JP2003021036A - Impeller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impeller capable of preventing generation of noise by reducing pulsation. SOLUTION: In this impeller provided with a shroud 4, a crown 5 located on an upper side of the shroud 4 and a plurality of vanes 31 held between the shroud 4 and the crown 5, a crown side outlet port of the vane 31 is made more than 0.7 times as large as a shroud side outlet port.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impeller applied to a turbine or a turbine pump.

[0002]

2. Description of the Related Art As a conventional pump turbine, for example, one having a structure shown in FIG. 8 is known. That is, a runner cone 2 is provided at the lower end of a vertical main shaft 1, and a plurality of blades 3 are provided so as to surround the periphery of the runner cone 2. The blade 3 is sandwiched by a lower shroud 4 and an upper crown 5. A suction pipe 7 is provided below the runner cone 2. Also, the suction pipe 7
The height LD of the upper end is substantially equal to the runner diameter D2 (LD≈
You can think of it as D2).

[0003]

In such a conventional pump turbine, a partial load operation (60 to 7 of rated output) is performed.
If the operation is performed at 0%), the flow rate will decrease.
As shown in FIG. 9, the streamlines are biased toward the shroud side, and as a result, swirl swirling occurs in the suction pipe 7. There is a problem that the pressure drops sharply toward the center of the vortex, and due to this vortex, pulsation occurs in the flow and vibration and noise occur. In particular, there was a problem in that it collided with the inner wall surface of the upper portion of the suction pipe 7 and generated a large amount of noise.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an impeller capable of reducing pulsation and suppressing noise generation.

[0005]

The invention according to claim 1 is a blade provided with a shroud, a crown located above the shroud, and a plurality of blades sandwiched between the shroud and the crown. In the vehicle, the crown-side outlet port of the blade is 0.7 times or more the shroud-side outlet port.

In this impeller, since the flow rate on the crown side is increased as compared with the conventional case, the generation of vortices is prevented. By increasing the crown side outlet port to 0.7 times or more the shroud side outlet port as the expansion of the port, the hydraulic pulsation ΔH / He can be reduced to about 2%.

The invention according to claim 2 is a shroud,
In an impeller including a crown located above the shroud and a plurality of blades sandwiched between the shroud and the crown, a center side end diameter of the blade on the crown side is 0 of a runner diameter. It is characterized by being 4 times or more and 0.7 times or less.

In this impeller, the peripheral speed is reduced and the turning is reduced by bringing the central end of the blade on the crown side closer to the rotary shaft side than in the prior art. This suppresses the generation of vortices.

The invention according to claim 3 is a shroud,
In an impeller equipped with a crown located above the shroud, a plurality of blades sandwiched between the shroud and the crown, and a runner cone provided at the center of the rotation axis, the tip of the runner cone is a runner. It is characterized by protruding from the lower end of the shroud.

In this impeller, since the height of the runner cone is higher than in the conventional case, its tip is located lower than in the conventional case. For this reason, the vortex generation position in the suction pipe moves downward, and the generation of noise due to the collision of the vortex with the inner wall surface of the upper portion of the suction pipe is suppressed.

The invention according to claim 4 is a shroud,
In an impeller provided with a crown located above the shroud, a plurality of blades sandwiched between the shroud and the crown, and a runner cone provided at the center of a rotation axis, the runner cone has a truncated cone shape. A base end portion and a conical tip end portion that is continuous with the base end portion and has a larger side surface gradient than the base end portion, and the height of the base end portion (the height to the first waist break point) Is 1/3 or more of the height of the runner cone.

In this impeller, the boundary (first waist bending position) between the base end portion and the tip end portion of the runner cone is located lower than the conventional one. For this reason, the vortex generation position in the suction pipe moves downward, and the generation of noise due to the collision of the vortex with the inner wall surface of the upper portion of the suction pipe is suppressed.

The invention according to claim 5 is a shroud,
In an impeller provided with a crown located above the shroud, a plurality of blades sandwiched between the shroud and the crown, and a runner cone provided at the center of a rotation axis, fins are provided around the runner cone. It is characterized by being.

In this impeller, the generated swirling swirl flow is canceled by the fins of the runner cone.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a first embodiment of the present invention will be described with reference to the drawings. It should be noted that the same reference numerals are used for the same configurations as the conventional one, and the description thereof will be omitted.
FIG. 1 is a view corresponding to the XX cross section of FIG. In this figure, reference numeral 3 is a blade. Reference numeral 10 is an outlet port (effective passage width) indicated by the area of a circle inscribed in the adjacent blades 3. FIG. 2 shows the distribution of the outlet ports 10 from the crown 5 to the shroud 4. In the figure,
The dashed line is the conventional exit port distribution. As shown in the figure, the crown 5 side was 0.4 to 0.5 times as large as the shroud 4 side, but in this example, it is 0.7 times or more. That is, in this example, the outlet port on the crown 5 side is sufficiently large.

With this configuration, the flow rate to the crown 5 side does not decrease much compared to the conventional case even when the output is reduced. Specifically, as shown in FIG.
In the conventional flow rate indicated by the broken line, there was a dead water region where there was almost no flow rate on the crown 5 side, but in this example, it can be seen that a sufficient flow rate is obtained on the crown 5 side as indicated by the solid line. . Then, when the water pressure pulsation ΔH / He at this time was measured, it could be reduced to about 2%,
It was found that a good water pressure pulsation reduction drop was obtained.

