JPH05256244A - Irregular pelton turbine - Google Patents

Abstract

PURPOSE:To prevent generation of interference of a jet in an upper surface of a runner bucket, in a 6-nozzle Pelton turbine. CONSTITUTION:Runner buckets 5 are arranged along a pitch circle 1a of a runner 1 by changing every other space of the runner buckets 5 from each other so as to alternately repeat the large and small spaces mutually between the runner buckets 5, and jet interference can be avoided without simultaneously generating a receiving end of a jet and a receiving start of the next jet, relating to the single runner bucket 5, thus to improve efficiency of a 6-nozzle Pelton turbine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anomalous type Pelton turbine in which the arrangement of runner buckets of a six-nozzle Pelton turbine is changed.

[0002]

2. Description of the Related Art The Pelton turbine is about 200 to 1800 m long.
Impulse water turbines applied to high heads, which used to be on the horizontal axis, but in recent years vertical axis machines have been adopted. The number of nozzles that can be attached to one runner is limited to two on the horizontal axis, but up to six on the vertical axis, making it possible to increase the capacity and speed. By controlling the number of units, it has become possible to operate with a small decrease in efficiency over an extremely wide output range. FIG. 2 is a plan view of a conventional 6-nozzle Pelton turbine. 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 branched through the branch pipe 2 through the inlet valve 3 is accelerated by the nozzle 4,
It becomes a jet, hits a runner bucket (not shown) of the runner 1, applies rotational force to the runner 1, and then falls naturally into the discharge channel. The jet ejected from the nozzle 4 is set so as to hit a runner bucket (not shown) at the contact point between the pitch circle of the runner 1 and the center of the jet.

FIG. 3 is a diagram showing an equal efficiency characteristic curve of the Pelton turbine of FIG. In the figure, the horizontal axis is the unit speed,
The vertical axis represents the unit flow rate. When the unit speed increases, 6
In nozzle operation, it interferes with the adjacent jets and causes a drop in efficiency. In the figure, the fact that the isoefficiency curves approach each other as the unit rotational speed increases and the unit flow rate increases indicates that the jet interference starts and the efficiency decreases drastically. Here, the unit rotational speed n ₁₁ = nD / √H,
The unit flow rate is Q ₁₁ = Q / D ² · √H, n is the rotational speed of the water turbine, D is the diameter of the pitch circle of the runner, H is the head, and Q is the flow rate per nozzle.

FIG. 4 shows one runner bucket with one
It is a figure which shows the change of the direction of the jet injected from each nozzle, (A) is a figure which shows the receiving start of the jet, (B) is a figure which shows the state of right angle inflow of the jet, (C) is the end of the jet receiving FIG. The jet 6 collides with the notch portion 8 of the runner bucket 5 and advances toward the inner diameter side of the runner bucket 5. When the runner bucket 5 rotates,
From the central part of the runner bucket 5, it advances at right angles to the pointed edge 7, that is, in the direction of the tangent to the pitch circle. When the runner bucket 5 further rotates, it collides from the inner diameter side of the runner bucket 5, advances toward the outer diameter side, and part of the water escapes from the cutout portion 8.
The same process is repeated for the next runner bucket 5. A conventional 6-nozzle Pelton turbine has six nozzles having the same diameter and about 16 to 22 runner buckets 5 having the same shape. Therefore, the phenomenon that occurs in each nozzle and bucket has occurred in any runner bucket 5.

[0005]

In the 6-nozzle Pelton turbine as described above, when the runner rotates at high speed, 1
When one runner bucket is receiving a jet, the timing of receiving the next jet is advanced, which causes jetting interference. In FIG. 4, the phenomenon of interference occurs when the water at the end of jet reception and the water at the beginning of the next jet collide with each other on the upper surface of the runner bucket, and when interference occurs, the efficiency of the turbine decreases. Was there. In order to avoid jet interference, it is necessary to ensure that the water at the end of one jet comes out of the bucket before it begins to receive the next jet.

It is an object of the present invention to provide a six-nozzle Pelton turbine, which is an irregular type Pelton turbine in which jet interference does not occur on the upper surface of the runner bucket.

[0007]

SUMMARY OF THE INVENTION In a six-nozzle Pelton turbine, the runner buckets are spaced apart from each other so that the runner buckets alternate in size with each other. By arranging along a circle, the above object is achieved.

Further, if the mutual intervals of the runner buckets are set to the standard interval corresponding to the output of the water turbine on the small interval side, it is suitable for preventing the jets from interfering with each other.

Further, the mutual spacing of the runner buckets is preferably 1.2 times as large on the large spacing side as on the small spacing side in order to prevent jets from interfering with each other.

[0010]

According to the present invention, the runner buckets are arranged so that the mutual intervals of the runner buckets are alternately repeated in magnitude. The jets do not interfere with each other on the upper surface of the runner bucket because they start receiving the jets.

[0011]

1 is a block diagram of a runner of an irregular type Pelton turbine according to an embodiment of the present invention. In the figure, there are two types of mutual intervals between the runner buckets, a large interval a and a small interval b, and the runner bucket mutual intervals are changed every other so that the large interval a and the small interval b are alternately repeated. The runner buckets 5 are arranged in the circumferential direction along the pitch circle 1a of the runner 1. When the small interval b is the standard interval of the runner bucket corresponding to the output of the Pelton turbine, the height of the runner bucket can be made lower than the standard to ensure the large interval a. If the large interval a is set to about 1.2 times the small interval b, the runner bucket 5 in front of the small interval b receives the jet, and the water flows out from the cutout portion 8 of the runner bucket 5 and then Jets come in, so jet interference can be avoided.

[0012]

As described above, according to the present invention, the mutual intervals of the runner buckets are repeated alternately in magnitude and small.
For one runner bucket, the end of receiving the jet and the start of receiving the next jet do not occur at the same time, and the jet interference can be avoided. In this way the efficiency of the 6 nozzle Pelton turbine can be increased.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a runner of an anomalous type Pelton turbine according to an embodiment of the present invention.

FIG. 2 is a plan view of a conventional 6-nozzle Pelton turbine.

3 is a diagram showing an equal efficiency characteristic curve of the Pelton turbine shown in FIG. 2;

FIG. 4 is a diagram showing a flow on the inner surface of a bucket of a jet of a Pelton turbine, FIG.
(B) is a diagram showing a right-angled flow state of the jet, and (C) is a diagram showing the end of receiving the jet.

[Explanation of symbols]

 1 runner 4 nozzle 5 runner bucket 6 jet 7 sharp edge 8 notch

Claims (3)

[Claims] 1. In a 6-nozzle Pelton turbine, the runner buckets are alternated one by one such that the runner buckets are alternately spaced so that the runner buckets alternate with each other. An irregular type Pelton turbine characterized by being arranged. 2. The irregular type Pelton turbine according to claim 1, wherein the mutual intervals of the runner buckets are standard intervals corresponding to the output of the hydraulic turbine on the small interval side. 3. The irregular-type Pelton turbine according to claim 1, wherein the runner buckets have a mutual interval of about 1.2 times on the large interval side and on the small interval side.