JPH0886300A - Prerevolution device for compressor - Google Patents

Abstract

PURPOSE: To prevent the generation of noise owing to a Karman vortex by a method wherein an intake air flow flowing through a moving vane is collected to the impeller side and development of turbulence at an intake air flow flowing through the moving vane is suppressed by protruding a flow straightening sheet to point the flow of intake air from the vane surface of a specified moving vane toward the impeller side. CONSTITUTION: A lever 6 serving as a mechanism to rotate moving vanes 4 in synchronism with each other is coupled to the rotary shaft 5 of each moving vanes 4 and the tip part of the lever 6 is coupled to a link 9 through a pin 8. By rotationally driving the rotary shaft 5 by means of an actuator, the moving vanes 4 are synchronously rotated through the ring 9. Further, a flow straightening sheet 7 to point a flow of intake air from the vane surface 12 on the suction side of a specified moving vane 4 toward an impeller 2 is protruded. The sheet-form flow straightening sheet 7 is protruded at right angles with the vane surface 12 of the moving vane 4. This constitution collects a flow of intake air flowing through the moving vanes 4 toward the impeller 2 and prevents the occurrence of turbulence of the intake air flow to prevent the generation of noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a pre-swirl device for a compressor.

[0002]

2. Description of the Related Art A gas turbine engine used as a prime mover of an automobile or the like has a wide operating range, and there is a demand for increasing the idle speed as much as possible in order to secure a starting acceleration from an idle state. As a countermeasure against this, a movable vane that pre-turns in the rotational direction of the impeller with respect to the intake air that flows into the impeller of the compressor is provided, while keeping the driving horsepower of the compressor low, keeping the idle rotational speed high and reducing fuel consumption. It is known that both improvement and acceleration can be achieved at the same time (reference material: “NASA CR-18
0891 ").

As a pre-swirl device for a compressor provided in a conventional gas turbine engine, as shown in FIGS. 17 and 18, for example, a plurality of movable vanes (in a flow passageway) introduced in an impeller 32 of an impeller 32 of a compressor 31 ( There is one in which the stationary vanes) 34 are annularly arranged.

The angle of each movable vane 34 is adjusted according to the operating condition, and when idle, each movable vane 34 is tilted as shown by the chain double-dashed line in FIG. A pre-turn is given to the rotation direction of the vehicle 32.

However, each movable vane 34 is shown in FIG.
In a driving state in which the movable vanes 34 are greatly tilted as indicated by a dotted line, abnormal noise having a frequency of 700 to 1150 Hz may be generated from each movable vane 34.

As shown in FIG. 19, the operating range in which abnormal noise is generated from the movable vanes 34 is an operating range in which the set angle of each movable vane 34 is a certain angle or more at a flow rate above a certain level. It is considered that the abnormal sound generated from the movable vanes 34 is phase-controlled under the condition that there is a Karman vortex generated from the rear end of each movable vane 34 in a disordered phase, and an acoustic standing wave exists.

As a countermeasure against this, the applicant of the present invention has filed Japanese Patent Application No.
A device already proposed as No. 124240 will be described.

As shown in FIG. 20, a specific movable vane 3
A flat plate-shaped tab (baffle plate) 35 is provided on the downstream side of 4.

By providing the tabs 35, it is possible to prevent the Karman vortices generated from the movable vanes 34 from being disturbed and prevent the Karman vortices from phase-integrating into an acoustic standing wave and generating abnormal noise. There is.

[0010]

However, in such a conventional structure, the tab 35 arranged on the downstream side of the movable vane 34 weakens the pre-turning force exerted by the movable vane 34 on the intake air.

As can be seen from the experimental results shown in FIG. 11 which will be described later, in the case of the conventional device having the tab 35 on the downstream side of the movable vane 34, the swirl imparted to the intake flow as the annular passage height increases. The flow angle tends to be small.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a variable guide vane that prevents the generation of abnormal noise without weakening the pre-turning force applied to the intake air by the movable vanes.

