JPH05164096A - Gas-liquid two-phase flow centrifugal pump - Google Patents

Abstract

PURPOSE:To enable efficient transfer even of a gas-liquid two-phase fluid with high void rate of 5 to 10%. CONSTITUTION:An impeller 22 to be provided in a casing 21 is constituted by a disc 24 in which a main shaft 23' is connected to its center, a plurality of main blades 25 mounted on the surface of the disc 24 and a plurality of auxiliary blades 26 mounted on the back of the disc 24. A plurality of balance holes 26 are also provided at the center of the disc 24. The gas phase of a gas-liquid two-phase fluid 29 supplied from a suction pipe 28 and reserved in a gas phase reservoir 30 is sent out through these balance holes 27 by a suction action of the auxiliary blades 26. By this, only the liquid phase is mainly sent out by the main blades 25 and then, the speed is increased by a speed increasing part 31 and the gas phase sent out by the auxiliary blades 26 is sucked and ejected from the casing 21 as the gas-liquid two-phase again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-liquid two-phase flow centrifugal pump, and more particularly to a centrifugal pump most suitable for transferring a gas-liquid two-phase fluid having a high void ratio of 5 to 10% or more. .

[0002]

2. Description of the Related Art An example of a conventional centrifugal pump is shown in FIGS.
Is shown in. In these figures, 1 is an impeller, 2
Spiral casing, 3 suction pipe, 4 diffuser, 5
Is the main axis. The impeller 1 has a main plate 6 fixed to a main shaft 5.
And side plates 7, and a plurality of blades 8 that are installed between them and that recede with respect to the rotation direction (solid arrow A) of the impeller 1 toward the outer periphery.

In the above structure, when the impeller 1 is rotated in the direction of the solid arrow A through the main shaft 5, the fluid passes through the suction pipe 3, the eyeball portion 9 of the impeller 1, the main plate 6, the side plates 7 and a plurality of them. It passes through a complex flow path 10 defined by a single vane 8. In this process, the fluid is urged by the plurality of blades 8 and then discharged through the spiral casing 2 and the diffuser 4.

[0004]

In the above-described conventional centrifugal pump, however, when a fluid of gas-liquid two-phase flow containing a gas phase (bubbles) is sucked in, the bubbles are as shown in FIGS. 5 and 6. First, the impeller 1 stays on the portion of the flow passage 10 where the pressure is low, that is, on the negative pressure surface 8 a of the impeller 8. Then, when the void ratio of the gas-liquid two-phase fluid becomes 5 to 10% or more, the bubbles stay and become the cavities 11, so that there is a problem that the gas-liquid two-phase fluid cannot be sent out.

The present invention has been made in order to solve the problems of the prior art, and it is possible to efficiently transfer even a gas-liquid two-phase fluid having a high void ratio of 5 to 10% or more. An object of the present invention is to provide a gas-liquid two-phase flow centrifugal pump.

[0006]

In order to solve the above-mentioned problems, the present invention relates to a centrifugal pump for gas-liquid two-phase flow, in which a main shaft is connected to the central part of a disk and the central part of the disk is located on the surface side of the disk. A plurality of main blades extending in the radial direction from around the part except is attached, and a plurality of sub-blades extending in the radial direction from the disk central portion are attached to the back surface side of the disk, and at the central portion of the disk. Indicates a plurality of balance holes.

[0007]

According to the above means, the vapor phase accumulated in the vapor phase retention portion formed in the center portion on the surface side of the disk which is the blade inlet portion is sent out through the balance hole by the suction action of the sub blade. . Therefore, mainly only the liquid phase is efficiently delivered by the main blade. Then, the delivered liquid phase becomes an accelerated flow at the outer peripheral portion of the disk, sucks the vapor phase sent by the sub-blades, becomes the gas-liquid two-phase again, and is discharged.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a longitudinal sectional view of a gas-liquid two-phase flow centrifugal pump according to this embodiment, and FIG. 2 is a front view of the centrifugal pump.

In these figures, according to the present embodiment,
The gas-liquid two-phase flow centrifugal pump includes an impeller 22 arranged in a spiral casing 21. This impeller 22
A disk 24 having a main shaft 23 connected to the central portion thereof, and a disk 24 extending radially from around the portion excluding the central portion of the disk to the vicinity of the outer peripheral portion of the disk 24 on the surface side of the disk 24 and at intervals of 45 ° in the circumferential direction. And 8 main blades 25 attached to each other, extending in the radial direction from the center of the disk to the vicinity of the outer circumference of the disk on the back surface side of the disk 24, and also mounted at an interval of 45 ° in the circumferential direction like the main blade 25. It is composed of eight auxiliary blades 26.

Further, in the central portion of the disk 24, eight balance holes 27 are formed on the same circumference and the auxiliary blade 2
The holes 6 are formed so as to be positioned one by one between the six. The suction pipe 28 is connected to the front surface side central portion of the casing 21 and opens at the front surface side central portion of the disk 24.

According to the structure described above, the gas-liquid two-phase fluid 29, which has entered the casing 21 of the centrifugal pump by the suction pipe 28, has its gas phase impeller by the centrifugal separation action of the main impeller 25 of the impeller 22. It stays in the vapor phase retention part 30 at the center of the front surface side of the disk 24 which is the inlet part.

However, the gas phase accumulated in the gas phase accumulating portion 30 is sucked out through the balance hole 27 as shown by an arrow in FIG. Therefore, mainly the liquid phase is efficiently delivered by the main blade 25. Then, the delivered liquid phase is
In the speed increasing part 31 on the outer peripheral part of the disk 24, the flow speed is increased, and due to the static pressure drop of the velocity head, the suction action of the gas phase (or gas-liquid two-phase fluid) delivered by the auxiliary blade 26 is increased,
As a result, the liquid phase and the gas phase merge in the casing 21,
The gas-liquid two-phase is discharged again.

[0013]

As described above, according to the centrifugal pump for gas-liquid two-phase flow according to the present invention, it is possible to deliver the liquid mainly in the main blade and the gas phase mainly in the sub-blade, Therefore, even if the void ratio is as high as 5 to 10% or more, the gas-liquid two-phase fluid can be efficiently delivered, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a gas-liquid two-phase flow centrifugal pump according to an embodiment of the present invention.

FIG. 2 is a front view of the centrifugal pump.

FIG. 3 is a schematic front view showing a conventional centrifugal pump.

FIG. 4 is a schematic vertical sectional view of the centrifugal pump.

FIG. 5 is a partial front view showing a staying state of a gas phase in the centrifugal pump.

FIG. 6 is a partial perspective view showing a staying state of the vapor phase.

[Explanation of symbols]

 21 casing 22 impeller 23 main shaft 24 disk 25 main blade 26 sub-blade 27 balance hole 28 suction pipe 29 gas-liquid two-phase fluid 30 gas-phase retention part 31 speed-up part

Claims (1)

[Claims] 1. A main shaft is connected to a central portion of a disk, and a plurality of main blades extending in a radial direction from around a portion excluding the central portion of the disk are attached to a front surface side of the disk, and a rear surface side of the disk is attached. Is a centrifugal pump for gas-liquid two-phase flow, characterized in that a plurality of auxiliary blades extending in the radial direction from the center of the disc are attached, and a plurality of balance holes are bored in the center of the disc.