CN106640481A - Method for reducing harm of draft tube eccentric vortex strip of Francis hydraulic turbine - Google Patents
Method for reducing harm of draft tube eccentric vortex strip of Francis hydraulic turbine Download PDFInfo
- Publication number
- CN106640481A CN106640481A CN201611116021.5A CN201611116021A CN106640481A CN 106640481 A CN106640481 A CN 106640481A CN 201611116021 A CN201611116021 A CN 201611116021A CN 106640481 A CN106640481 A CN 106640481A
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- Prior art keywords
- draft tube
- spiral case
- eccentric vortex
- draft
- diameter
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03B—MACHINES OR ENGINES FOR LIQUIDS
- F03B11/00—Parts or details not provided for in, or of interest apart from, the preceding groups, e.g. wear-protection couplings, between turbine and generator
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03B—MACHINES OR ENGINES FOR LIQUIDS
- F03B11/00—Parts or details not provided for in, or of interest apart from, the preceding groups, e.g. wear-protection couplings, between turbine and generator
- F03B11/02—Casings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03B—MACHINES OR ENGINES FOR LIQUIDS
- F03B3/00—Machines or engines of reaction type; Parts or details peculiar thereto
- F03B3/12—Blades; Blade-carrying rotors
- F03B3/121—Blades, their form or construction
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Hydraulic Turbines (AREA)
Abstract
The invention relates to a method for reducing the harm of a draft tube eccentric vortex strip of a Francis hydraulic turbine. The method for reducing the harm of the draft tube eccentric vortex strip of the Francis hydraulic turbine comprises four aspects of optimization on the Francis hydraulic turbine. The four aspects of optimization are shown as follows: (1) the diameter of the tail end of a volute is increased, and the diameter of each cross section of the volute is increased from an inlet of the volute to the tail end of the volute in equal proportion; (2) the included angle between a water outlet edge of each blade and the horizontal plane is reduced; (3) a runner cone longer than a conventional runner cone is selected; and (4) a higher draft tube is selected.
Description
Technical field
The present invention relates to a kind of method for mitigating the harm of Draft Tube of Francis Turbine eccentric vortex band, belongs to hydraulic turbine technology
Field.
Background technology
Draft Tube of Francis Turbine eccentric vortex band is to cause that pressure fluctuation of hydraulic turbine is exceeded, power station is unable to stable operation
One of the main reasons, bring that unit vibration, throw are big and noise is big, factory vibration is big etc. to domestic and international many power stations and ask
Topic, even cause draft tube tear, runner blade crackle, factory building high vibration etc. having is destroyed, very harmful." draft tube is inclined
Heart vortex band pressure fluctuation " often occurs in 40%～80% guide vane opening area also known as " part load pressure pulsation ".Draft tube is eccentric
Vortex rope as shown in Figure 1 photos, in the shape of a spiral.The vortex rope formed by cavitation cavity in addition to rotation, also around deviating from draft tube geometry
" axis " revolution at center, therefore it is otherwise known as " spiral motion formula vortex rope " (see Fig. 2).The type vortex rope is most prominent to be characterized in that it
Vortex rope " bias " revolves round the sun, and what the size of its eccentric throw again can be approximate reflects the size of vortex band pressure fluctuation amplitude.
Draft tube bias vortex band pressure fluctuation belongs to low frequency pulsation, and its frequency is usually the 0.2 of rotational speed of water turbine frequency
～0.5 times.Because its frequency is low, amplitude of pressure fluctuation is big, and domestic Yan Tan power stations amplitude of pressure fluctuation is even as high as power station water
The 43.9% of head, destructive power is surprising, therefore receives much attention, and substantial amounts of research and exploration have all been carried out both at home and abroad, it was found that many
Phenomenon and rule, are also accumulated from substantial amounts of research data and solve the experience of vortex rope stability problem.