[0013]

According to the first aspect of the present invention,
In a pre-swirl device for a compressor, which is provided with a plurality of movable vanes arranged side by side in an annular shape in an inlet passage for introducing intake air into the impeller of the compressor, and which has a mechanism for rotating each movable vane,
A straightening vane that directs the flow of intake air toward the impeller is projected from the blade surface of a specific movable vane.

According to a second aspect of the present invention, the compressor is provided with a plurality of movable vanes arranged in a line in an inlet passage for introducing intake air into the impeller of the compressor, and a mechanism for rotating each movable vane. In the pre-swivel system of the machine, a straightening vane that projects from the suction side blade surface of a specific movable vane and directs the flow of intake air toward the impeller is provided, and the straightening vane is inclined with respect to the center line of the inlet passage. To form a guide surface.

According to a third aspect of the present invention, the compressor is provided with a plurality of movable vanes arranged in a line in an inlet passage for introducing intake air into the impeller of the compressor, and a mechanism for rotating each movable vane. In the pre-swivel system of the machine, a straightening vane that projects from the suction side blade surface of a specific movable vane and directs the flow of intake air toward the impeller is provided, and the straightening vane is inclined with respect to the center line of the inlet passage. Forming a guide surface for contacting the upstream end of the straightening vane with the wall surface of the inner shroud defining the inlet passage.

The invention according to claim 4 is provided with a plurality of movable vanes arranged in an annular manner in an inlet passage for introducing intake air into an impeller of a compressor, and a compression provided with a mechanism for rotating each movable vane. In the pre-swivel system of the machine, a straightening vane that projects from the suction side blade surface of a specific movable vane and directs the flow of intake air toward the impeller is provided, and the straightening vane is inclined with respect to the center line of the inlet passage. To form a guide surface for contacting the upstream end of the straightening vane with the wall surface of the inner shroud defining the inlet passage, and the distance l between the downstream end of the straightening vane and the inner shroud defining the inlet passage. Is set to a value of 60% or more with respect to the channel width L of the inlet channel.

According to a fifth aspect of the present invention, the compressor is provided with a plurality of movable vanes arranged in a line in an inlet passage for introducing intake air into the impeller of the compressor, and a mechanism for rotating each movable vane. In the pre-swivel system of the machine, a straightening vane that projects from the suction-side blade surface of a specific movable vane and directs the flow of intake air toward the impeller is used. With respect to the minimum arc connecting the downstream ends of the vanes, the protrusion amount T at which the downstream end of the rectifying plate protrudes to the downstream side of the minimum arc is defined by the radius R of the minimum arc.
Set to a value of 1.7% or more of _D.

According to a sixth aspect of the present invention, the compressor is provided with a plurality of movable vanes arranged in a line in an inlet passage for introducing intake air into the impeller of the compressor, and a mechanism for rotating each movable vane. In the pre-swivel system of a machine, a straightening vane that directs the flow of intake air toward the impeller is projected from the blade surface of a specific movable vane, is orthogonal to the intake direction of the intake air to the inlet passage, and rotates the impeller. A straightening vane is attached to the movable vane arranged near the line segment that intersects the center line.

According to a seventh aspect of the present invention, a compressor is provided with a plurality of movable vanes arranged in a line in an inlet passage for introducing intake air into the impeller of the compressor, and a mechanism for rotating each movable vane. In the pre-swirling device of No. 2, the flow straightening plate that projects from the blade surface of a specific movable vane and directs the flow of intake air toward the impeller is formed by a member having a wedge-shaped cross-section, and the inlet flow to the flow straightening plate is A guide surface is formed which is inclined with respect to the center line of the passage.

[0020]

According to the first aspect of the present invention, since the rectifying plate that directs the flow of the intake air toward the impeller is projected from the blade surface of the specific movable vane, the specific movable vane that may generate the Karman vortex is provided. The attached rectifying plate collects the intake flow passing through the movable vane toward the impeller and suppresses the development of turbulence in the intake flow passing through the movable vane. Prevents noise from being generated as waves.

