JPH055478A - Branch pipe for pelton turbine - Google Patents

Abstract

PURPOSE:To provide a branch pipe for a Pelton turbine of high efficiency by decreasing a drift current to an external diameter side in a curved flow path in a curved pipe even when a nozzle approaches the branch pipe. CONSTITUTION:Current fairing plates 5, fixed with the upper and lower parts into a curved pipe part 2a of a branch pipe 2 and arranged parallelly to a flow path along the curved direction of the curved pipe part 2a to partition a curved flow path 2b in the curved pipe part 2a into a plurality of curved flow paths 2b1, 22, are provided to improve efficiency of a Pelton turbine by decreasing a drift current due to a curve in the respective flow paths and by jetting a jet almost uniformly from a total surface of nozzles 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a branch pipe for branching water into a plurality of nozzles of a Pelton turbine.

[0002]

2. Description of the Related Art The Pelton turbine is about 200 to 1800 m long.
It is applied to the high head of the
Up to 6 injection types can be used in the vertical axis to increase the capacity and speed, and by controlling the number of nozzles used, it is possible to operate with high efficiency over an extremely wide output range. The flow rate of the Pelton turbine is adjusted by inserting and removing the needle valve provided in the nozzle. In the Pelton turbine, the pressure water that is further branched by the branch pipe 2 after passing through the inlet valve 3 is accelerated by the nozzle 4 and becomes a jet that hits the bucket of the runner 1 and imparts rotational force to the runner 1, and then naturally flows to the discharge channel. To fall.

FIG. 4 is a plan view of a conventional vertical shaft Pelton turbine. Water passes through a water pressure pipe (not shown), flows in from the inlet of the vortex type branch pipe 2 through the inlet valve 3, and is branched at a branch portion having the number of nozzles-1. Immediately after the bifurcation, a sharp bend 2
a is provided, the water flow is deflected along the curved flow path 2b, flows into the nozzle 4, is jetted from the nozzle 4 to the runner.

FIG. 5 is a view showing the water flow in the curved flow passage in the curved pipe portion of the branch pipe of the Pelton turbine shown in FIG. Curved channel 2
In the case of b, even if it uniformly flows in at the inlet of the flow path, it bends at the outlet due to bending, so the flow is biased to the outside and the flow rate to the outside increases as indicated by the arrow. When such a non-uniform flow flows into the nozzle 4, a part that cannot be rectified due to the flow rectifying action of the flow path flows into the nozzle as a non-uniform flow, and flows into the runner as a non-uniform flow from the nozzle outlet. The jet injected from the nozzle 4 is set so as to hit the bucket at the contact point between the pitch circle of the bucket and the center of the jet. If a large flow rate of the jet flows in from the contact point on the outer diameter side, the Pelton turbine has an efficient performance. May be reduced.

[0005]

For this reason, in the past, the branch pipe 2 was made large, the distance from the branch portion to the nozzle 4 was lengthened, and a straight pipe was provided between them to straighten the flow. However, with this method, since the entire turbine becomes large, the manufacturing cost of the turbine increases, and as a result, the construction cost of the power plant increases.

An object of the present invention is to provide a highly efficient branch pipe for a Pelton turbine by reducing uneven flow to the outer diameter side in the curved flow path of the curved pipe portion even if the branch pipe and the nozzle are close to each other. ..

[0007]

In a branch pipe of a Pelton turbine that divides water into a plurality of nozzles through curved pipe portions, the pipes are vertically fixed in the curved pipe portion and flow along the bending direction of the curved pipe portion. The above object is achieved by providing a straightening plate which is arranged in parallel with the passage and partitions the curved flow passage of the curved pipe portion into a plurality of curved flow passages.

If two straightening vanes are provided in the curved pipe portion, it is suitable for straightening the water flow in the curved flow path of the curved pipe portion.

[0009]

According to the present invention, the upper and lower parts are fixed in the curved pipe portion immediately before the nozzle branching from the branch pipe to the respective nozzles, and are arranged in parallel with the flow path along the bending direction of the curved pipe portion. Since the straightening plate that partitions the curved flow passage into multiple curved flow passages is provided, the curved flow passage is divided into multiple curved flow passages, and the uneven flow between the inner diameter and the outer diameter is reduced, resulting in less uneven flow to the nozzle. Inflow. As a result, the jet ejected from the nozzle hits a predetermined position of the bucket.

