can be made as slotted flip bucket, is chosen bank and is formed by short more than two, be spaced, and each side is chosen and had an aeration hole under the bank.The distance that sides adjacent is chosen between the bank can equate.The length that side is chosen bank also can equate.
Evidence is chosen bank and offer side aeration hole behind bank installing additional on the sidewall of construction for releasing water in high velocity of flow, and current are flowed through after side chooses bank, can form on a large scale on sidewall, stable negative pressure cavity.Under suction function, outside air enters in the water via side aeration hole, after gas, the abundant blending of water, can form the aerated flow of high concentration near sidewall; And in the quite long distance in downstream, the sidewall current all can keep enough aeration concentraters, thereby have reduced or remitted the danger of sidewall generation cavitation erosion effectively.
Description of drawings:
Fig. 1 is that the continous way side wall is from the air entraining facilities schematic diagram;
Fig. 2 be the continous way side wall from the three-dimensional view that air entraining facilities shows, wherein be the front view that Fig. 2 b is, Fig. 2 a is that the A of Fig. 2 b cuts open figure, Fig. 2 c is the vertical view of Fig. 2 b;
Fig. 3 is that the differential type side wall is from the air entraining facilities schematic diagram;
Fig. 4 be the differential type side wall from the three-dimensional view that air entraining facilities shows, wherein be the front view that Fig. 4 b is, Fig. 4 a is that the A of Fig. 4 b cuts open figure, Fig. 4 c is the vertical view of Fig. 4 b;
Fig. 5 is that the continous way side is chosen bank side wall aeration concentrater distribution curve;
Fig. 6 is that the differential type side is chosen bank side wall aeration concentrater distribution curve.
Among the above-mentioned figure, 1 is side wall, and 2 is the aeration hole, and 3 is ventilating pipe, and 4 choose bank for side, and L represents that side chooses bank length, and arrow is represented water (flow) direction.
The specific embodiment:
Side is chosen bank can be divided into two types of continous way and differential types, though all can reach the purpose of air mixing corrosion reducing protection side wall, both the caused flow-shapes and the aeration concentrater regularity of distribution have different characteristic.
The continous way side is chosen bank as depicted in figs. 1 and 2, only establishes a side and choose bank 4 on side wall 1, and length L is longer, and choosing bank in side has a row aeration hole 2 for 4 times, communicates with ventilating pipe 3 behind the side wall 1.Under the operating mode of continuous flip bucket, current are flowed through after side chooses bank, to inner flip shot, are separated from wall, and through behind the certain distance, wall again can fall back.In this section zone, can form a nearly wall cavity of sealing, certain-length up and down; Outside air enters cavity by the aeration hole that is located at behind the bank, and on gas, water engaging surface blending takes place, and forms certain aeration concentrater.When aerated water was wandered back wall, (being the cavity end) formed revolving of a white and rolls band at the place of penetrating that falls, and also can form good gas, water blending.Thereafter bubble is overflowed gradually, and aeration concentrater progressively descends.
The differential type side is chosen bank as shown in Figure 3 and Figure 4, is provided with a plurality of sides and chooses bank 4 on side wall 1, and length L is shorter, and each side is chosen bank an aeration hole 2 for 4 times, communicates with ventilating pipe 3 behind the side wall 1.Under the operating mode of slotted flip bucket, the part current flow through from choosing bank, and the part current flow through from the gap that segmentation is chosen between the bank.Under this operating mode, the flip shot effect of slotted flip bucket can not make the sidewall current break away from wall on a large scale, form cavity, but forms one long and narrow air inlet band after choosing bank.Sidewall surfaces, some parallel air inlet bands constantly turbulent fluctuation, fragmentations in current develop into large-scale gas, water blending zone, form quite high aeration concentrater in nearly wall current, and extend to the downstream.The differential type side is chosen bank and can equidistantly be arranged.Compare with continous way, its total air entrainment is bigger.
