JP3537797B2 - Water injection method for centrifugal compressor and centrifugal compressor having water injection function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water injection method for cooling an intake air, an intermediate cooling, and the like of a centrifugal compressor used in a small gas turbine and the like, and a structure thereof.

[0002]

2. Description of the Related Art When water is injected into a compressor in order to improve efficiency and increase output by suction cooling and intermediate cooling of the compressor, drain attack (damage to the compressor due to large water droplets), erosion, and the like are avoided. Therefore, atomization of the injection water must be reduced. In particular, when water is injected into a centrifugal compressor, a water injection function must be added to a space whose structure is limited.

For example, Japanese Patent Application Laid-Open No. 7-127600 describes a structure in which a water injection nozzle is provided on a casing wall on a core plate side of an impeller in a multistage centrifugal compressor. Japanese Patent Application Laid-Open No. 10-18976 discloses a multi-stage centrifugal compressor configured to spray water to a suction pipe and a return flow path of the compressor.

Japanese Patent Application Laid-Open No. 2000-97197 describes a water injection system of a centrifugal compressor in which a water injection nozzle by gas atomizing is installed inside a suction pipe or a casing of the compressor. Also, Japanese Patent Application Laid-Open No. 2000-1
Japanese Patent No. 20595 discloses a multi-stage centrifugal compressor in which a water injection nozzle is attached to a stagnation portion formed near a return flow path that guides a flow of working gas from a preceding impeller to a next-stage impeller. Has been described.

[0005]

The above-mentioned Japanese Patent Application Laid-Open No. 7-12 / 1995
In the technology described in Japanese Patent No. 7600, it is necessary to form the water injection nozzle into a nozzle shape such that water is sprayed (fine particles), and the direction of the water injection nozzle is such that water droplets directly collide with the core plate of the impeller. It is necessary to be not oriented. In the technique disclosed in Japanese Patent Application Laid-Open No. Hei 10-18976, for example, when water is sprayed in the return flow path, the flow rate of the working gas is slow, the water is not atomized, and there is a problem of generation of drainage and erosion.

In the technique disclosed in Japanese Patent Application Laid-Open No. 2000-97197, an atomizing air pipe is required, and the arrangement of the injection nozzle is structurally difficult. Also, a large amount of atomizing air (for example, about 100 to 3 to spray 1 liter of water).
By extracting air (requiring 00 liters of air), the air compression power is increased (the compressed air is used for atomization). Also, JP-A-2000-1205
In the technique disclosed in Japanese Patent Publication No. 95, a nozzle can be arranged in the stagnation portion, but the flow rate of the working gas is low and drain occurs. In addition, it is difficult to secure a space for atomizing water, and it is necessary to increase the injection pressure with a one-fluid nozzle, which causes problems such as an increase in liquid compression power and wear of the injection holes.

The present invention has been made in view of the above points, and an object of the present invention is to utilize a structure of a centrifugal compressor to perform a simple modification or replacement of a diffuser, an impeller, and a shaft, thereby obtaining a two-fluid nozzle. The use of airflow energy to achieve atomization of spray without the use of air, etc., eliminates the need for drain collection, avoids erosion, etc., and also allows the centrifugal structure to easily add a water injection function due to its structure An object of the present invention is to provide a method for injecting water into a compressor and a centrifugal compressor having a function of injecting water.

[0008]

In order to achieve the above object, a method for injecting water into a centrifugal compressor according to the present invention comprises a rotatable shaft supported in a casing and an axial direction of the shaft. An impeller (impeller) rotating with the shaft, the impeller constituting at least one compression stage provided;
Water is injected for the purpose of intermediate cooling or the like to a centrifugal compressor having a diffuser fixedly installed outside the impeller outlet, a gap between the casing and the impeller, and a gas flow path formed by the diffuser in the casing. In the method, water is injected at a location where the gas flow rate of the diffuser is high from the gas flow rate distribution in the diffuser, and the jetted water is atomized using the energy of the air flow (FIGS. 5, 6, and 7). 9 and 10).

The method of the present invention also includes a rotatable shaft supported in a casing, an impeller rotating with the shaft, the impeller comprising at least one compression stage disposed in the axial direction of the shaft. Water is injected for the purpose of intermediate cooling or the like to a centrifugal compressor having a diffuser fixedly installed outside the impeller outlet, a gap between the casing and the impeller, and a gas flow path formed by the diffuser in the casing. The method is characterized in that water is jetted by a diffuser, and the jetted water collides with a plate-shaped member (for example, a flat plate) provided in a gas flow path on the diffuser to atomize the water (see FIG. 8).

