JPH057305Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Field of Application> This invention relates to a deflector for reducing the energy of a jet of water discharged from a high-pressure slide gate or the like.

<Conventional technology> In general, a jet flow (here, a method that generates a cavity phenomenon)
(7m/sec or more) The high-speed flow released from the outlet has a large amount of energy (velocity x mass).

Conventionally, in dams, etc., in order to reduce the energy, a reduction pond was installed downstream of the outlet.
Either direct the jet flow directly into the deenergization pond, or
In both cases, a method was used in which a jet stream was discharged into the air and allowed to fall into a deenergizing pond, causing a water jump. In both cases, the de-energized water was de-energized in the pond and turned into a regular flow, flowing downstream.

In addition, when discharging water into a tunnel, the height of the outlet should be set low to reduce the amount of excavation, and a jump-type energy reducer should be installed to reduce energy by vortices, velocity shearing force, etc. A method was used in which a regular flow with a flow rate of 2 to 3 m/sec was made to flow downstream in the direction of the tunnel waterway.

FIG. 15 shows an example of the above-mentioned jump-type energy reducer, in which high-pressure water from the high-pressure iron pipe 1 passes through the high-pressure slide gate 4 and is discharged into the energy-reducing pond 5 from the outlet 2 as a jet stream. Ru. The deenergization pond 5 is larger than the cross section of the tunnel waterway 7, and its length is the same as that of the outlet 2.
The distance L _s1 to the landing point of the jet and the length of the jump
L _b (equivalent to the distance from the landing point to downstream weir 6)
It becomes the depleted pond length L by adding . The cross section of this energy reduction pond 5 is usually larger than the cross section of the tunnel waterway 7.
Therefore, it has problems of difficulty in construction and increase in construction cost, so it is preferable that the deenergization pond length L be short. For example, if the height _W1 of the discharge port 2 is set to 1 to 2 m for maintenance purposes of the high-pressure slide gate 4, the distance L _s1 will be 10 to 20 m when the jet flow velocity is 20 m/sec, and the deenergization pond length L will be 10 to 20 m. The length of the pond L is approximately 38m.
Of this deenergization pond length L, the jump length L _b is a length that is unavoidable due to hydraulic phenomena, and in order to shorten the distance L _s1 to the landing point of the jet flow, conventionally the jump length L b is As shown, a flat deflector plate 41 is provided at an angle of depression immediately downstream of the discharge port 2 to deflect the jet flow downward.

<Problem to be solved by the invention> However, although the deflector with such a conventional structure effectively achieves a direction changing effect when the jet flow is a small flow rate of 1 to 2 m ³ /sec, it cannot When the jet collides with the deflector plate, vibrations occur in the deflector plate, and reflected waves of the jet flow occur, and the water pressure collides with the following water flow, causing turbulence. cause problems.

The vibration of the deflector plate in the former case may be transmitted through the bedrock and damage the structure, so
Flat deflectors are not used in rockfields. The latter occurrence of turbulent flow due to reflected waves causes pressure fluctuations in the diverted effluent water, resulting in a problem in that the flow is not rectified, resulting in a reduction in the energy-reducing effect.

This invention was made to solve the above problem, and its purpose is to prevent the generation of vibrations and reflected waves due to collision of jets, change the direction of jets, and reduce jets with a large energy-reducing effect. The purpose of this project is to provide a deflector for energy use.

<Means for solving the problem> This invention was made in order to achieve the above object, and is provided directly downstream of the outlet to face the jet stream discharged from the outlet, so that the direction of the jet stream can be adjusted. The deflector is a deflector for jet energy reduction, which is equipped with a deflection surface that deflects the jet flow, and the deflection surface has a vertical cross-sectional shape in the flow direction of the jet flow, and has a curved shape that moves downward with increasing acceleration toward the downstream side. This is a deflector for reducing the radiation energy.