Since the flow straightening plate projects from the blade surface of the movable vane and is arranged in the flow path between the movable vanes, it is possible to prevent the movable vane from weakening the pre-turning force applied to the intake air.

According to the second aspect of the present invention, since the flow guide plate protruding from the suction side blade surface of the specific movable vane is formed with the guide surface inclined with respect to the center line of the inlet flow passage,
The guide surface collects the intake air flow passing through the flow straightening plate toward the impeller, and suppresses the development of turbulence in the intake air flow passing through the movable vanes, and the Karman vortices are phase-integrated into an acoustic standing wave. Prevent the generation of abnormal noise.

According to a third aspect of the present invention, there is provided an inner shroud in which a guide surface that is inclined with respect to the flow path center line of the inlet flow path is formed on the flow straightening plate and the upstream end of the flow straightening plate defines the inlet flow path. Since it is in contact with the wall surface, after separating the intake air flow passing through the flow straightening plate from the wall surface of the inner shroud, it is collected by the guide surface toward the impeller to suppress the development of turbulence in the intake air flow passing through the movable vanes. Thus, the Karman vortices are phase-integrated to form an acoustic standing wave and prevent abnormal noise.

According to a fourth aspect of the present invention, there is provided an inner shroud in which a guide surface that is inclined with respect to the flow path center line of the inlet flow path is formed on the flow straightening plate and the upstream end portion of the flow straightening plate defines the inlet flow path. The distance l between the downstream end of the straightening vane and the inner shroud that defines the inlet flow passage is set to a value of 60% or more with respect to the flow passage width L of the inlet flow passage. After separating the intake air flow passing through the inner shroud from the wall surface of the inner shroud, the guide surface can efficiently collect it toward the impeller, suppressing the development of turbulence in the intake air flow passing through the movable vane, The vortices are prevented from phase-integrating into an acoustic standing wave to generate abnormal noise.

According to a fifth aspect of the present invention, there is provided a straightening vane which projects from the blade surface on the suction side of a specific movable vane and directs the flow of intake air toward the impeller, and the minimum movable vane setting angle at which abnormal noise is generated. At the minimum arc connecting the downstream ends of the movable vanes, the protrusion amount T at which the downstream end of the straightening vane projects to the downstream side of the minimum arc is defined by the radius R of the minimum arc.
_Since it is set to a value of 1.7% or more of _D , it is possible to efficiently collect the intake flow passing through the straightening vane toward the impeller while suppressing the weakening of the pre-turning force given to the intake by the movable vanes. , It suppresses the development of turbulence in the intake air flow passing through the movable vanes, and prevents the Karman vortices from phase-integrating into an acoustic standing wave and generating abnormal noise.

According to a sixth aspect of the present invention, a rectifying plate that directs the flow of the intake air toward the impeller is projected from the blade surface of the specific movable vane, and is orthogonal to the suction direction of the intake air with respect to the inlet passage, and Since the rectifying plate was attached to the movable vane located near the line segment that intersects with the rotation center line of the impeller, the rectifying plate will be attached to the movable vane that may generate Karman vortices. It effectively prevents the Karman vortices from phase-integrating into an acoustic standing wave and generating abnormal noise.

According to the seventh aspect of the present invention, since the straightening vane is composed of a member having a wedge-shaped cross section, and the straightening vane is formed with the guide surface inclined with respect to the center line of the inlet passage, the movable vane is The Karman vortex is suppressed by suppressing the weakening of the pre-turning force applied to the intake air, collecting the intake air flow passing through the flow straightening plate toward the impeller, and suppressing the development of turbulence in the intake air flow passing through the movable vanes. Prevents the abnormal noise from being generated by integrating the phases into an acoustic standing wave.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment in which the present invention is applied to a compressor of a gas turbine engine will be described below with reference to the accompanying drawings.

As shown in FIG. 2, an impeller 2 of the compressor 1 and a compressor driving turbine 15 are connected to the rotary shaft 11. The intake air compressed by the compressor 1 is sent to the combustor, the fuel is burned in the combustor, and the turbine 15 and an output turbine (not shown) are rotationally driven by the combustion gas discharged from the combustor.

