CN204185836U - Variable-section surge chamber - Google Patents

Abstract

The utility model discloses a kind of variable-section surge chamber, its barrel comprises the first surge-chamber section, cross-sectional area transition section and the second surge-chamber section successively along short transverse, cross-sectional area transition section connects the first surge-chamber section and the second surge-chamber section, wherein, first surge-chamber section cross-sectional area is surge-chamber stable cross section area corresponding to downstream low water stage, the surge-chamber stable cross section area that second surge-chamber section cross-sectional area is corresponding when being flowing full, in particular cases can not establish cross-sectional area transition section.The utility model is applicable to free pressure flow tail water discharge, can reduce the scale of downstream surge-chamber, is conducive to the stable of underground hole group, reduces cavern excavation and support engineering amount, reduce construction costs.

Description

Variable-section surge chamber

Technical field

The utility model relates to hydraulic power plant surge-chamber structure pattern, particularly relates to a kind of variable-section surge chamber being applicable to free pressure flow tail water discharge.

Background technology

Along with the exploitation of Southwestern China waterpower resourses, residing for many huge, large hydropower stations planned, design and construct, section landform is steep, river valley is narrow, riverbed only can be used for arranging dash and flood releasing structure, and water delivery power generation construction thing, water conservancy diversion and part flood releasing structure must be arranged in the massif of two sides, this is comparatively typical a kind of hinge general arrangement general layout.

When power station adopts stem formula and middle part formula development scheme, tailwater tunnel is longer, generally need arrange downstream surge-chamber (3) and meet the requirement that draft tube of hydropower station admission section (4) minimum absolute pressure meets specification and design.In order to reduce the engineering quantity of tailwater tunnel and tailrace outlet side slope in engineering reality, avoid excavation supporting and the stable problem of artificial high gradient slope, alleviate the destroying infection to surface vegetation and environment, often need to consider " forever facing combination ", namely the temporary building making full use of the construction period combines with permanent building, carry out unified layout and design, power plant tail water hole is combined with Diversion Tunnel, just may become a kind of and compare the arrangement had superiority.

Flat slope pattern should be selected with Diversion Tunnel in conjunction with hole section (9) in power plant tail water hole as far as possible, take into account and adapt to power plant tail water hole and Diversion Tunnel go out to flow requirement, in the water-carriage system with this downstream surge-chamber and free pressure flow tailrace tunnel, when downstream, tailwater level changes to high water level from low water stage, the streamflow regime of free flow, free pressure flow and flowing full is presented, whole tailrace tunnel length when tail water has the length of pressure section correspondingly to reach flowing full by minimum length during minimum tailwater level in tailrace tunnel.According to streamflow regime and the waterpower feature of tailrace tunnel, downstream surge-chamber (3) barrel section can break through conventional equal section pattern, adopt the Varied section pattern of different area and shape, to reducing downstream surge-chamber scale, be conducive to the stable of underground hole group, reduce cavern excavation and support engineering amount, reduce construction costs.

According to " hydraulic power plant surge-chamber design specifications ", the stable cross section area F of downstream surge-chamber is:

F＝KF _Th(1)

$F_{\mathrm{Th}}=\frac{\mathrm{Lf}}{2\mathrm{g\α}(H_0-h_{w0}-{3h}_{\mathrm{wm}})}---\left(2\right)$

In formula (1) ~ (2):

F _thfor holder horse neutrality cross-sectional area, unit: m ²;

L is pressure tail water road length, unit: m; Described pressure tail water road is that downstream surge-chamber is to the pressure conduit between free pressure flow interface or tailrace outlet;

F is pressure tail water road cross-sectional area, unit: m ²;

H ₀for the minimum gross head that generates electricity, unit: m;

α is downstream surge-chamber to the loss coefficient of downstream river course or reservoir head, comprises local head loss and frictional head loss, α=h _w0/ v ²;

V is pressure tail water road mean flow rate, unit: m/s;

H _w0for the road head loss of pressure tail water, unit: m;

H _wmfor the loss of downstream surge-chamber upstream line gross head, comprise pressure pipeline and the head loss of draft tube extension, unit: m;

K is coefficient, generally chooses in 1.0 ~ 1.1, selects during K < 1.0 and should have reliable demonstration;

G is acceleration of gravity, unit: m/s ².