<Operation> This device is constructed as described above, and the upper part of the jet water flux discharged from the outlet first enters the gentle curvature part of the deflection surface of the deflector plate, and then It flows down along the surface, and as it goes downstream, it changes its direction downward at an accelerated rate, and at the same time, it changes its direction in the horizontal direction where the slope is gentle.

As the direction of the upper layer changes, the middle layer of the jet water flux becomes obliquely downward toward the downstream side, and furthermore, the lower layer portion becomes more downward toward the downstream side as the middle layer changes direction.

In this way, the jet water flux is smoothly diffused laterally and weakened as it goes downstream due to the downwardly accelerating curved surface, and flows out at a downward angle, uniformly spreading over the width of the channel. It is effectively diffused to shorten the distance to the landing point.

<Example> Hereinafter, an example of this invention will be described based on the drawings.

Fig. 1 shows a vertical sectional view of a deflector for jet energy reduction according to an embodiment of this invention, and Fig. 2 shows a plan view.
FIG. 3 is an explanatory diagram of a longitudinal section of the direction change surface. In the following description, the same components as those of the conventional example are given the same reference numerals and the description thereof will be omitted.

Reference numeral 10 denotes a deflector for jet energy reduction (hereinafter abbreviated as deflector 10), which is a deflector plate having a deflection surface 13 formed in a curved shape whose vertical cross-section moves downward at an accelerating rate toward the downstream side. 11
, a stiffener 14 for reinforcing and fixing the deflector plate 11, a concrete wall 15 as a structure, and an air chamber 1 for supplying air to the jet flow.
8, an air supply pipe 19, etc.

The deflector plate 11 is made of a stainless steel plate in the embodiment, and the vertical cross-sectional shape of the deflection surface 13 in contact with the jet flow is basically 1/4 circle of an imaginary ellipse E, which is a quadratic curve, as shown in FIG. It is formed as.
That is, the virtual ellipse E is formed, for example, into a standard ellipse of (X/a) ² + (Y/b) ² = 1, and as a result of a hydraulic experiment, a is approximately twice the pipe diameter D of the high-pressure iron pipe 1. It is desirable that b be approximately the same as the pipe diameter D. Then, the long axis F is aligned with the lower inner diameter line of the high-voltage iron pipe 1, the short axis G is set at a position separated by the length A of the air chamber 18 from the end of the high-pressure iron pipe 1, and the apex of the short axis G is 1
Match the height of the upper inner diameter line.

The deflection surface 13 is formed in a curved shape having an initial curve extension H at the apex of the short axis G and a final curve point located 1/4 circle above the virtual ellipse E. As shown in FIG. 2, its planar shape is formed into a trapezoidal shape that widens toward the downstream side.

The end points K ₁ , K ₂ , and K ₃ shown in FIG. 3 indicate typical end points. For example, the end point K ₁ is
It is located at the intersection of the extension line M of the center line of the pipe diameter D and the 1/4 circle of the virtual ellipse E. In this case, 1/ of the jet flow
2 is directly deflected by the deflection surface 13, the jet flows downward at an angle of approximately 30°, and the center of the landing point is at the second
This is the _P1 position in the figure.

The end point K ₂ is located at the intersection of the horizontal line N and 1/4 circle above the major axis F by 1/4 of the pipe diameter D.
In this case, 3/4 of the jet flow is directly deflected by the deflection surface 13, and the jet flow flows downward at an angle of approximately 40°.
The center of the implantation point will be _P2 .

Further, the terminal point K ₃ is located at the apex of the long axis F, and in this case, the jet flows downward at an angle of about 45°, and the center of the landing point is P ₃ .

The selection of these end points K ₁ , K ₂ , K ₃ is done taking into account the flow rate, flow velocity, etc. The flow rate is 10 m ³ /
If it is more than sec, adopt the terminal point K ₁ ~ K ₂ and 10
If it is less than m ³ /sec, the end points K ₂ to _{K 3} are adopted. In addition, if the flow velocity is 15 m/sec or more, the end point
K ₁ to K ₂ are adopted, and if the speed is 15 m/sec or less, the end point is used.
_K1 to _K2 are adopted. In addition, in the case of underwater discharge (the discharge port 2 is underwater), the end point _K1 is selected.