The method of the present invention also includes a rotatable shaft supported in a casing, an impeller rotating with the shaft, the at least one compression stage disposed in the axial direction of the shaft. Water is injected into a centrifugal compressor having a diffuser fixedly installed outside the impeller outlet, a gap between the casing and the impeller, and a gas flow path formed by the diffuser in the casing for the purpose of intake cooling and the like. The method is characterized in that water is jetted from a shaft on the impeller inlet side, and the jetted water is accelerated and atomized using the increase in relative speed due to rotation (see FIG. 11).

[0011] The method of the present invention also includes a rotatable shaft supported in a casing, an impeller rotating with the shaft, the impeller comprising at least one compression stage disposed in the axial direction of the shaft. Water is injected for the purpose of intermediate cooling or the like to a centrifugal compressor having a diffuser fixedly installed outside the impeller outlet, a gap between the casing and the impeller, and a gas flow path formed by the diffuser in the casing. The method is characterized in that water is injected from the middle stage of the impeller, and the injected water is accelerated and atomized using the increase in relative speed due to rotation (see FIG. 12).

The method of the present invention also includes a rotatable shaft supported in a casing, an impeller rotating with the shaft, the impeller comprising a plurality of compression stages disposed in the axial direction of the shaft, and an impeller outlet. A method of injecting water for the purpose of intermediate cooling or the like into a multi-stage centrifugal compressor having a diffuser fixed and installed outside, a gap between a casing and an impeller, and a gas flow path formed by the diffuser in the casing. Is characterized in that water is injected from a shaft on the impeller inlet side of a high-pressure stage, and the jetted water is accelerated and atomized by utilizing the increase in relative speed due to rotation (see FIG. 13).

[0013] A centrifugal compressor having a water injection function according to the present invention includes a rotatable shaft supported in a casing,
An impeller rotating with the shaft, the impeller constituting at least one compression stage disposed in the axial direction of the shaft;
In a centrifugal compressor including a diffuser having guide vanes fixedly installed outside an impeller outlet, and a gap between a casing and an impeller and a gas flow path formed by the diffuser in the casing, a vane side surface of the diffuser A water injection hole is provided on the side where the gas flow velocity is high, and water is injected from the water injection hole substantially at right angles to the gas flow to atomize the injected water with the energy of the gas flow (FIG. 5, See FIG. 6).

Further, the centrifugal compressor of the present invention comprises a rotatable shaft supported in a casing and at least one compression stage disposed in the axial direction of the shaft.
A centrifugal compressor including an impeller that rotates with the shaft, a diffuser having guide vanes fixedly installed outside the impeller outlet, and a gap between the casing and the impeller and a gas flow path formed by the diffuser in the casing. In the above, a water injection hole is provided on the side where the gas flow velocity is high on the flow path between the diffuser blades, and the water is injected from the water injection hole to atomize the injection water with the energy of the air flow. (See FIG. 7).

Further, the centrifugal compressor of the present invention comprises a rotatable shaft supported in a casing, and at least one compression stage disposed in the axial direction of the shaft.
A centrifugal compressor including an impeller that rotates with the shaft, a diffuser having guide vanes fixedly installed outside the impeller outlet, and a gap between the casing and the impeller and a gas flow path formed by the diffuser in the casing. In the above, a water injection hole is provided on the side surface of the blade portion of the diffuser, and a plate-like member (for example, a rectifying plate and a guide plate) is provided at a water injection position between the blade portions on the diffuser (for example,
(A flat plate) is provided, and water is injected from a water injection hole to collide with a plate-shaped member to atomize the injected water (see FIG. 8).

Further, the centrifugal compressor of the present invention comprises a rotatable shaft supported in a casing and at least one compression stage disposed in the axial direction of the shaft.
A centrifugal compressor including an impeller that rotates with the shaft, a diffuser having guide vanes fixedly installed outside the impeller outlet, and a gap between the casing and the impeller and a gas flow path formed by the diffuser in the casing. In the above, on the flow path between the vanes of the diffuser, a rod-shaped member having a water injection hole on the side is erected, and water is injected from the water injection hole to atomize the injected water with the energy of the airflow. (See FIGS. 9 and 10). In this case, it is preferable that the rod-shaped member having the water injection hole is rotatable, and the direction of the injection can be arbitrarily set with respect to the gas flow. Further, a rod-shaped member having a water injection hole may be fixedly installed so that water can be injected to the side where the gas flow rate is high.