But, from the point of view of disclosed documents and materials, these researchs are deep not enough, are especially a lack of to eccentric vortex band
Generation and the essential understanding of hazard mechanism, the progress in terms of how mitigating eccentric vortex band harm is slow.Last century was once
Coaxial sleeve, current stabilization piece, airflow fence that Jing is explored in draft tube etc. limit vortex rope measure because it reduces efficiency, structure hardly possible surely
Gu the problems such as gradually abandoned, only tonifying Qi is still widely adopted at present, but because its can cause efficiency decline belong to helpless choosing
Select.Over nearly 20 years, although as the fast-developing of computer CFD technologies and progress, by the optimization design to the hydraulic turbine, in water
On the basis of turbine efficiency raising, cavitation performance improve, its hydraulic stability also accordingly improves, eccentric vortex band pressure arteries and veins
Dynamic amplitude decreases, but this belongs to process effects more, it is not clear that be which improvement plays a major role, which kind of effect brought,
Naturally also it is difficult in the same way.
Therefore, it is necessary to study the generation and hazard mechanism of draft tube bias vortex band pressure fluctuation, and have on this basis
Targetedly propose the effective measures and method for mitigating the pressure fluctuation.
The content of the invention
For the problems referred to above, it is an object of the invention to provide a kind of mitigate the harm of Draft Tube of Francis Turbine eccentric vortex band
Method, the method be on the basis of the producing cause for understanding fully draft tube eccentric vortex band propose, can effectively mitigate even
Eliminate the harm of draft tube eccentric vortex band.
For achieving the above object, the present invention is employed the following technical solutions：It is eccentric that one kind mitigates Draft Tube of Francis Turbine
Vortex rope harm method, including the following four to the hydraulic turbine in terms of optimization：1) increase spiral case end diameter, and enter from spiral case
Mouth increases each cross section diameter of spiral case to spiral case end equal proportion；2) angle between the outlet edge and horizontal plane of blade is reduced；
3) draft cone longer than conventional draft cone is selected；4) higher draft tube is selected.
Spiral case end diameter ratio after increase by etc. circular rector design spiral case end diameter it is big by 10%～15%.
Angle between the outlet edge and horizontal plane of blade is decreased to 8 °～22 ° by existing 10 °～25 °, and more leans on
Angle reduction amount is bigger at nearly crown.
Selected is 0.2～0.3 times that draft cone length reaches discharge diameter of runner.
Selected draft tube highly meets or exceeds 3 times of discharge diameter of runners.
Due to taking above technical scheme, it has advantages below to the present invention：1st, the present invention is to understand fully mixed-flow wheel
Tail water pipe eccentric vortex, with what is proposed on the basis of producing cause and hazard mechanism, is " suiting the remedy to the case ", can accomplish to shoot the arrow at the target,
It is with strong points.2nd, the measure for mitigating the harm of draft tube eccentric vortex band proposed by the present invention and method are all more specific, specify that and change
Where and how to change, operability is stronger.
Description of the drawings
Fig. 1 is Draft Tube of Francis Turbine eccentric vortex band photo；
Fig. 2 is eccentric vortex band revolution schematic diagram；
Fig. 3 is francis turbine runner import radial flow speed distribution map；
Fig. 4 is rotary wheel of water turbine rate of discharge maldistribution schematic diagram；
Fig. 5 is vortex band pressure fluctuation amplitude with cavitation coefficient, cavitation factor, Toma coefficient change curve；
Fig. 6 is francis turbine runner structural representation.
Specific embodiment
The present invention is described in detail with reference to the accompanying drawings and examples.
As shown in figure 1, the present invention proposes a kind of method of mitigation Draft Tube of Francis Turbine eccentric vortex band harm, its
Optimization in terms of including the following four to the hydraulic turbine：
1) optimize spiral case design, appropriate increase spiral case end diameter (than by etc. circular rector design spiral case end diameter
Increase 10%～15%), and from spiral case inlet to spiral case end equal proportion increase by etc. circular rector design spiral case each cross section diameter,
To increase spiral case end cross-sectional area, its conveyance capacity is increased, make each cross-sectional flow of spiral case evenly, and and then make to enter runner
Current evenly and symmetrically, to reduce the radial load that runner is brought because flow velocity is uneven, reduce draft tube vortex rope eccentric throw.
2) outlet edge 5 and horizontal plane angle of blade 2 are decreased to into 8 °～22 ° by 10 °～25 °, the leaf the closer at crown 1
The angle reduction of piece outlet edge 5 and horizontal plane is more, reduces the closer at lower ring 3 fewer, it might even be possible to do not subtract；Its objective is for
Reduce the ring flow velocity around draft cone 6, to reduce vortex rope cavity size, and and then reduce vortex rope eccentric throw, reduce eccentric
Vortex band pressure fluctuation amplitude.
