JPH1172077A - Cylinder gate type hydraulic turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the specified maximum output of a cylinder gate type hydraulic turbine by providing an allowance to the rated output of the hydraulic turbine so as to compensate for the shortage of the output due to error of workmanship. SOLUTION: In a cylinder gate type hydraulic turbine which is provided with a fixed guide vane 4 and a cylinder gate 5 to adjust flow rate by varying the width of a water conducting channel in a flow path leading from a casing 2 to a runner 1, the mounting angle of the fixed guide vane 4 is set at an angle equivalent to the maximum output of the hydraulic turbine, and the flow path width of a cylinder gate 5 at full opening is set slightly larger, with an allowance provided, than that equivalent to the maximum output of the hydraulic turbine. By this, when the maximum output in actual operation is lower than a design value due to an error of workmanship, the opening of the cylinder gate 5 is increased to increase the width of the flow channel larger than that equivalent to the maximum output of the hydraulic turbine. Thus the amount of a shorted output is compensated for so as to secure the specified maximum output of the hydraulic turbine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder gate type turbine applied to a reaction turbine such as a Francis turbine and a Kaplan turbine.

[0002]

2. Description of the Related Art As a cylinder gate type water turbine described above,
A fixed guide vane and a cylinder gate (flow rate adjustment ring) for adjusting the width of the passage are installed in the flow passage leading from the inner peripheral side of the casing to the turbine runner, and the opening of the cylinder gate is maintained without changing the blade angle of the guide vane. A configuration in which the flow rate is adjusted in accordance with the load and the head variation by adjustment has already been proposed and is known from Japanese Patent Publication No. 7-18399.

In the above-mentioned cylinder gate type turbine, the mounting angle of the guide vanes (between the chord line of the guide vanes and the radial direction passing through the center of the runner) is set so that the maximum output and efficiency can be obtained when the cylinder gate is fully opened. Angle) is set and fixed so as to obtain an optimum water inflow angle with respect to the runner, and the flow rate adjustment with respect to the load variation is performed by changing the opening degree of the cylinder gate. As a result, the vane angle of the guide vanes does not change even at a low load compared to a conventional water turbine in which the guide vanes are changed by changing the opening degree of the guide vanes (the water inflow angle to the runner is optimally maintained). Therefore, the rate of efficiency decrease is smaller than that of a conventional turbine having a guide vane with adjustable blade opening, so that high turbine efficiency from low output to high output can be obtained.

[0004]

By the way, production errors (dimensional accuracy, blade angle, blade surface undulations, etc.) are unavoidable to some extent in water turbine products, and cavitation and the like occur during actual operation. For this reason, especially in a reaction turbine such as a Francis turbine and a Kaplan turbine, the above-described manufacturing error greatly affects the operation characteristics of the turbine, and the output during actual operation is lower than the rated value, and a predetermined turbine output cannot be obtained. It may be.

Therefore, even if the above-described cylinder gate type turbine is designed and manufactured so that the maximum turbine output and efficiency can be obtained when the guide vanes are mounted at the fully opened state of the cylinder gate, As described above, the turbine output in actual operation may fall below the rated value due to a manufacturing error or the like, and a predetermined maximum turbine output may not be secured.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a margin for a flow rate adjustment range in advance with respect to a rated output, and to compensate for a shortage of output caused by a manufacturing error or the like, thereby realizing an actual operation. It is an object of the present invention to provide a cylinder-gate type turbine that can attain a predetermined maximum turbine output at times.

[0007]

According to the present invention, in order to achieve the above object, a cylinder-gate type water turbine is configured as follows. (1) The mounting angle of the fixed guide vanes is set to an angle equivalent to the maximum turbine output, and the flow path width when the cylinder gate is fully opened is given more margin than the flow path width (design value) equivalent to the maximum turbine output. It is set large (claim 1).

According to the above configuration, when the maximum output of the turbine during actual operation is lower than the design value due to a manufacturing error or the like, the opening of the cylinder gate is adjusted to be increased to increase the flow path width. By further expanding the output of the turbine wheel, the shortage of the output can be compensated and a predetermined maximum turbine output can be secured. (2) Set the passage width when the cylinder gate is fully open to the passage width equivalent to the maximum turbine output, and set the mounting angle of the fixed guide vane smaller than the angle equivalent to the maximum turbine output (set the vane angle of the guide vane to the runner (Approaching in the radial direction passing through the center).

If the mounting angle of the fixed guide vanes is set as described above, the maximum turbine output can be obtained in a state where the degree of opening of the cylinder gate is slightly lower than the full opening in terms of design. Therefore, even under conditions where the turbine output during actual operation is lower than the rated value due to manufacturing errors, etc., by adjusting the opening of the cylinder gate further toward full opening, the output shortage due to manufacturing errors etc. can be reduced. By compensating, a predetermined maximum turbine output can be secured.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to each embodiment shown in FIGS. 1 and 2 (a cylinder gate turbine for a Francis turbine). Embodiment 1 FIGS. 1 (a) and 1 (b) show an embodiment corresponding to claim 1. FIG. In the figure, 1 is a runner of a Francis turbine, 2 is a casing, 3 is a flow path (a flow path is defined between the upper cover and the lower cover of the turbine) from the casing 2 to the outer peripheral surface of the runner 1, 4. Are fixed guide vanes which are arranged in the flow passage 3 at regular intervals in the circumferential direction;
Is a cylinder gate (a hollow annular sleeve that is arranged coaxially with the runner 1 and is movable in the up-down direction) that protrudes and descends from below into the flow path 3 and changes the flow path width (height).
An airfoil slit into which the guide vane 4 is fitted is open at the upper end surface.) Reference numeral 5a denotes a driving portion of the cylinder gate 5.