Utility model content

The purpose of this utility model is to provide a kind of variable-section surge chamber being applicable to free pressure flow tail water discharge, free pressure flow tail water discharge middle and lower reaches surge-chamber scale can be reduced, be conducive to the stable of underground hole group, reduce cavern excavation and support engineering amount, reduce construction costs.

For achieving the above object, the technical solution of the utility model is as follows:

A kind of variable-section surge chamber, its barrel comprises the first surge-chamber section, cross-sectional area transition section and the second surge-chamber section from bottom to up successively along short transverse, cross-sectional area transition section connects the first surge-chamber section and the second surge-chamber section, wherein, first surge-chamber section cross-sectional area is surge-chamber stable cross section area corresponding to downstream low water stage, surge-chamber stable cross section area corresponding when the second surge-chamber section cross-sectional area is flowing full; First surge-chamber section is identical with the section configuration of the second surge-chamber section or not identical, and section configuration designs according to the actual requirements; Set according to the downstream low water stage of Practical Project and tailrace outlet runner crest level with crest level bottom cross-sectional area transition section, and under guaranteeing various operating mode, Water Hammer parameter meets the requirement of specification and design.

The section configuration of above-mentioned first surge-chamber section, cross-sectional area transition section and the second surge-chamber section is rectangle, circle, ellipse or half elliptic.

Another kind of variable-section surge chamber, its barrel comprises the first surge-chamber section and the second surge-chamber section from bottom to up successively along short transverse, first surge-chamber section cross-sectional area is adopt the flow channel length of tiltedly section outlet in surge-chamber to free pressure flow tailrace tunnel to be the surge-chamber stable cross section area of pressure tail water road length computation, surge-chamber stable cross section area corresponding when the second surge-chamber section cross-sectional area is flowing full; First surge-chamber section is identical with the section configuration of the second surge-chamber section or not identical, and section configuration designs according to the actual requirements; The free pressure flow tailrace tunnel middle connecting segment input elevation that first surge-chamber section crest level connects adit pattern according to the oblique hole of Practical Project sets, and under guaranteeing various operating mode, Water Hammer parameter meets the requirement of specification and design.

When the free pressure flow tailrace tunnel that oblique hole connects adit pattern does not comprise linkage section, the first surge-chamber section crest level is according to the setting of Practical Project tailrace outlet runner crest level, and under guaranteeing various operating mode, Water Hammer parameter meets the requirement of specification and design.

The section configuration of above-mentioned first surge-chamber section and the second surge-chamber section is rectangle, circle, ellipse or half elliptic.

Free pressure flow tail water discharge refers to a kind of hydropower station tail water water-carriage system be made up of buildings such as the draft tube be connected successively, downstream surge-chamber, free pressure flow tailrace tunnel and tailrace outlets.When power station adopts free pressure flow tail water discharge, especially when free pressure flow tailrace tunnel part hole section is adit, conventional equal section pattern surge-chamber can be broken through, adopt the surge-chamber of Varied section pattern, namely surge-chamber adopts different cross-sectional areas and section configuration along short transverse, to reducing the scale of downstream surge-chamber, is conducive to the stable of underground hole group, reduce cavern excavation and support engineering amount, reduce construction costs.