Next, a second embodiment of the present invention will be described with reference to the drawings. It should be noted that the same reference numerals are used for the same configurations as the conventional one, and the description thereof will be omitted. In FIG. 4, reference numeral 31 is a blade. The blade 31 has a central end portion 31a on the crown 5 side as compared with the conventional blade shown by reference numeral 3.
Is closer to the center side. Specifically, the diameter D61 of the center-side end portion 31a of the blade 31 on the crown 5 side (the diameter of a circle inscribed in the center-side end portion of each blade 31 on the crown 5 side).
Is 0.4 to 0.7 times the runner diameter D2.

With this structure, the peripheral speed at the central end portion on the crown 5 side decreases and the turning becomes small. As a result, the generation of vortices can be suppressed and noise can be reduced.

Next, a third embodiment of the present invention will be described with reference to the drawings. The same components as those of the conventional one will be designated by the same reference numerals and the description thereof will be omitted. In FIG. 5, reference numeral 21 is a runner cone. Runner cone 21
Has a height dimension L1 larger than that of the conventional one, and protrudes below the lower end of the runner shroud 4.

With this structure, the vortex generation position in the suction pipe 7 moves downward, and the suction pipe 7
It is possible to suppress the generation of noise due to the collision of the vortex with the inner wall surface of the upper part of the.

Next, a fourth embodiment of the present invention will be described with reference to the drawings. The same components as those of the conventional one will be designated by the same reference numerals, and the description thereof will be omitted. In FIG. 6, reference numeral 22 is a runner cone. Runner cone 22
Includes a truncated cone-shaped base end portion 22a and a truncated cone-shaped tip end portion 22b which is continuous with the proximal end portion 22a and has a larger side surface gradient than the proximal end portion 22a. Height L2 of the base end 22a
Is larger than the conventional one, and the ratio L2 / L1 to the height L1 of the runner cone 22 is set to 1/3 or more. In addition, the code D7
Indicates the diameter of the position where the runner cone 22 is attached to the runner, and may be D7≈D6.

As described above, in this example, the boundary (the waist bending position) between the base end portion 22a and the tip end portion 22b of the runner cone 22 is located lower than the conventional one. Therefore, it is possible to suppress the generation of noise due to the vortex generation position in the suction pipe 7 moving downward and collision of the vortex with the inner wall surface of the upper portion of the suction pipe.

Next, a fifth embodiment of the present invention will be described with reference to the drawings. The same components as those of the conventional one will be designated by the same reference numerals and the description thereof will be omitted. In FIG. 7, reference numeral 32 is a runner cone according to this example. The runner cone 32 is provided with fins 32a around the periphery as shown in the figure.

With this structure, the generated vortex swirling flow is extinguished by the fins 32a, so that noise due to pulsation can be suppressed.

[0025]

As described above, the following effects can be obtained with the impeller of the present invention. According to the first and second aspects of the present invention, it is possible to prevent the generation of the vortex swirling flow, so that it is possible to prevent vibration and noise. According to the third and fourth aspects of the present invention, it is possible to prevent the generated vortex swirling flow from colliding with the inner wall surface of the upper portion of the suction pipe, so that vibration and noise can be suppressed. According to the invention of claim 5, the generated swirling flow is canceled out, so that vibration and noise can be prevented.

[Brief description of drawings]

FIG. 1 is a view showing an impeller shown as a first embodiment of the present invention and corresponds to a cross section taken along line XX of FIG.

FIG. 2 is a diagram showing a port distribution from the crown side to the shroud side in the same impeller.

FIG. 3 is a diagram showing a flow rate distribution from the crown side to the shroud side in the same impeller.

FIG. 4 is a diagram showing an outlet side end portion of a blade in an impeller shown as a second embodiment of the present invention.

FIG. 5 is a view showing a runner cone and an upper portion of a suction pipe used in an impeller shown as a third embodiment of the present invention.

FIG. 6 is a view showing a runner cone used in the impeller shown as the fourth embodiment of the present invention.

FIG. 7 is a perspective view of a runner cone used in the impeller shown as the fifth embodiment of the present invention.

FIG. 8 is a sectional view of a conventional impeller.

FIG. 9 is a diagram showing changes in streamlines.

[Explanation of symbols]

3 feathers 4 shrouds 5 crown 10 exit ports 21 runner corn 22 Lannacorn 22a base end 22b tip 31 feathers 32 runner corn 32a fin

Claims (5)

[Claims] 1. An impeller having a shroud, a crown located above the shroud, and a plurality of blades sandwiched between the shroud and the crown, wherein a crown-side outlet port of the blade is provided with a shroud. An impeller characterized by being 0.7 times or more larger than the side exit port. 2. An impeller provided with a shroud, a crown located above the shroud, and a plurality of blades sandwiched between the shroud and the crown, wherein a center side end portion of the blade on the crown side. The diameter is 0.4 times or more and 0.7 times or less the diameter of the runner. 3. An impeller provided with a shroud, a crown located above the shroud, a plurality of blades sandwiched between the shroud and the crown, and a runner cone provided at the center of a rotation axis, The tip of the runner cone is projected from the lower end of the shroud. 4. An impeller provided with a shroud, a crown located above the shroud, a plurality of blades sandwiched between the shroud and the crown, and a runner cone provided at the center of the rotation axis, The runner cone includes a truncated cone-shaped base end portion, and a truncated cone-shaped tip portion that is continuous with the base end portion and has a larger side surface gradient than the base end portion, and the height of the base end portion is An impeller that is 1/3 or more of the height of the runner cone. 5. An impeller provided with a shroud, a crown located above the shroud, a plurality of blades sandwiched between the shroud and the crown, and a runner cone provided at the center of a rotation axis, An impeller, wherein fins are provided around the runner cone.