JPH09317696A - Stator blade structure of axial flow compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce mixing loss by arranging a channel inclined toward the direction of a stator blade shaft on the hub side of a stator blade inlet. SOLUTION: An inner ring shroud 5 is circumferentially attached at the end of the hub side of a stator blade 2, and a fin 6 is arranged in the circumferential direction of the end. The fin 6 is normally arranged axially, and a leaking amount is reduced in front and rear of the stator blade 2. A throttling channel 8 by which the blowout a leakage flow F3 to the flow F1 of a main flow of is controlled and which is inclined in the axial direction of the stator blade 2, is formed on the hub side of the stator blade 2 between an inner ring shroud 6 and a rotor blade implanting part 7. A guide vane 9 is arranged on the inlet hub side of the stator blade 2 of the throttling channel 8 so that the blowout flow direction of the leakage flow F3 to the flow F1 of the main flow is matched to the best inflow angle of the stator blade 2. Hereby, the turbulence of the main flow can be reduced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an axial flow compressor,
In particular, the present invention relates to a stator vane structure of an axial flow compressor that reduces the clearance loss of the vane.

[0002]

2. Description of the Related Art Needless to say, in order to improve the performance of a gas turbine plant, a combined cycle power plant, etc., it is important to improve the performance of an axial flow compressor which is one of its components. Yes.

Conventionally, various measures have been taken to improve the performance of an axial flow compressor. In particular, it is a well known fact that the leakage loss due to the gap between the tips of the moving blade and the stationary blade accounts for a large proportion of the loss of the axial compressor. In order to reduce this loss, various measures have been conventionally taken.

FIG. 5 is a sectional view showing a flow path portion of a conventional axial flow compressor. As shown in FIG. 5, the axial compressor includes a moving blade 1
And the stationary vane 2, the moving vane 1 is provided on the disk 3 attached to the rotating part, while the stationary vane 2 is attached to the casing 4 forming the flow path. Then, the rotational energy of the disk 3 is transmitted through the moving blades 1 to increase the pressure of the fluid flowing in from the inflow direction X. At this time, a pressure difference is generated before and after the moving blade 1 and the stationary blade 2, so that the fluid leaks from the gap at the tip of the blade and becomes a loss.

In order to reduce this so-called clearance loss, particularly the amount of leakage at the stationary blade 2, an inner ring shroud 5 is conventionally attached to the hub-side tip of the stationary blade 2 in the circumferential direction, and the tip circumferential direction of the inner ring shroud 5 is further arranged. The fin 6 is provided in the structure. A plurality of fins 6 are usually installed in the axial direction and have a function of reducing the amount of leakage before and after the stationary blade 2.

[0006]

As described above, in the conventional technique, the amount of leakage is reduced by the action of the fins 6 provided at the tip of the inner ring shroud 5.

However, it is impossible to reduce the gap between the fin 6 and the disk 3 which is the rotating portion to zero, and because of the pressure difference and the pumping effect of the disk 3 before and after the stationary blade 2, FIG. As shown in (4), the main flow F1 is sucked from the outlet opening of the vane 2, passes through the gaps at the tips of the fins 6 and is jetted into the main flow F1 toward the inlet of the vane 2 Is formed.

This circulation amount is due to the effect of the fins 6,
Although the amount of leakage is reduced to some extent, the flow is radially ejected at the inlet portion of the vane 2 and merges with the main flow F1. At this time, as shown in FIG. 6, the mainstream flow F1 flowing in the axial direction is disturbed, causing so-called mixing loss, which causes the loss.

Further, generally, the axial velocity distribution near the hub of the stationary blade 2 becomes an axial velocity distribution Y as shown in FIG. 7 due to the growth of the boundary layer, and the vicinity of the hub becomes a low energy region and the vicinity of the hub. It is known that the axial flow velocity of is slower than that of the main flow.

The state at this time is shown in FIG. 8 using the velocity triangle at the outlet of the moving blade 1. The velocity triangle in the mainstream is shown in a1. It can be seen that the flow exiting the moving blade 1 flows into the stationary blade 2 at an appropriate incident angle. The speed triangle on the hub side is a2
Since the hub side axial flow velocity is slower than the mainstream axial flow velocity as shown in FIG. 5, it can be understood that the inflow velocity vector b to the stationary blade 2 deviates from the proper incident angle.