Further, the centrifugal compressor of the present invention comprises a rotatable shaft supported in a casing and at least one compression stage disposed in the axial direction of the shaft.
A centrifugal compressor including an impeller that rotates with the shaft, a diffuser having guide vanes fixedly installed outside the impeller outlet, and a gap between the casing and the impeller and a gas flow path formed by the diffuser in the casing. , An injection water passage is provided in the shaft, and at least one water injection hole for injecting water passing through the injection water passage is provided on a shaft side surface on the impeller inlet side, and water is injected from the water injection hole to the impeller inlet to rotate. It is characterized in that the injection water is accelerated and atomized by utilizing the increase in the relative speed due to (see FIG. 11).

Further, the centrifugal compressor of the present invention comprises a rotatable shaft supported in a casing, and at least one compression stage disposed in the axial direction of the shaft.
A centrifugal compressor including an impeller that rotates with the shaft, a diffuser having guide vanes fixedly installed outside the impeller outlet, and a gap between the casing and the impeller and a gas flow path formed by the diffuser in the casing. , An injection water passage is provided in the shaft, at least one water injection hole for injecting water passing through the injection water passage is provided in the middle stage of the impeller, and water is injected from the water injection hole to the middle stage of the impeller, and the relative speed by rotation is provided. This is characterized in that the injection water is accelerated and atomized by utilizing the rise of the pressure (see FIG. 12).

Also, the centrifugal compressor of the present invention comprises a rotatable shaft supported in a casing, an impeller rotating with the shaft, forming a plurality of compression stages disposed in the axial direction of the shaft. In a multi-stage centrifugal compressor having a diffuser having guide vanes fixedly installed outside the impeller outlet and a gap between the casing and the impeller and a gas flow path formed by the diffuser in the casing, injection into a shaft is performed. A water passage is provided, and at least one water injection hole for injecting water that has passed through the injection water passage is provided on a shaft side of the impeller inlet side of the high-pressure stage. It is characterized in that the injection water is accelerated and atomized by utilizing the increase in speed (see FIG. 13).

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments and can be implemented with appropriate modifications. . FIG. 1 shows an example of a gas turbine using a centrifugal compressor. FIG. 1 shows an example in which a two-stage centrifugal compressor is used. As shown in FIG. 1, the taken air (intake air) is introduced into an impeller 12 at a low pressure stage in the centrifugal compressor 10. The impeller 12, a high-pressure stage impeller 14, which will be described later, and a turbine 16 are attached to a shaft 18 and rotate together with the shaft 18. 2
0 is a bearing. The air compressed by the rotating impeller 12 enters the return passage 24 through the diffuser 22 fixed outside the outlet of the impeller 12, and is introduced into the high-pressure stage impeller 14. The air further compressed in the high pressure stage is burned in a combustor 28 together with fuel injected from a fuel nozzle 26, and the high temperature and high pressure combustion gas
Rotate 6.

2 and 3 show examples of the structure of a centrifugal compressor. A diffuser 22 having a protruding guide blade portion 30 is fixed to the outside of the outlet (the downstream portion) of the impeller 12 that rotates together with the shaft 18. In FIG. 2, the directions of rotation of the impeller 12 and the shaft 18 and the direction of the gas flow in the diffuser 22 are indicated by arrows. When the impeller rotates in the same direction as in FIG. 2, the velocity distribution of the gas flow in the diffuser is an analysis result as shown in FIG.
The result of the numerical analysis shows the tendency of the gas flow rate distribution of the diffuser.

FIGS. 5 and 6 show a main part of a centrifugal compressor having a water injection function according to the first embodiment of the present invention. As shown in FIGS. 5 and 6, a water injection hole 32 is provided by making a hole in the side surface of the guide vane 30 of the diffuser 22, and water is injected from the water injection hole 32 substantially perpendicularly to the gas flow. The jet water from the water jet holes 32 is miniaturized using the energy of the airflow. In this case, in consideration of the gas flow rate distribution of the diffuser described above, it is desirable that the position of the water injection hole 32 be on the side where the gas flow rate is high. In this embodiment,
All that is required is to make a hole in the diffuser, which is a simple method.

FIG. 7 shows a main part of a centrifugal compressor having a water injection function according to a second embodiment of the present invention. FIG.
As shown in FIG. 5, a water injection hole 36 is provided by making a hole from the back surface on the flow path 34 between the guide blades 30 of the diffuser 22, and water is injected from the water injection hole 36 into the gas flow. The jet water from the water jet holes 36 is atomized using the energy of the airflow. Also in this case, in consideration of the gas flow rate distribution of the diffuser described above, it is desirable that the position of the water injection hole 36 is on the side where the gas flow rate is high. The present embodiment is also a simple method that only requires making a hole in the diffuser.