[0010]

Embodiment 1 FIG. 1 is a plan view of a Pelton turbine having a branch pipe according to a first embodiment of the present invention. In FIG. 1, the same parts as those in FIG. 4 are designated by the same reference numerals. The configuration of the Pelton turbine is the same as that shown in FIG. FIG. 2 shows the first of the present invention.
FIG. 6 is a diagram showing the water flow in the curved pipe portion of the branch pipe according to the embodiment of FIG.
In the branch pipe 2 according to the first embodiment of the present invention, water is branched to each of the six nozzles 4 through the curved pipe portions 2a,
The upper and lower parts are fixed in the curved pipe portion 2a and are arranged parallel to the flow passage along the bending direction of the curved pipe portion 2a. The curved flow passage 2b of the curved pipe portion 2a is divided into two curved flow passages 2b ₁ and 2b ₂ . A partition plate 5 is provided. As a result, the curved flow path 2b is divided curved flow path 2b ₂ of curved flow path 2b ₁ and the inner diameter side of the outer diameter side and the two, internal and external drift in the flow paths is reduced.

[0011]Example 2  FIG. 3 is a curved pipe portion of a branch pipe according to a second embodiment of the present invention.
It is a figure which shows the water flow of. In FIG. 3, the same part as in FIG.
Are given the same reference numerals. In FIG. 3, ρ_iIs bent
Inner radius of channel 2b, ρ₀Is the outer diameter side half of the curved pipe portion 2a
Diameter, ρ_s1Is the radius of the outer diameter side straightening plate, ρ_s2Is the inner rectifying plate
Is the radius. In FIG. 3, when there are two straightening vanes 5, ρ
_s1= (Ρ₀ ²ρ_i)^1/3, Ρ_s2= (Ρ₀ρ_i ²)^1/3Degree
Just take a degree. In addition, when there is one straightening plate 5, ρ_s=
(Ρ₀ρ_i)^1/2It should be about. Two straightening vanes 5
At this time, the curved flow passage 2b has three curved flow passages 2b.₁, 2
b₂, 2b₃As it is divided into
The uneven flow of is further reduced compared to the case where there is only one rectifying plate 5.
It

[0012]

According to the present invention, the upper and lower portions are fixed in the curved pipe portion immediately before the nozzle branching from the branch pipe to the respective nozzles, and are arranged in parallel with the flow path along the bending direction of the curved pipe portion. Since a straightening plate was installed to partition the curved flow passage of the pipe into multiple curved flow passages, the curved flow passage is divided into multiple flow passages and rectified to reduce uneven flow due to bending, and the curved pipe portion of the branch pipe. Since a water flow whose flow rate is distributed almost evenly over the entire surface is supplied from the nozzle, the jet injected from the nozzle hits the runner as designed, so that the efficiency of the Pelton turbine can be improved. In addition, if two straightening vanes are provided in the curved pipe portion, the uneven flow inside and outside each flow path is further reduced as compared with the case where there is only one straightening vane, and jets are jetted almost uniformly from the entire surface of the nozzle. , The efficiency of the Pelton turbine can be improved.

[Brief description of drawings]

FIG. 1 is a plan view of a Pelton turbine equipped with a branch pipe according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the water flow in the curved pipe portion of the branch pipe according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a water flow in a curved pipe portion of a branch pipe according to a second embodiment of the present invention.

FIG. 4 is a plan view of a conventional vertical shaft Pelton turbine.

5 is a diagram showing the water flow in the curved pipe portion of the branch pipe of the Pelton turbine shown in FIG. 4;

[Explanation of symbols]

1 runner 2 branch pipe 2a curved pipe part 2b curved flow channel 2b ₁ curved flow channel 2b ₂ curved flow channel 2b ₃ curved flow channel 4 nozzle 5 straightening plate

Claims (1)

Claim: What is claimed is: 1. In a branch pipe of a Pelton turbine that branches water through a plurality of nozzles through curved pipe portions, the upper and lower parts are fixed inside the curved pipe portion, and the pipes are bent along the bending direction of the curved pipe portion. A branch pipe of a Pelton turbine, wherein a straightening plate is provided in parallel with the flow channel to partition the curved flow channel of the curved pipe section into a plurality of curved flow channels. 2. A branch pipe for a Pelton turbine according to claim 1, wherein two straightening vanes are provided in the curved pipe portion.