The direction changing surface 13 of the example has a pipe diameter D = 600 mm,
The vertical section is a hypothetical ellipse E in which 1/2 of the major axis F is 1.75 times the pipe diameter D, i.e. 1050 mm, and 1/2 of the short axis G is 600 mm, which is the same as the pipe diameter D, and the end point is average. An end point K ₂ is set that has a significant direction change and force reduction effect. The starting point H of the direction change surface 13 is formed with a predetermined curvature so as to smoothly contact the outer periphery of the jet water flux, and the ending point K ₂ is formed approximately at a right angle.

The deflector plate 11 having the deflection surface 13 configured in this way has an air chamber 18 between it and the high-pressure iron pipe 1, and also has a stiffener 1.
4 to the concrete wall 15.

The air chamber 18 has a predetermined length A in the upper half of the opening of the outlet 2 and opens downward, and is communicated with the atmosphere in the energy reduction pond 5 via an air supply pipe 19. And, it is formed so as to supply a predetermined amount of air to the jet flow from the outlet 2.

The deflector 10 for jet energy reduction configured in this manner is installed, for example, as shown in FIG. 4, immediately downstream of the discharge port 2 of the high-pressure iron pipe 1 having the high-pressure slide gate 4 at its end.

In the jet stream discharged from the discharge port 2, a relatively upper part of the water flux enters the gentle curvature part of the quadratic curved surface starting from the starting point H of the deflection surface 13 of the deflector plate 11, and is deformed. It flows down along the facing surface 13, and the further downstream it goes, the more rapidly it changes direction downward and laterally.

In addition, the middle layer of the water bundle tends to become more downward and sideways toward the downstream as the upper layer of the water bundle changes direction, and the lower layer of the water bundle tends to become more downward and more downstream as the middle layer changes.

Therefore, the jet stream changes direction smoothly along the direction change surface 13 without generating reflected waves, and reaches the final turning point.
In part _K2 , the water flux becomes a flat ellipse as shown in Figure 5, and the jet strength is greatly reduced in the state of lateral diffusion, and the water flux is directed downward at an angle of approximately 40° to the deenergization pond 5.
leaks to. The energy of the jet flow at this terminal point K ₂ becomes a fraction of the energy of the outlet 2 due to the lateral diffusion effect, and at the landing point P ₂ the jet flow spreads to almost the entire width of the deenergization pond 5, The next state of deenergization is entered (see Figure 6).

This deflector 10 has a flow rate of
6.5m ³ /sec, when the flow velocity is 25m/sec, the change in direction,
Due to the force reduction effect, the distance L _s2 was 6 m, which was confirmed to be significantly shorter than the distance L _s1 of 21 m in the conventional example.

FIGS. 7 to 10 show other embodiments of this invention, which are characterized by the configuration of the deflection surface.

In the deflector plate 21 of the second embodiment, a water dividing plate 22 extending in the front-rear direction is provided in a hanging shape in the center, and the water dividing plate 22 moves downward at an accelerating rate toward the downstream side, and separates from the side end portions. Cubic curved direction changing surfaces 23, 2 that move downward at an accelerating rate toward the water plate 22
3 is formed.

The lowest point of this direction changing surface 23 is formed at the same height as the water dividing plate 22, and a predetermined position above the imaginary ellipse E by 1/4 circle is the final curve point _K4 , and from the outlet 2. It is installed so as to face the jet stream at a predetermined angle of depression.

According to this deflector plate 21, the radiation is actively diffused in the lateral direction as shown by the two-dot chain line arrow in FIG.
1, it is possible to achieve a greater force reduction effect due to greater lateral diffusion.