By model testing, measured the nearly wall Air Concentration in Water Flow under two kinds of operating modes of continous way and differential type, as shown in table 1:
Table 1 sidewall Air Concentration in Water Flow (%)
| Measuring point and side are chosen the distance/mm of bank | Continuous flip bucket | Slotted flip bucket | |||
| 2.0m head | 2.5m head | 2.0m head | 2.5m head | 2.9m head | |
| 69 | 80.18 | 81.35 | 42.67 | 42.57 | 44.29 |
| 229 | 71.87 | 63.43 | 41.47 | 35.73 | 38.19 |
| 451 | 84.92 | 84.98 | 25.44 | 27.13 | 31.19 |
| 644 | 83.24 | 86.61 | 26.19 | 24.91 | 26.20 |
| 914 | 12.65 | 64.78 | 5.22 | 5.75 | 3.38 |
| 1197 | 5.13 | 59.24 | 4.89 | 9.03 | 11.42 |
| 1459 | 1.89 | 3.44 | 4.69 | 5.86 | 7.33 |
| 1794 | 3.88 | 3.10 | 5.81 | 5.31 | 6.92 |
As shown in Figure 5, the continous way side is chosen under the bank operating mode, and the front portion of aeration concentrater curve is often up to more than 80%; This part is not an aerated flow, but side is chosen the nearly wall side cavity zone that current behind the bank break away from the formed curtain shape of wall, and the 1.5-2 that this regional length is about cavity length of the general end doubly.In this aeration curtain,, can form side wall localised protection zone completely because current have broken away from wall.At the end of aeration curtain, i.e. current falling place, can form concentration usually is the aeration band of 10%-20%; Along with the continuous effusion of bubble, the aeration concentrater of the nearly wall current in downstream reduces gradually.
Choose under the operating mode of bank in the differential type side as shown in Figure 6, sidewall does not form large-area nearly wall cavity zone.Near directly turbulent fluctuation blending sidewall of gas, water forms about 30% aeration concentrater.Along with the effusion gradually of bubble, the aeration concentrater of downstream current progressively reduces, but compares with the operating mode that the continous way side is chosen bank, and its downward trend comparatively steadily slowly can keep the aeration concentrater more than 5% in the quite long scope in downstream.In this aeration concentrater scope, can reduce or remit cavitation erosion effectively, the protection side wall.
From flow-shape and aeration concentrater distribution characteristics, the continous way side is chosen bank and is forwardly formed the sidewall cavity, and current break away from wall; The nearly wall current in rear portion can keep certain aeration concentrater, but decay is very fast.It is less to the change of flow-shape that the differential type side is chosen bank, forwardly forms gas, water turbulent fluctuation dilution zone, forms the nearly wall aerated flow of high concentration; Rear portion aeration concentrater decay is slower, the air mixing corrosion reducing concentration that can remain valid in longer zone.Follow border applicable cases and protection purpose factually, the side that can select to suit is chosen the bank form in order to the protection side wall.
Side wall is chosen bank, aeration hole and ventilating pipe etc. from air entraining facilities by side and is partly formed, and the synergy of choosing bank and aeration hole by side reaches the effect of sidewall current from aeration.Be provided with separately that side is chosen bank or the aeration hole is invalid.
Evidence, behind the shutoff side aeration hole, side is chosen bank can not form aerated flow; Remove side and choose bank, then can not form enough negative pressure near the side aeration hole, can not air inlet.Therefore, to choose the synergy in bank and side aeration hole be the key that this novel facility is played effectiveness to side.The position can be according to the applicable cases and the protection purpose of actual engineering; install additional in the upstream, position that sidewall of construction for releasing water in high velocity of flow need be laid special stress on protecting this from the aeration device (as sluice way on the side wall of anti-arc end; sudden enlargement and sudden outgoing current are in the shock point downstream of side wall etc.); can form aerated flow at the nearly wall of side wall place, protection side wall deduction and exemption cavitation erosion.