The inlet passage 3 for guiding intake air to the impeller 2 is defined between the inner shroud 21 and the outer shroud 22. When the impeller 2 rotates, the intake air flowing from the inlet flow path 3 is sucked into the flow path between the blades 14 and is compressed by centrifugal force while changing its direction in the radial direction.
The relative speed is reduced through the diffuser 13 spreading from the outer peripheral end of the impeller 2, whereby the pressure is recovered.

As a pre-swirl device of the compressor 1, as shown in FIG. 1, a plurality of fixed vanes 16 and movable vanes 4 are annularly arranged side by side at a predetermined equal interval in the inlet passage 3 of the compressor 1. Set up. The fixed vanes 16 are arranged radially with respect to the rotation center line of the impeller 2. Each movable vane 4 extends from the rear end of the fixed vane 16 to the downstream side, and is bent with respect to the fixed vane 16 according to the operating conditions, so that each fixed vane 1
A pre-turn is given to the intake air passing through 6 and the movable vane 4. The fixed vanes 16 may be omitted.

A lever 6 is connected to the rotary shaft 5 of each movable vane 4 as a mechanism for synchronously rotating each movable vane 4, and the tip of each lever 6 is connected to a ring 9 via a pin 8. By rotating one rotating shaft 5 by an actuator (not shown), the movable vanes 4 are rotated in synchronization via the ring 9.

As shown in FIGS. 3, 4, 5 and 6, respectively, the blade surface 1 on the suction side of the specific movable vane 4 is shown.
A straightening vane 7 that directs the flow of intake air from 2 toward the impeller 2 is projected. The thin plate current plate 7 is the blade surface 1 of the movable vane 4.
It projects orthogonally to 2.

The straightening vanes 7 are inserted into the grooves formed in the movable vanes 4 at their ends, for example, and are fixed by welding.
It is also conceivable to press fit the rectifying plate 7 into the movable vane 4 or to fix it with an adhesive.

The suction direction of the intake air to the inlet passage 3 is
As shown by the outline arrows in FIG. 1, they are arranged in two directions that are opposed to each other on a straight line. One straightening vane 7 is attached to the movable vane 4 which is orthogonal to each suction direction and arranged on a line segment that intersects with the rotation center line of the impeller 2.

Two straightening vanes 7 are respectively attached to two movable vanes 4 which are arranged in the vicinity of a line segment which is orthogonal to the respective suction directions and intersects with the rotation center line of the impeller 2. However, it is also possible to improve the sound deadening effect.

The thin plate current plate 7 has a guide surface 17 and a back surface 18.
Have. The guide surface 17 of the straightening vane 7 is arranged so as to be inclined with respect to the center line of the inlet passage 3 so as to direct the flow of the intake air toward the impeller 2.

Based on the experimental results described later, the distance 1 between the downstream end 20 of the straightening vane 7 and the inner shroud 21 is
The distance between the inner shroud 21 and the outer shroud 22 is set to a value of 60% or more with respect to the flow passage width L of the inlet flow passage 3.

The rectifying plate 7 has a protruding width which is formed in a substantially constant band shape at a portion located laterally of the movable vane 4, and is formed in a trapezoidal shape which extends toward an upstream side at a portion located laterally of the fixed vane 16. To be done.

The straightening vane 7 is formed such that its upstream end portion 19 projects toward the upstream side of the fixed vane 16. The current plate 7 is curved and formed so that the guide surface 17 is recessed in the middle thereof. As shown in FIG. 7, the current plate 7 is attached so that the back surface 18 of the upstream end 19 of the current plate 7 is brought into sliding contact with the wall surface of the inner shroud 21.

As shown in FIG. 8, the straightening vane 7 has a straightening vane 7 with respect to a minimum arc connecting the downstream end portions 23 when the movable vane 4 is at the minimum movable vane setting angle at which abnormal noise is generated. The amount T of protrusion of the downstream end portion 20 of the above-mentioned protrusion to the downstream side of the minimum arc is set to a value of 1.7% or more of the radius R _D of the minimum arc.