FIG. 8 shows a main part of a centrifugal compressor having a water injection function according to a third embodiment of the present invention. FIG.
As shown in FIG. 7, a water injection hole 32 is provided by making a hole in the guide blade 30 side surface of the diffuser 22, and water is injected from the water injection hole 32 substantially at right angles to the gas flow. The jet water from the water jet holes 32 is atomized using the energy of the airflow. In addition, a flat plate 38 serving also as a rectifying plate and a guide plate is installed on the flow path 34 between the guide blade portions 30 of the diffuser 22, and large droplets that have not been atomized collide with the wall surface of the flat plate 38 to be atomized. I do. Other configurations are the same as those in the first embodiment.

FIGS. 9 and 10 show a main part of a centrifugal compressor having a water injection function according to a fourth embodiment of the present invention. As shown in FIGS. 9 and 10, the water injection holes 4 are provided on the side surfaces on the flow path 34 between the guide vanes 30 of the diffuser 22.
A rod-shaped member (perforated bar) 42 having 0 is erected and water is injected from the water injection hole 40 into the gas flow. The jet water from the water jet holes 40 is atomized using the energy of the airflow. It is desirable that the rod-shaped member 42 having the water injection hole 40 be configured to be rotatable so that the direction of water injection can be set arbitrarily, such as parallel to the gas flow or at a right angle. Further, the rod-shaped member 42 having the water injection hole 40 may be fixed and installed. In this case, it is preferable that the direction is such that water can be injected to the side where the gas flow rate is high. Other configurations etc.
This is the same as in the case of the embodiment.

FIG. 11 shows a cross section of a main part of a centrifugal compressor having a water injection function according to a fifth embodiment of the present invention. As shown in FIG. 11, a shaft 18 is used to inject water at the inlet of the impeller 12 to cool the compressor.
A water passage 44 is provided in the longitudinal direction of the inside, and a hole is formed in the side surface of the shaft 18 on the inlet side of the impeller 12 to form a water injection hole 46 so that the water passing through the water passage 44 can be injected from the water injection hole 46. . The water injection holes 46 can be provided radially in the circumferential direction of the side surface of the shaft 18, for example, and the number thereof is arbitrary. In FIG. 11, two water injection holes 46 are provided as an example. The relative speed of the jet water jetted from the water jet holes 46 is increased by the rotation of the shaft 18 and the impeller 12, and the atomization is promoted.

FIG. 12 shows a cross section of a main part of a centrifugal compressor having a water injection function according to a sixth embodiment of the present invention. As shown in FIG. 12, in order to inject water in the middle stage of the impeller 12 and perform intermediate cooling of the compressor, a spray water passage 44 is provided in the longitudinal direction in the shaft 18, and a hole is formed in the middle stage of the impeller 12 through the shaft 18. Open the water injection hole 48,
The water that has passed through the injection water passage 44 can be injected from the water injection hole 48. The water injection hole 48 is, for example, the impeller 12
It can be provided radially in the circumferential direction of the middle stage, and the number is arbitrary. In FIG. 12, two water injection holes 48 are provided as an example. The relative velocity of the jet water jetted from the water jet holes 48 is increased by the rotation of the impeller 12, and the atomization is promoted.

FIG. 13 shows a cross section of a main part of a centrifugal compressor having a water injection function according to a seventh embodiment of the present invention. As shown in FIG. 13, in a multi-stage centrifugal compressor (in FIG. 13, as an example, a two-stage centrifugal compressor), water is injected at a high-pressure stage inlet to perform intermediate cooling of the compressor. A water injection passage 44 is provided in the longitudinal direction, and a hole is formed in the side surface of the shaft 18 on the inlet side of the impeller 14 of the high pressure stage to form a water injection hole 50, so that water passing through the water injection passage 44 can be injected from the water injection hole 50. I do. The water injection holes 50 can be provided radially in the circumferential direction of the side surface of the shaft 18, for example, and the number thereof is arbitrary. In FIG.
As an example, two water injection holes 50 are provided. The relative speed of the jet water jetted from the water jet holes 50 is increased by the rotation of the shaft 18 and the impeller 12, and the atomization is promoted.