3) draft cone longer than conventional draft cone (its length is about 0.1～0.15 times of discharge diameter of runner) is selected,
Draft cone length is set to reach 0.2～0.3 times of discharge diameter of runner, to consume more bias that residue in water is flowed out from runner
Power, makes current that the degree of crowding of the high side of flow velocity is reduced before leaving draft cone and stopping, reduction is left draft cone current direction and do not gathered around
The degree of crowded side skew, that is, reduce vortex rope eccentric throw；
4) higher draft tube is selected, such as makes draft tube highly meet or exceed 3 times of discharge diameter of runners, to increase vortex rope
With a distance from tail water bottom of the tube and side wall, mitigate impact of the vortex rope to standing part, reduce pressure fluctuation and shaking of being induced by it
Dynamic amplitude.
The method for mitigating the harm of Draft Tube of Francis Turbine eccentric vortex band proposed by the invention, is based on " cavity is endangered
Evil hydraulic Theory of Stability ", is proposed on the basis of the generation and hazard mechanism of analysis draft tube eccentric vortex band.Root
Further investigation according to " cavity endangers hydraulic Theory of Stability " and to draft tube eccentric vortex band, finds following phenomenon and rule
Rule：
(1) draft tube vortex rope, no matter it is straight whirlpool, or helical form eccentric vortex band, result from annular liquid flow at the runner exit, shadow
Ring vortex rope center (center of vorticity) flow velocity maximum is the outlet circulation of runner inner side (at runner crown 1)；
(2) vortex rope eccentric throw is parameter more prior than cavity vortex rope diameter；In general, eccentric throw is bigger, draft tube
Vortex band pressure fluctuation amplitude is bigger, but the big amplitude of pressure fluctuation of vortex rope cavity diameter is not necessarily big；
(3) spiral case of the hydraulic turbine and asymmetric design, the stream of the entrance runner that the water part such as itself and fixed guide vane is formed
Fast field and pressure field also asymmetric (as shown in Figure 3)；The circumferential uneven biography of the asymmetric flow velocity for causing of water part
Pass runner, formed after runner mass flow discrepancy shown in Fig. 4 it is even and it is runner both sides it is asymmetric (side flow is big, current compared with
It is crowded；Opposite side flow is little, and current are sparse), when the constraint of runner cone is left, current will certainly be caused big by flow
A lateral flow it is little side skew, therefore and produce vortex rope deviate pivot；Flow velocity degree of irregularity is higher, the bias
Away from bigger；Routinely etc. the spiral case of circular rector design generally all has that spiral case end flow velocity is low, is to cause stream shown in Fig. 3
The uneven main cause of speed；
(4) as cavitation coefficient, cavitation factor, Toma coefficient σ reduces (both tail water draught-height HsIncrease), vortex rope cavity diameter increase, vortex rope is eccentric
Away from also increasing, vortex band pressure fluctuation may significantly rise as shown in Figure 5；But, as σ is further reduced, pressure fluctuation
Amplitude can turn around to decline again.
The present invention is only illustrated with above-described embodiment, and the structure of each part, set location and its connection all can be have
Changed.On the basis of technical solution of the present invention, all individual part is carried out improvement according to the principle of the invention or equivalent
Conversion, should not exclude outside protection scope of the present invention.
Claims (5)
1. it is a kind of to mitigate the method that Draft Tube of Francis Turbine eccentric vortex band endangers, including the following four aspect to the hydraulic turbine
Optimization：1) increase spiral case end diameter, and each cross section diameter of spiral case is increased from spiral case inlet to spiral case end equal proportion；2)
Reduce the angle between the outlet edge and horizontal plane of blade；3) draft cone longer than conventional draft cone is selected；4) from higher
Draft tube.
2. the method that a kind of mitigation Draft Tube of Francis Turbine eccentric vortex band as claimed in claim 1 endangers, its feature exists
In：Spiral case end diameter ratio after increase by etc. circular rector design spiral case end diameter it is big by 10%～15%.