Here, the mounting angle γ of the fixed guide vane 5
Is defined as an inclination angle formed by a radial line p passing through the center O of the runner 1 and a chord line q of the guide vane 5, and in this embodiment, as shown in FIG. The angle γ1 is set to the inflow angle corresponding to the maximum turbine output (the angle at which the optimal water inflow angle with respect to the runner 4 in the maximum output operation state).

On the other hand, the flow path width (flow path sectional height in the drawing) A of the flow path 3 corresponding to the fully open position of the cylinder gate 5 is:
The flow path width (design value) B is set to be slightly larger (A> B) corresponding to the maximum turbine output, and the cylinder gate 5 is configured to be able to move from fully open to fully closed. With such a configuration, under ideal conditions with no manufacturing error or the like, the cylinder gate 5 can be used during actual operation of the water turbine.
Is adjusted to a position where the flow path width becomes B, the maximum turbine output can be obtained as rated. On the other hand, the turbine efficiency is reduced due to a manufacturing error or the like. Therefore, even if the opening of the cylinder gate 5 is opened to the opening corresponding to the flow path width B during the actual operation, the turbine output becomes the predetermined maximum output. When the value is less than the rated value, the opening degree of the cylinder gate 5 is further increased from the above operating position to increase the cross-sectional width of the flow passage 3 from B to A, thereby compensating for the output shortage due to a manufacturing error or the like. The maximum turbine output of the street can be secured.

Embodiment 2 FIGS. 2A and 2B show an embodiment corresponding to claim 2. FIG. In this embodiment, the passage width of the passage 3 corresponding to the fully opened position of the cylinder gate 5 is set to the passage width B (the passage width corresponding to the maximum turbine output) described in the first embodiment. On the other hand, the mounting angle γ2 of the fixed guide vane 5 is the angle γ1 corresponding to the maximum turbine output (FIG. 1).
(see (b)) is set to be slightly smaller (γ2 <γ1), that is, the effective flow path section restricted between the adjacent guide vanes 5 is slightly enlarged as compared with FIG.

With such a configuration, under ideal conditions with no manufacturing error or the like, the rated maximum turbine output at the adjustment position (flow path width C) in which the opening of the cylinder gate 5 is slightly lower than the full opening is obtained. can get. On the other hand, the efficiency of the turbine decreases due to a manufacturing error or the like. Therefore, even if the opening of the cylinder gate 5 is opened to the opening corresponding to the adjustment position (flow path width C) during actual operation, the turbine is When the output is lower than the predetermined maximum output, the cylinder gate 5 is further opened from the above-mentioned opening degree (flow path width C) to the fully open position (flow path width B), thereby producing an output due to a manufacturing error or the like. The predetermined maximum turbine output can be secured by compensating for the shortage.

[0015]

As described above, according to the present invention,
Due to manufacturing errors of the cylinder gate type turbine, the efficiency of the turbine during actual operation is lower than the design value, and therefore the output does not reach the rated maximum turbine output even if the cylinder gate is opened to the opening equivalent to the maximum output Even in such a situation, by adjusting the opening degree of the cylinder gate, which has a margin in advance in the flow path width adjustment range, in a direction to further increase,
A predetermined maximum turbine output can be ensured by compensating for the output shortage caused by manufacturing errors and the like.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a cylinder gate type water turbine corresponding to a first embodiment of the present invention, wherein (a) is a longitudinal sectional view, and (b) is a transverse sectional view of a main part.

FIG. 2 is a schematic configuration diagram of a cylinder gate type water turbine corresponding to a second embodiment of the present invention, where (a) is a longitudinal sectional view and (b) is a transverse sectional view of a main part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Runner 2 Casing 3 Flow path 4 Fixed guide vane 5 Cylinder gate A, B, C Flow path width γ1, γ2 Mounting angle of guide vane

Claims (2)

[Claims] In a cylinder gate type turbine having a fixed guide vane and a cylinder gate for adjusting a flow rate in a flow passage leading from a casing to a runner, an attachment angle of the fixed guide vane is set to an angle corresponding to a maximum turbine output. A cylinder gate type water turbine characterized in that the flow channel width when the cylinder gate is fully opened is set to be larger than the flow channel width corresponding to the maximum turbine output. 2. A cylinder gate type water turbine having a fixed guide vane and a cylinder gate for adjusting a flow rate in a flow path from a casing to a runner. A cylinder gate type water turbine wherein the road width is set and a fixed guide vane mounting angle is set to be smaller than an angle corresponding to a maximum water turbine output.