Next, the operation will be described.

As shown by the white arrow in FIG. 1, the intake air that has flowed into the inlet flow path 3 from two suction directions that are linearly opposed to each other passes through the fixed vanes 16 and the movable vanes 4 and is operated. Pre-swirl is given to the intake air flowing into the impeller 2 according to the set angle of the movable vane 4 that bends with respect to the fixed vane 16 according to the conditions. At this time, the intake air passing through the movable vanes 4 arranged on the line segment orthogonal to each suction direction and intersecting the rotation center line of the impeller 2 joins the intake air guided from the two suction directions. Without the flow straightening plate 7, the turbulence of the intake air flow may develop to generate Karman vortices, which may cause abnormal noise of 700 to 1150 Hz.

The straightening vanes 7 attached to the movable vanes 4 which may generate Karman vortices thus collect the intake flow passing through the movable vanes 4 toward the impeller 2 along the outer shroud 22. It suppresses the development of turbulence in the intake air flow passing through the movable vanes 4,
Hz It prevents the generation of abnormal noise.

FIG. 9 shows that the ratio 1 / L × 100% of the distance 1 between the downstream end 20 of the straightening vane 7 and the inner shroud 21 to the distance L between the inner shroud 21 and the outer shroud 22 is 50%, The experimental results of measuring the set angle and the flow rate range of the movable vane 4 where the sound is generated when the ratio is changed to 60% and 70% are shown. However,
In this case, 2 are arranged in the vicinity of a line segment that is orthogonal to each suction direction of the intake air and that intersects with the rotation center line of the impeller 2.
Two movable vanes 4 are attached to each movable vane 4.

From this experimental result, 1 / L × 100% is 6
By setting the value to 0% or more, 1 / L x 100%
It can be seen that the same muffling effect can be obtained when the value is set to 70% or more.

FIG. 8 shows the ratio T / R _D × 100% of the protrusion amount T of the downstream end 20 of the straightening vane 7 to the radius R _D of the minimum arc connecting the downstream ends 23 of the movable vanes 4 to 1 ．
The experimental results of measuring the set angle and the flow rate range of the movable vane 4 where the sound is generated when the values are changed to 0%, 1.7% and 2.0% are shown. However, in this case, two movable vanes 4 are arranged in the vicinity of a line segment that is orthogonal to each suction direction of the intake air and that intersects with the rotation center line of the impeller 2.
Each of the straightening vanes 7 is attached, and the distance l between the downstream end 20 of the straightening vane 7 and the inner shroud 21 is
The ratio 1 / L × 100% to the distance L between the inner shroud 21 and the outer shroud 22 is set to 60%.

The radius R _D used here is
This is the radius of the smallest arc connecting the downstream end portions 23 of the movable vane 4 at the set angle of the movable vane 4 where abnormal noise is generated. However, the set angle of the movable vane 4 in which abnormal noise is generated is not one, and in the conventional device, as shown in FIG. 19, it is distributed in a range of slightly less than 40 ° to 60 ° or more. Therefore, the radius R _{D is} also distributed according to the set angle of the movable vane 4.

From the result of this experiment, the ratio T of the protrusion amount T
It can be seen that by setting / R _D × 100% to a value of 1.7%, the same silencing effect as when T / R _D × 100% is set to a value of 2.0% or more can be obtained.

FIG. 10 shows a case where a gap is provided between the upstream end of the current plate and the wall surface of the inner shroud 21.
The experimental result which measured the setting angle of the movable vane 4 and the flow area which generate a sound is shown. From this experimental result, it is understood that the silencing effect can be enhanced by sliding the upstream end portion 19 of the straightening vane 7 in contact with the wall surface of the inner shroud 21.