This technology has solved the problem of high water head outlet structure escape works side wall generation cavitation erosion.Adopt this will protect the side wall of high-velocity flow building effectively, form high aeration concentrater current, avoid the side wall cavitation erosion from the aeration technology.
Claims (5)
1, self aeration method for sidewall of construction for releasing water in high velocity of flow, it is characterized in that, on sidewall of construction for releasing water in high velocity of flow, the domatic side is set and chooses bank along depth of water direction, described side is chosen bank and flow direction quadrature, on described side wall, be positioned at side and choose the bank bottom and have a row aeration hole, a ventilating pipe that communicates with described aeration hole is set at described side wall rear portion.
2, self aeration method for sidewall of construction for releasing water in high velocity of flow as claimed in claim 1 is characterized in that, described side is chosen bank one.
3, self aeration method for sidewall of construction for releasing water in high velocity of flow as claimed in claim 1 is characterized in that, described side is chosen bank to be had more than two, be spaced, and each side is chosen and had an aeration hole under the bank.
4, self aeration method for sidewall of construction for releasing water in high velocity of flow as claimed in claim 3 is characterized in that, the distance that sides adjacent is chosen between the bank equates.
5, self aeration method for sidewall of construction for releasing water in high velocity of flow as claimed in claim 3 is characterized in that, described side is chosen the equal in length of bank.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100869200A CN100347378C (en) | 2005-11-18 | 2005-11-18 | Self aeration method for sidewall of construction for releasing water in high velocity of flow |
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| CNB2005100869200A CN100347378C (en) | 2005-11-18 | 2005-11-18 | Self aeration method for sidewall of construction for releasing water in high velocity of flow |
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| CN1760463A CN1760463A (en) | 2006-04-19 |
| CN100347378C true CN100347378C (en) | 2007-11-07 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101570966B (en) * | 2009-05-27 | 2010-09-01 | 中国水电顾问集团中南勘测设计研究院 | Dispersed ventilated aerator for aerification |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102277862B (en) * | 2011-05-11 | 2013-07-10 | 中国水利水电科学研究院 | Side-wall aeration ramp for free flow tunnel |
| CN103290818B (en) * | 2013-07-01 | 2015-07-15 | 中国电建集团中南勘测设计研究院有限公司 | Structure for inhibiting water flow cavitation of outlet structure |
| CN104775405B (en) * | 2015-03-26 | 2016-06-22 | 中国水利水电科学研究院 | Fall bank disspation through hydraudic jimp and force air mixing corrosion reducing device |
| CN107421846B (en) * | 2017-09-21 | 2023-03-14 | 水利部交通运输部国家能源局南京水利科学研究院 | Negative pressure type aeration concentration instrument and operation method thereof |
| CN112982328A (en) * | 2021-03-12 | 2021-06-18 | 四川大学 | Sudden expansion and sudden drop arc-shaped gate rear wall aeration structure |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU499375A1 (en) * | 1973-07-11 | 1976-01-15 | Научно-Исследовательский Сектор Всесоюзного Ордена Ленина Проектно-Изыскательского И Научно-Исследовательского Института "Гидропроект" Им.С.Я.Жука | Cavitation Elimination Device |
| CN1082648A (en) * | 1993-07-08 | 1994-02-23 | 水利水电科学研究院水力学研究所 | Air mixing corrosion reducing technology for pressure flow |
-
2005
- 2005-11-18 CN CNB2005100869200A patent/CN100347378C/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU499375A1 (en) * | 1973-07-11 | 1976-01-15 | Научно-Исследовательский Сектор Всесоюзного Ордена Ленина Проектно-Изыскательского И Научно-Исследовательского Института "Гидропроект" Им.С.Я.Жука | Cavitation Elimination Device |
| CN1082648A (en) * | 1993-07-08 | 1994-02-23 | 水利水电科学研究院水力学研究所 | Air mixing corrosion reducing technology for pressure flow |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101570966B (en) * | 2009-05-27 | 2010-09-01 | 中国水电顾问集团中南勘测设计研究院 | Dispersed ventilated aerator for aerification |
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