Accompanying drawing explanation

Fig. 1 is the free pressure flow tail water discharge vertical section schematic diagram of oblique hole pattern;

Fig. 2 is the free pressure flow tail water discharge vertical section schematic diagram that oblique hole connects adit pattern;

Fig. 3 is the surge-chamber structure schematic diagram of downstream section gradient, wherein, figure (a) flows to sectional drawing downstream for surge-chamber, figure (b) is surge-chamber A-A sectional drawing in figure (a), figure (c) is surge-chamber B-B sectional drawing in figure (a), and figure (d) is surge-chamber C-C sectional drawing in figure (a);

Fig. 4 is the surge-chamber structure schematic diagram of both sides section gradient, wherein, figure (a) flows to sectional drawing downstream for surge-chamber, figure (b) is surge-chamber D-D sectional drawing in figure (a), figure (c) is surge-chamber E-E sectional drawing in figure (a), and figure (d) is surge-chamber F-F sectional drawing in figure (a);

Fig. 5 is the surge-chamber structure schematic diagram of the downstream abrupt change of cross section, wherein, figure (a) flows to sectional drawing downstream for surge-chamber, figure (b) is surge-chamber G-G sectional drawing in figure (a), figure (c) is surge-chamber H-H sectional drawing in figure (a), and figure (d) is surge-chamber I-I sectional drawing in figure (a);

Fig. 6 is the surge-chamber structure schematic diagram of the both sides abrupt change of cross section, wherein, figure (a) flows to sectional drawing downstream for surge-chamber, figure (b) is surge-chamber J-J sectional drawing in figure (a), figure (c) is surge-chamber K-K sectional drawing in figure (a), and figure (d) is surge-chamber L-L sectional drawing in figure (a).

Wherein, 1-underground power house, 2-main transformer hole, 3-downstream surge-chamber, 4-draft tube admission section, 5-draft tube, 6-bifurcated pipe section, the oblique section of 7-free pressure flow tailrace tunnel, 8-linkage section, the 9-free pressure flow tailrace tunnel section of putting down, 10-tailrace outlet, 11-downstream low water stage, 12-downstream middle water level, 13-downstream high water level, 14-free pressure flow interface, 15-pressure tail water road segment length L1,16-free flow segment length L2 with no pressure, 17-free pressure flow tailrace tunnel length L, 18-first surge-chamber section, 19-second surge-chamber section.

Detailed description of the invention

Technical solutions of the utility model are further illustrated below in conjunction with accompanying drawing.

Fig. 1 is the free pressure flow tail water discharge vertical section schematic diagram of oblique hole pattern, free pressure flow tail water discharge comprises the draft tube (5), downstream surge-chamber (3), free pressure flow tailrace tunnel (7) and the tailrace outlet (10) that are connected successively, the free pressure flow tailrace tunnel in downstream surge-chamber (3) downstream is oblique hole, i.e. the oblique section of free pressure flow tailrace tunnel (7).When tailwater level from downstream low water stage (11) rise to close to tailrace outlet (10) hole crest level downstream middle water level (12), again to the process of downstream high water level (13), pressure tail water road segment length L1 (15) rises to free pressure flow tailrace tunnel total length L gradually.From formula (1) and formula (2), the stable cross section area of downstream surge-chamber increases to F2 by F1 and is increased to F again, F1 is the downstream surge-chamber stable cross section area of downstream low water stage (11) correspondence, F2 is the downstream surge-chamber stable cross section area of downstream middle water level (12) correspondence, downstream surge-chamber stable cross section area corresponding when F is flowing full.When calculating downstream surge-chamber stable cross section area, in formula (1) ~ (2), each variable is all according to actual conditions value or calculating.

For the oblique hole pattern free pressure flow tail water discharge shown in Fig. 1, in the calculating of downstream low water stage and surge-chamber stable cross section area F1 and F2 corresponding to downstream middle water level, pressure tail water road length is downstream surge-chamber (3) to the free pressure flow tailrace tunnel length between free pressure flow interface (14) corresponding to corresponding tailwater level; In the calculating of surge-chamber stable cross section area F corresponding during flowing full, pressure tail water road length is free pressure flow tailrace tunnel overall length L, the free pressure flow tailrace tunnel length namely between downstream surge-chamber (3) to tailrace outlet (10).