In this way, the downstream end 20 of the straightening vane 7 is
By setting the protruding amount T of B to be small, it is possible to prevent the fixed vane 16 and the movable vane 4 from weakening the pre-turning force applied to the intake air. As a result, the fixed vane 16 and the movable vane 4 sufficiently increase the pre-turning force imparted to the intake air to suppress the driving horsepower of the compressor to a small value, while keeping the idle speed high, thereby improving fuel efficiency and acceleration. Can be made compatible.

FIG. 11 shows the inner shroud 2 in the annular passage located immediately upstream of the impeller 2 of the inlet passage 3.
Fixed vanes 16 from 1 to outer shroud 22
And experimental results of measuring the distribution of the swirling flow angle given to the intake air flow passing through the movable vane 4. However, the setting angle of the movable vane 4 is set to 60 °.

As can be seen from the results of this experiment, in the case of the conventional apparatus having the tab 35 on the downstream side of the movable vane 34 shown in FIG. 20, it is given to the intake flow as the height of the annular passage increases. The swirl flow angle tends to be small. On the other hand, in the case of the device according to the present invention, the swirling flow angle can be provided in the same manner as the standard pre-swirl device having no straightening vane or tab even if the height of the annular passage is increased.

Next, in another embodiment shown in FIGS. 12, 13 and 14, the current plate 24 is made of a member having a wedge-shaped cross section. It should be noted that the same reference numerals are used for parts corresponding to those in FIGS.

The straightening vane 24 is formed in a block shape having a guide surface 25 inclined with respect to the center line of the flow path of the inlet flow path 3. The current plate 24 is fixed to each movable vane 4 by welding, for example.

The rectifying plate 24 is attached so that its back surface 26 is brought into sliding contact with the wall surface of the inner shroud 21.

The suction direction of the intake air to the inlet passage 3 is
As shown by the white arrow in FIG.
Are arranged in the direction. Movable vanes 4 arranged with two straightening vanes 24 orthogonal to each suction direction and on or near a line segment that intersects with the rotation center line of the impeller 2.
Install each one.

In this case, the straightening vane 24 collects the intake flow passing through the movable vane 4 toward the impeller 2 along the outer shroud 22 and suppresses the development of turbulence in the intake flow passing through the movable vane 4. Thus, it is possible to prevent the generation of abnormal noise of 700 to 1150 Hz.

FIG. 16 shows the experimental results obtained by measuring the set angle and flow rate range of the movable vanes 4 in which sound is generated when the block-shaped flow straightening plate 24 is attached to each movable vane 4. From this experimental result, it can be seen that a sufficient silencing effect can be obtained.

[0060]

As described above, according to the first aspect of the present invention, the Karman vortex may be generated because the straightening vane for directing the flow of intake air toward the impeller is projected from the blade surface of the specific movable vane. A straightening vane attached to a specific movable vane collects the intake air flow passing through the movable vane toward the impeller, and suppresses the development of turbulence in the intake air flow passing through the movable vane, thereby causing a Karman vortex. It is possible to prevent the abnormal noise from being generated by the phase integration due to the acoustic standing wave, and to suppress the weakening of the pre-turning force that the movable vane gives to the intake air. It is possible to increase the power sufficiently and suppress the driving horsepower of the compressor to a small value, while keeping the idle speed high, thereby improving both fuel efficiency and acceleration.

According to the second aspect of the present invention, since the flow guide plate projecting from the suction side blade surface of the specific movable vane is formed with the guide surface inclined with respect to the center line of the inlet flow passage,
The guide surface collects the intake air flow passing through the flow straightening plate toward the impeller, and suppresses the development of turbulence in the intake air flow passing through the movable vanes, and the Karman vortices are phase-integrated into an acoustic standing wave. Prevent the generation of abnormal noise.

According to the third aspect of the present invention, a guide surface is formed on the straightening vane which is inclined with respect to the center line of the inlet flow passage, and the upstream end portion of the straightening vane defines the inlet flow passage. Since it is in contact with the wall surface, after separating the intake air flow passing through the flow straightening plate from the wall surface of the inner shroud, it is collected by the guide surface toward the impeller to suppress the development of turbulence in the intake air flow passing through the movable vanes. Thus, the Karman vortices are phase-integrated to form an acoustic standing wave and prevent abnormal noise.