[0029]

As described above, the present invention has the following advantages. (1) Since water is injected by the diffuser of the centrifugal compressor, atomization of the spray can be achieved using the energy of the air flow without using a two-fluid nozzle or the like, and the arrangement of water injection holes is easy due to its structure. It is. (2) By arranging the water injection holes in consideration of the gas flow velocity distribution of the centrifugal compressor and the diffuser, atomization of the spray using the energy of the air flow can be further promoted. (3) In the case where a plate-like member such as a flat plate is provided in the diffuser, droplets that have not been atomized from the water injection holes can collide with the wall surface of the flat plate to be atomized. (4) By providing a water injection hole in the shaft and injecting water at the inlet of the impeller for cooling the compressor intake air, atomization of the injected water is promoted by an increase in relative speed due to rotation. (5) By providing a water injection hole in the middle stage of the impeller and injecting water for the intermediate cooling of the compressor, atomization of the injected water is promoted by an increase in relative speed due to rotation. (6) In a multistage centrifugal compressor, a water injection hole is provided in a shaft of a high pressure stage inlet for water injection at a high pressure stage inlet for intermediate cooling of the compressor. Is promoted. (7) The water injection function can be easily added and the atomization of the spray can be achieved simply by simply modifying or replacing the diffuser, impeller and shaft using the structure of the centrifugal compressor. It is not necessary to collect the waste, and erosion and the like can be avoided. (8) In centrifugal compressors used for small gas turbines, etc., the places where water injection means can be arranged are limited,
The present invention does not require atomizing air piping for spray atomization, injection nozzles, etc., and the distance required for atomization,
Since no space is required, the method and apparatus are suitable for water injection into a centrifugal compressor.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing an example of a gas turbine using a centrifugal compressor.

FIG. 2 is a schematic configuration diagram illustrating an example of a centrifugal compressor.

FIG. 3 is a sectional configuration diagram of the centrifugal compressor shown in FIG.

FIG. 4 is an explanatory diagram showing a numerical analysis result of a gas flow velocity distribution of a centrifugal compressor and a diffuser.

FIG. 5 is a schematic configuration explanatory view showing a main part of a centrifugal compressor having a water injection function according to the first embodiment of the present invention.

FIG. 6 is a side view of the diffuser shown in FIG.

FIG. 7 is a schematic configuration explanatory view showing a main part of a centrifugal compressor having a water injection function according to a second embodiment of the present invention.

FIG. 8 is a schematic configuration diagram showing a main part of a centrifugal compressor having a water injection function according to a third embodiment of the present invention.

FIG. 9 is a schematic configuration explanatory view showing a main part of a centrifugal compressor having a water injection function according to a fourth embodiment of the present invention.

FIG. 10 is an enlarged perspective view of the bar-shaped member (perforated bar) shown in FIG.

FIG. 11 is a schematic cross-sectional explanatory view showing a main part of a centrifugal compressor having a water injection function according to a fifth embodiment of the present invention.

FIG. 12 is a schematic cross-sectional explanatory diagram illustrating a main part of a centrifugal compressor having a water injection function according to a sixth embodiment of the present invention.

FIG. 13 is a schematic cross-sectional explanatory view showing a main part of a centrifugal compressor having a water injection function according to a seventh embodiment of the present invention.

[Explanation of symbols]

10 Centrifugal compressor 12, 14 Impeller 16 Turbine 18 shaft 20 bearings 22 Diffuser 24 Return channel 26 Fuel nozzle 28 Combustor 30 Guide vane 32, 36, 40, 46, 48, 50 water injection holes 34 channel 38 flat plates 42 rod-shaped member 44 Injection water passage

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F04D 29/58

Claims (10)