Fig. 2 is the free pressure flow tail water discharge vertical section schematic diagram that oblique hole connects adit pattern, free pressure flow tail water discharge comprises the draft tube (5) be connected successively, downstream surge-chamber (3), free pressure flow tailrace tunnel and tailrace outlet, free pressure flow tailrace tunnel comprises the oblique section of free pressure flow tailrace tunnel (7), linkage section (8) and the free pressure flow tailrace tunnel section of putting down (9), the oblique section of free pressure flow tailrace tunnel (7) outlet is connected by linkage section (8) with the free pressure flow tailrace tunnel section of putting down (9) import, downstream surge-chamber (3) connects free pressure flow tailrace tunnel oblique section (7) entrance, the free pressure flow tailrace tunnel section of putting down (9) outlet connects tailrace outlet and tailwater channel.When tailwater level from downstream low water stage (11) rise to close to tailrace outlet (10) hole crest level downstream middle water level (12), again to the process of downstream high water level (13), pressure tail water road length rises to free pressure flow tailrace tunnel total length L gradually by L1 (15).Surge-chamber stable cross section area F corresponding when the surge-chamber stable cross section area F2 that the surge-chamber stable cross section area F1 adopting calculating downstream, formula (1) ~ (2) low water stage corresponding, downstream middle water level are corresponding and flowing full.Consider that the oblique section of free pressure flow tailrace tunnel (7) length is relatively short, and the free pressure flow tailrace tunnel section of putting down (9) length is longer, downstream surge-chamber cross-sectional area has a sudden change when the free pressure flow tailrace tunnel section of putting down (9) hole crest level, in order to simplified design and reduction difficulty of construction, be that downstream surge-chamber is divided into two sections by boundary with linkage section (8) input elevation: the first surge-chamber section and the second surge-chamber section.When not establishing linkage section, the first surge-chamber section crest level can be chosen for a little less than the free pressure flow tailrace tunnel section of putting down (9) hole crest level.Using downstream surge-chamber stable cross section area F2 corresponding to the middle water level of linkage section (8) input elevation as the first surge-chamber section cross-sectional area, when calculating downstream surge-chamber stable cross section area F2, be pressure tail water road length with the free pressure flow tailrace tunnel length of linkage section (8) import upstream side, in formula (1) ~ (2), other variable is according to actual conditions value or calculating.

Detailed description of the invention of the present utility model is as follows:

According to the actual arrangement situation of power station water-carriage system, surge-chamber stable cross section area corresponding when adopting formula (1) and (2) to calculate downstream low water stage, downstream middle water level, flowing full respectively.For the free pressure flow tail water discharge layout pattern shown in Fig. 1 and Fig. 2, surge-chamber cross-sectional area can be adopted respectively along short transverse gradual change (see Fig. 3 and Fig. 4) and surge-chamber cross-sectional area along two kinds of surge-chamber patterns of short transverse sudden change (see Fig. 5 and Fig. 6).

See Fig. 3 ~ 4, the first surge-chamber pattern, its barrel comprises the first surge-chamber section, cross-sectional area transition section and the second surge-chamber section successively along short transverse, and cross-sectional area transition section connects the first surge-chamber section and the second surge-chamber section.This surge-chamber pattern is applicable to the free pressure flow tail water discharge shown in Fig. 1, and the first surge-chamber section cross-sectional area is surge-chamber stable cross section area corresponding to downstream low water stage, surge-chamber stable cross section area corresponding when the second surge-chamber section cross-sectional area is flowing full.Cross-sectional area transition section Bottom Altitude can be chosen a little less than downstream low water stage, and its crest level can be chosen a little less than tailrace outlet crest level.The section configuration of the first surge-chamber section, cross-sectional area transition section and the second surge-chamber section is selected according to actual requirement of engineering, and section configuration is selected convenient construction as far as possible, can be improved and reduce the shape that Stability of Excavation Surrounding was concentrated, was conducive to surrouding rock stress.Fig. 3 and Fig. 4 sets forth the surge-chamber structure of downstream gradual change and both sides gradual change.