According to the fourth aspect of the present invention, a guide surface is formed on the straightening vane that is inclined with respect to the center line of the inlet flow passage, and the upstream end of the straightening vane defines the inlet flow passage. The distance l between the downstream end of the straightening vane and the inner shroud that defines the inlet flow passage is set to a value of 60% or more with respect to the flow passage width L of the inlet flow passage. After separating the intake air flow passing through the inner shroud from the wall surface of the inner shroud, the guide surface can efficiently collect it toward the impeller, suppressing the development of turbulence in the intake air flow passing through the movable vane, The vortices are prevented from phase-integrating into an acoustic standing wave to generate abnormal noise.

According to a fifth aspect of the present invention, the minimum movable vane that causes abnormal noise is set by providing a straightening vane that projects from the suction-side blade surface of a specific movable vane and directs the flow of intake air toward the impeller. In terms of angle, with respect to the minimum arc connecting the downstream ends of the movable vanes, the protrusion amount T by which the downstream end of the rectifying plate projects downstream from the minimum arc is 1.7% or more of the radius R _D of the minimum arc. Since it is set to the value of, while suppressing the weakening of the pre-turning force that the movable vane gives to the intake air,
It is possible to efficiently collect the intake air flow that passes through the flow straightening plate toward the impeller, suppress the development of turbulence in the intake air flow that passes through the movable vanes, and integrate the Karman vortex with the acoustic standing wave. To prevent abnormal noise.

According to a sixth aspect of the present invention, a rectifying plate that directs the flow of intake air toward the impeller is projected from the blade surface of a specific movable vane, and is orthogonal to the intake direction of the intake air with respect to the inlet passage, and Since the rectifying plate was attached to the movable vane located near the line segment that intersects with the rotation center line of the impeller, the rectifying plate will be attached to the movable vane that may generate Karman vortices. It effectively prevents the Karman vortices from phase-integrating into an acoustic standing wave and generating abnormal noise.

According to the seventh aspect of the invention, since the straightening vane is formed of a member having a wedge-shaped cross-section and the straightening vane is formed with the guide surface inclined with respect to the center line of the inlet passage, the movable vane is The Karman vortex is suppressed by suppressing the weakening of the pre-turning force applied to the intake air, collecting the intake air flow passing through the flow straightening plate toward the impeller, and suppressing the development of turbulence in the intake air flow passing through the movable vanes. Prevents the abnormal noise from being generated by integrating the phases into an acoustic standing wave.

[Brief description of drawings]

FIG. 1 is a front view of a pre-turning device showing an embodiment of the present invention.

FIG. 2 is a sectional view of the compressor.

FIG. 3 is a front view of a current plate and movable vanes.

FIG. 4 is a side view of the current plate and each movable vane.

FIG. 5 is a plan view of the current plate and each movable vane as seen from the upstream side.

FIG. 6 is a perspective view of a current plate and movable vanes.

FIG. 7 is a sectional view of the pre-turning device.

FIG. 8 is a view showing the same experimental result.

FIG. 9 is a view showing the same experimental result.

FIG. 10 is a view showing experimental results similarly.

FIG. 11 is a view showing the same experimental result.

FIG. 12 is a front view of a current plate and movable vanes according to another embodiment.

FIG. 13 is a side view of the current plate and each movable vane.

FIG. 14 is a sectional view of the pre-turning device.

FIG. 15 is a front view of the pre-turning device.

FIG. 16 is a view showing the same experimental result.

FIG. 17 is a sectional view of a compressor showing a conventional example.

FIG. 18 is a sectional view taken along line AA of FIG.

FIG. 19 is a diagram showing a region where abnormal noise is generated in accordance with the set angle of the movable vanes and the flow rate.