(57) [Claims] 1. A rotatable shaft supported in a casing, an impeller rotating together with the shaft, the impeller constituting at least one compression stage disposed in the axial direction of the shaft, and fixed outside the impeller outlet. A method of injecting water for the purpose of intermediate cooling or the like into a centrifugal compressor having a diffuser installed as above, a gap between the casing and the impeller, and a gas flow path formed by the diffuser in the casing, wherein water is diffused by the diffuser. A water jet to a centrifugal compressor, characterized in that the water is jetted, and the jetted water collides with a plate-shaped member provided in a gas flow path on a diffuser to atomize the water. 2. A rotatable shaft supported in a casing, an impeller rotating together with the shaft, the impeller constituting at least one compression stage disposed in the axial direction of the shaft, and fixed outside the impeller outlet. In a method of injecting water for the purpose of intake air cooling or the like into a centrifugal compressor having a diffuser installed as a gasket formed by a diffuser in a casing and a gap between the casing and the impeller, the impeller inlet side A method of injecting water into a centrifugal compressor, characterized by injecting water from a shaft of (1) and using the increase in relative speed due to rotation to speed up and atomize the injected water . 3. A rotatable shaft supported in a casing, and an impeller rotating with the shaft, the impeller constituting a plurality of compression stages disposed in the axial direction of the shaft.
Water is injected into a multi-stage centrifugal compressor having a diffuser fixedly installed outside the impeller outlet, a gap between the casing and the impeller, and a gas flow path formed by the diffuser in the casing for the purpose of intermediate cooling and the like. A method for injecting water into a centrifugal compressor, comprising injecting water from a shaft on the inlet side of an impeller of a high-pressure stage and speeding up and atomizing the injected water by utilizing an increase in relative speed due to rotation . 4. A rotatable shaft supported in a casing, an impeller rotating with the shaft, the impeller constituting at least one compression stage disposed in the axial direction of the shaft, and fixed to an outer side of the impeller outlet. In a centrifugal compressor provided with a diffuser having guide vanes installed as described above, and a gap between the casing and the impeller and a gas flow passage formed by the diffuser in the casing, the gas in the flow passage between the diffuser vanes is provided. A centrifugal compressor having a water injection function, wherein a water injection hole is provided on a side having a high flow velocity, and water is injected from the water injection hole to atomize the injected water with the energy of airflow. 5. A rotatable shaft supported in a casing, an impeller that rotates with the shaft and constitutes at least one compression stage disposed in the axial direction of the shaft, and fixed to an outer side of the impeller outlet. In a centrifugal compressor provided with a diffuser having guide vanes installed as described above, a gap between a casing and an impeller, and a gas flow path formed by the diffuser in the casing, a water injection hole is provided on a side surface of a vane of the diffuser. At the same time, a plate-shaped member that also serves as a flow straightening plate and a guide plate is provided at a water injection position between the blades on the diffuser, and water is injected from the water injection holes to collide with the plate-shaped member so as to atomize the injected water. A centrifugal compressor having a water injection function. 6. A rotatable shaft supported in a casing, an impeller that rotates with the shaft and constitutes at least one compression stage disposed in the axial direction of the shaft, and fixed to an outer side of the impeller outlet. In a centrifugal compressor having a diffuser having guide vanes installed as a gap between the casing and the impeller and a gas passage formed by the diffuser in the casing, on a flow passage between the diffuser blades, A centrifugal compressor having a water injection function, wherein a rod-shaped member having a water injection hole is erected on a side surface, and water is injected from the water injection hole to atomize the injected water with the energy of airflow. 7. The centrifugal compressor having a water injection function according to claim 6 , wherein a rod-shaped member having a water injection hole on a side surface is rotatable, and the direction of injection can be arbitrarily set with respect to a gas flow. 8. The centrifugal compressor having a water injection function according to claim 6 , wherein a rod-shaped member having a water injection hole on a side face is fixedly installed so that water can be injected to a side having a high gas flow rate. 9. A rotatable shaft supported in a casing, an impeller that rotates with the shaft and constitutes at least one compression stage disposed in the axial direction of the shaft, and fixed to an outer side of the impeller outlet. In a centrifugal compressor including a diffuser having guide vanes installed as described above, a gap between a casing and an impeller, and a gas flow path formed by the diffuser in the casing, a jet water passage is provided in a shaft, and an impeller inlet is provided. At least one water injection hole that injects water that has passed through the injection water passage is provided on the side surface of the shaft, and water is injected from the water injection hole to the impeller inlet to increase the speed of the injection water by using the increase in relative speed due to rotation. A centrifugal compressor having a water injection function characterized by being atomized and atomized . 10. A rotatable shaft supported in a casing, an impeller that rotates with the shaft and constitutes a plurality of compression stages disposed in the axial direction of the shaft, and fixed to the outside of the impeller outlet. In a multi-stage centrifugal compressor including a diffuser having installed guide vanes, a gap between a casing and an impeller, and a gas flow path formed by a diffuser in the casing, a jet water passage is provided in a shaft, and a high-pressure stage is provided. At least one for injecting water that has passed through the injection water passage to the side of the shaft on the impeller inlet side
The water injection function is characterized by providing two water injection holes, spraying water from the water injection holes to the high pressure stage inlet, and using the increase in relative speed due to rotation to speed up and atomize the spray water Having a centrifugal compressor.