See Fig. 5 ~ 6, the second surge-chamber pattern, its barrel comprises the first surge-chamber section and the second surge-chamber section successively along short transverse, and this surge-chamber pattern is applicable to the free pressure flow tail water discharge shown in Fig. 2.In the calculating of the first surge-chamber section cross-sectional area, the free pressure flow tailrace tunnel length exported with surge-chamber to the oblique section of free pressure flow tailrace tunnel (7) is surge-chamber stable cross section area corresponding to pressure tail water road length computation, and is the first surge-chamber cross-sectional area with this surge-chamber stable cross section area.The surge-chamber stable cross section area F that second surge-chamber section cross-sectional area is corresponding when being flowing full, pressure tail water road length is the free pressure flow tailrace tunnel length between downstream surge-chamber (3) to tailrace outlet (10).First surge-chamber section crest level initial value sets with linkage section (8) input elevation or tailrace outlet runner crest level, then the needs calculated according to Practical Project Calculations of Hydraulic Transient adjust, and guarantee that Water Hammer parameter meets the requirement of specification and design under various operating mode.

The variable-section surge chamber's structure in Fig. 3 ~ 6 can be chosen when adopting gallery type surge-chamber; When adopting cylinder type or semi cylindrical type surge-chamber, visual actual conditions are by changing cross sectional radii or the section configuration (as shapes such as oval or semiellipses) of surge-chamber barrel first surge-chamber section, carry out the area requirements of satisfied first surge-chamber section, and connected with the second surge-chamber section by transition section and sudden change.When being applied to multimachine one hole one Room tail water discharge, bifurcated pipe section (6) visual concrete condition is arranged in bottom surge-chamber downstream (see Fig. 3 and Fig. 5) or surge-chamber (see Fig. 4 and Fig. 6).

The utility model is not only applicable to the Hydraulic unit of Room, multimachine one hole one, is also applicable to the Hydraulic unit of a Room, machine one hole one.

In two kinds of free pressure flow tail water discharge layout patterns that the utility model provides, downstream surge-chamber stable cross section area computation method has Surge Chamber in pressure tailrace tunnel layout pattern identical with conventional, keeps correct corresponding relation when should be noted other parameter value in calculating.

Claims (5)

1. variable-section surge chamber, is characterized in that:

Variable-section surge chamber's barrel comprises the first surge-chamber section, cross-sectional area transition section and the second surge-chamber section from bottom to up successively along short transverse, cross-sectional area transition section connects the first surge-chamber section and the second surge-chamber section, wherein, first surge-chamber section cross-sectional area is surge-chamber stable cross section area corresponding to downstream low water stage, surge-chamber stable cross section area corresponding when the second surge-chamber section cross-sectional area is flowing full; First surge-chamber section is identical with the section configuration of the second surge-chamber section or not identical; Set according to the downstream low water stage of Practical Project and tailrace outlet runner crest level with crest level bottom cross-sectional area transition section.

2. variable-section surge chamber as claimed in claim 1, is characterized in that:

The section configuration of the first described surge-chamber section, cross-sectional area transition section and the second surge-chamber section is rectangle, circle, ellipse or half elliptic.

3. variable-section surge chamber, is characterized in that:

Variable-section surge chamber's barrel comprises the first surge-chamber section and the second surge-chamber section from bottom to up successively along short transverse, first surge-chamber section cross-sectional area is adopt the flow channel length of tiltedly section outlet in surge-chamber to free pressure flow tailrace tunnel to be the surge-chamber stable cross section area of pressure tail water road length computation, surge-chamber stable cross section area corresponding when the second surge-chamber section cross-sectional area is flowing full; First surge-chamber section is identical with the section configuration of the second surge-chamber section or not identical; The free pressure flow tailrace tunnel middle connecting segment input elevation that first surge-chamber section crest level connects adit pattern according to the oblique hole of Practical Project sets.

4. variable-section surge chamber as claimed in claim 3, is characterized in that:

When the free pressure flow tailrace tunnel that oblique hole connects adit pattern does not comprise linkage section, the first surge-chamber section crest level is according to the setting of Practical Project tailrace outlet runner crest level, and under guaranteeing various operating mode, Water Hammer parameter meets the requirement of specification and design.

5. variable-section surge chamber as claimed in claim 3, is characterized in that:

The first described surge-chamber section and the section configuration of the second surge-chamber section are rectangle, circle, ellipse or half elliptic.