FIG. 20 is a front view of a pre-turning device showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Impeller 3 Inlet flow path 4 Movable vane 7 Straightening plate 9 Ring 17 Guide surface 12 Blade surface 16 Fixed vane 19 Upstream end 20 Downstream end 21 Inner shroud 24 Movable vane 25 Guide surface

Claims (7)

[Claims] 1. A pre-swirl device for a compressor, comprising a plurality of movable vanes arranged in a line in an inlet passage for introducing intake air into an impeller of the compressor, and a mechanism for rotating the movable vanes. A pre-swirl device for a compressor, characterized in that a straightening vane that directs the flow of intake air toward the impeller is projected from the blade surface of a specific movable vane. 2. A pre-swirl device for a compressor, comprising a plurality of movable vanes arranged in a line in an inlet passage for introducing intake air into an impeller of the compressor, and a mechanism for rotating each movable vane. , Equipped with a straightening plate that projects from the blade surface on the suction side of a specific movable vane and directs the flow of intake air toward the impeller, and a guide surface that is inclined with respect to the center line of the inlet flow path is formed on the straightening plate. A pre-turning device for a compressor, which is characterized in that 3. A pre-swirl device for a compressor, comprising a plurality of movable vanes annularly arranged in an inlet passage for introducing intake air into an impeller of the compressor, and a mechanism for rotating each movable vane. , Equipped with a straightening vane that projects from the suction side blade surface of a specific movable vane and directs the flow of intake air toward the impeller, and forms a guide surface that is inclined with respect to the flow passage centerline of the inlet flow passage on the straightening vane. A pre-swirl device for a compressor, characterized in that the upstream end of the straightening vane is brought into contact with the wall surface of the inner shroud defining the inlet passage. 4. A pre-swirl device for a compressor, comprising a plurality of movable vanes arranged in an annular shape in an inlet passage for introducing intake air into an impeller of the compressor, and a mechanism for rotating each movable vane. , Equipped with a straightening vane that projects from the suction side blade surface of a specific movable vane and directs the flow of intake air toward the impeller, and forms a guide surface that is inclined with respect to the flow passage centerline of the inlet flow passage on the straightening vane. , The upstream end of the straightening vane is brought into contact with the wall surface of the inner shroud defining the inlet passage, and the distance l between the downstream end of the straightening vane and the inner shroud defining the inlet passage is set to 60 for flow path width L
A pre-swivel device for a compressor characterized by being set to a value of at least%. 5. A pre-swirl device for a compressor, comprising a plurality of movable vanes arranged in an annular manner in an inlet passage for introducing intake air into an impeller of the compressor, and a mechanism for rotating each movable vane. , Equipped with a straightening vane that projects from the suction-side blade surface of a specific movable vane and directs the flow of intake air toward the impeller, and sets the downstream end of each movable vane at the minimum movable vane setting angle at which abnormal noise is generated. With respect to the minimum arc to be connected, the amount of protrusion T of the downstream end of the straightening plate projecting to the downstream side of the minimum arc is set to a value of 1.7% or more of the radius R _D of the minimum arc. Pre-turning device for machine. 6. A pre-swirl device for a compressor, comprising a plurality of movable vanes arranged in a line in an inlet passage for introducing intake air into an impeller of the compressor, and a mechanism for rotating each movable vane. , A line segment that projects a straightening vane that directs the flow of intake air from the blade surface of a specific movable vane toward the impeller and that is orthogonal to the suction direction of the intake air to the inlet flow path and intersects the rotation center line of the impeller. A pre-swirl device for a compressor, characterized in that a current vane is attached to a movable vane disposed in the vicinity of the upper part. 7. A pre-swirl device for a compressor, comprising a plurality of movable vanes arranged in a line in an inlet passage for introducing intake air into an impeller of the compressor, and a mechanism for rotating each movable vane. , Equipped with a straightening vane that projects from the blade surface of a specific movable vane and directs the flow of intake air toward the impeller. The straightening vane is composed of a member with a wedge-shaped cross section, and the straightening vane is the center of the inlet flow passage. A pre-swirl device for a compressor, characterized in that a guide surface inclined with respect to the line is formed.