11 to 13 show a third embodiment of this invention, which is characterized by the structure of the direction changing surface.

The deflector plate 31 of this third embodiment includes:
A water dividing plate 32 extending in the front-rear direction is provided in the central part in a hanging shape, and the water dividing plate 32 is provided at the left and right side ends.
Side wall portions 34, 34 having the same height are provided in a hanging shape, and the water dividing plate 32 and the side wall portion 34 are formed so as to be continuous on the downstream side.

Between the water dividing plate 32 and the side walls 34, 34, the vertical cross-sectional shape of the jet flow divided into left and right sides (indicated by the two-dot chain arrow in FIG. a substantially U-shaped cubic curved deflection surface 33 that faces downward and has a downward cross-sectional shape;
33 is formed. The end point of this deflection surface 33 is set as the end point _K3 of 1/4 circle of the above-mentioned virtual ellipse E.

According to this deflector plate 31, compared to the deflector plates 11 and 21 described above, it is possible to achieve a greater direction change and force reduction effect.

Note that this invention is not limited to the above-mentioned explanation and illustrated examples, and its embodiments can be modified within a range that does not depart from the technical idea of this invention. For example, the deflector plate 11 is
Deflector plate 11A shown in FIG. 14 in plan view
The end edge on the end point side may be provided with a twist angle of about 70° in the horizontal direction with respect to the axis of the high-voltage iron pipe 1, as shown in FIG. In this case, although the dispersion of the jet water flux becomes uneven on the left and right sides, it is possible to further disperse the water flux and increase the energy-reducing effect.

Also, the final curve points are K ₁ , K ₂ , K ₃ in Figure 3
Of course, other points may also be used.

<Effects of the invention> The deflector for jet energy reduction according to this invention is
It has the above-mentioned configuration, and receives the discharged high-speed jet flow at the gentle curvature part, and the further downstream it goes, the more it changes its direction downward at an accelerated rate.
Vibration of the deflector plate due to collision of the jet flow and generation of reflected waves of the jet flow are prevented.

Therefore, by smoothly diverting the jet flow downward to shorten the distance to the landing point, and by diffusing the water flux laterally to significantly reduce the jet strength, the length of the deenergized pond can be reduced compared to the conventional method. This has the effect of reducing the time to about 60% of the previous example.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a deflector for jet energy reduction according to an embodiment of this invention, Fig. 2 is a plan view thereof, Fig. 3 is an explanatory view of the longitudinal cross-section of the deflection surface, and Fig. 4 is a tunnel waterway. 5 is a sectional view taken along line R-R in FIG. 2, FIG. 6 is a sectional view taken along line S-S in FIG. 2, and FIG. A side view of the deflector plate of the second embodiment, FIG. 8 is a view taken along the T arrow in FIG. 7, and FIG.
10 is a sectional view taken along line W-W in the figure, FIG. 10 is a view taken along arrow U in FIG. 7, FIG. 11 is a bottom view of the deflector plate of the third embodiment, and FIG. 12 is a sectional view taken along line XX in FIG. 13 is a sectional view taken along the Y-Y line in FIGS. 11 and 12, FIG. 14 is a plan view showing a modified example of the deflector of the first embodiment, and FIG. 15 is a conventional tunnel waterway sectional view. FIG. 16 is a vertical cross-sectional view showing a conventional flat deflector plate. 2... Discharge port, 10... Deflector for jet energy reduction, 11, 21, 31... Deflector plate,
13, 23, 33... Changing surface.

Claims (1)

[Scope of Claim for Utility Model Registration] A deflector for jet energy reduction, which is provided directly downstream of a discharge port to face the jet flow discharged from the discharge port, and is equipped with a deflection surface that changes the direction of the jet flow. A deflector for jet energy reduction, characterized in that the vertical cross-section of the jet flow in the flow direction of the deflection surface is formed in a curved shape that accelerates downward toward the downstream side.