3. the method that a kind of mitigation Draft Tube of Francis Turbine eccentric vortex band as claimed in claim 1 endangers, its feature exists
In：Angle between the outlet edge and horizontal plane of blade is decreased to 8 °～22 ° by existing 10 °～25 °, and the closer to crown
Place's angle reduction amount is bigger.
4. the method that a kind of mitigation Draft Tube of Francis Turbine eccentric vortex band as claimed in claim 1 endangers, its feature exists
In：Selected is 0.2～0.3 times that draft cone length reaches discharge diameter of runner.
5. the method that a kind of mitigation Draft Tube of Francis Turbine eccentric vortex band as claimed in claim 1 endangers, its feature exists
In：Selected draft tube highly meets or exceeds 3 times of discharge diameter of runners.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611116021.5A CN106640481B (en) | 2016-12-07 | 2016-12-07 | A method of mitigating the harm of Draft Tube of Francis Turbine eccentric vortex band |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611116021.5A CN106640481B (en) | 2016-12-07 | 2016-12-07 | A method of mitigating the harm of Draft Tube of Francis Turbine eccentric vortex band |
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| CN106640481A true CN106640481A (en) | 2017-05-10 |
| CN106640481B CN106640481B (en) | 2019-07-19 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110410259A (en) * | 2019-08-07 | 2019-11-05 | 东方电气集团东方电机有限公司 | A kind of leaf head cantilever type runner |
| CN111255624A (en) * | 2020-03-05 | 2020-06-09 | 华电宁德电力开发有限公司 | Method for reducing damage of heavy-load drum-shaped vortex band of mixed-flow water turbine |
Citations (5)
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|---|---|---|---|---|
| CN2081436U (en) * | 1990-12-01 | 1991-07-24 | 黄国宏 | Mixed flow hydraulic turbine drainage awl stretching taper sleeve (conical pipe) |
| CN201083177Y (en) * | 2007-10-12 | 2008-07-09 | 杭州电子科技大学 | Draft tube |
| US20090087305A1 (en) * | 2007-09-28 | 2009-04-02 | Alexander Gokhman | Exit stay apparatus with intermediate flange |
| CN102011672A (en) * | 2010-12-08 | 2011-04-13 | 清华大学 | Radial-axial flow turbine employing novel guide blade and runner blade profile |
| JP2011117465A (en) * | 2011-03-25 | 2011-06-16 | Toshiba Corp | Bent draft pipe for hydraulic machine |
-
2016
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2081436U (en) * | 1990-12-01 | 1991-07-24 | 黄国宏 | Mixed flow hydraulic turbine drainage awl stretching taper sleeve (conical pipe) |
| US20090087305A1 (en) * | 2007-09-28 | 2009-04-02 | Alexander Gokhman | Exit stay apparatus with intermediate flange |
| CN201083177Y (en) * | 2007-10-12 | 2008-07-09 | 杭州电子科技大学 | Draft tube |
| CN102011672A (en) * | 2010-12-08 | 2011-04-13 | 清华大学 | Radial-axial flow turbine employing novel guide blade and runner blade profile |
| JP2011117465A (en) * | 2011-03-25 | 2011-06-16 | Toshiba Corp | Bent draft pipe for hydraulic machine |
Non-Patent Citations (3)
| Title |
|---|
| 中国水力发电工程学会水力机械专业委员会等: "《水电设备的研究与实践-第20次中国水电设备学术讨论会论文集》", 31 October 2015, 中国水利水电出版社 * |
| 李启章等: "《混流式水轮机水力稳定性研究》", 31 August 2014, 中国水利水电出版社 * |
| 李延频: "《余能回收用工业水轮机的研究》", 31 March 2016, 中国水利水电出版社 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110410259A (en) * | 2019-08-07 | 2019-11-05 | 东方电气集团东方电机有限公司 | A kind of leaf head cantilever type runner |
| CN111255624A (en) * | 2020-03-05 | 2020-06-09 | 华电宁德电力开发有限公司 | Method for reducing damage of heavy-load drum-shaped vortex band of mixed-flow water turbine |
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| Publication number | Publication date |
|---|---|
| CN106640481B (en) | 2019-07-19 |
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