Moreover, the velocity vector c in the blowing direction of the circulating flow to the main flow due to the leakage flow is dominated by the circumferential component induced by the rotation of the disk 3, and has almost no axial component. Further, since the direction thereof coincides with the rotating direction d of the moving blade 1, the deviation of the incident angle with respect to the stationary blade 2 is promoted.

On the other hand, FIG. 9 shows the relationship between the incident angle with respect to the stationary blade and the loss. The horizontal axis represents the deviation of the incident angle of the stationary blade 2 from the optimum point, and the vertical axis represents the loss coefficient. According to FIG. 9, it is understood that the loss coefficient sharply increases when the incident angle deviates from the proper value.

As described above, in the prior art, although the clearance loss due to the tip clearance of the stationary blade 2 can be reduced, the circulation flow due to the leakage flow F2 passing through the clearance between the fin 6 and the disk 3 becomes the main flow. By jetting in the radial direction, the main flow F1 is disturbed and new mixing loss occurs, and the circumferential velocity component of the jet flow may cause the incident angle to the rotor blade 1 to deviate from an appropriate value. There is a problem that it is promoted and the loss is increased.

The present invention has been made in consideration of the above-mentioned circumstances. By controlling the blowing velocity vector of the circulating flow generated by the leakage to the main flow, the mixing loss is reduced and the optimum point of the incident angle of the stationary blade is reduced. It is an object of the present invention to provide a stationary blade structure for an axial flow compressor that reduces the loss due to the deviation from.

[0015]

In order to solve the above-mentioned problems, according to claim 1 of the present invention, an inner ring shroud is attached to a hub-side tip of a stationary blade, and the inner ring shroud is provided with the inner ring shroud in the circumferential direction. In a vane structure of an axial compressor in which fins are installed to reduce the amount of fluid leakage flow from the outlet of the vane to the inlet, a flow passage inclined in the axial direction of the vane is provided on the hub side of the vane inlet. It is characterized by being provided.

According to a second aspect of the present invention, in the stator vane structure of the axial compressor according to the first aspect, the passage provided on the hub side of the inlet of the vane is formed as a throttle passage. .

According to a third aspect of the present invention, in the stator vane structure of the axial flow compressor according to the first or second aspect, the leakage flow of the fluid is caused on the inner ring shroud side of the throttle passage provided on the hub side of the stator vane inlet. It is characterized in that a guide vane was installed to control the blowing direction.

According to a fourth aspect of the present invention, in the stator vane structure for an axial flow compressor according to the first or second aspect, a leakage flow of the fluid is generated on the inner ring shroud side of the throttle passage provided on the hub side of the stator vane inlet. A guide plate for controlling the blowing direction is installed.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a first embodiment of a stationary blade structure of an axial compressor according to the present invention. Parts that are the same as or correspond to those of the conventional configuration will be described using the same reference numerals as in FIG. As shown in FIG. 1, the axial flow compressor of the present embodiment has a moving blade 1 and a stationary blade 2, and the moving blade 1 is provided on a disk 3 attached to a rotating portion, while the stationary blade 2 is a flow passage. Is attached to the casing 4 forming the.

An inner ring shroud 5 is circumferentially attached to the tip of the stationary blade 2 on the hub side, and fins 6 are provided in the circumferential direction of the tip of the inner ring shroud 5. A plurality of fins 6 are usually installed in the axial direction and have a function of reducing the amount of leakage before and after the stationary blade 2.

Further, in this embodiment, between the inner ring shroud 6 and the moving blade implanting portion 7 on the hub side of the stationary blade 2,
In order to control the blowing of the leak flow F3 to the main flow F1, the throttle flow passage 8 that is inclined in the axial direction of the stationary blade 2 is formed. On the inlet 2 hub side of the vane 2 in the throttle channel 8, the guide vanes 9 are arranged so that the flow direction of the leakage flow F3 to the main flow F1 is adjusted to the optimal inflow angle of the vane 2.
Is installed. The guide vane 9 is formed in a blade shape as shown in FIG. 2 and can control the blowing direction of the leakage flow F3.

Next, the operation of the present embodiment will be described.

Since the pressure at the outlet of the vane 2 is higher than the pressure at the inlet, part of the main flow passing through the vane 2 is sucked in at the outlet of the vane 2 and the inner ring shroud 5 of the vane 2 and the disk 3 are absorbed. Through the gap between the fin 6 and the disk 3,
It circulates to the inlet side of the vane 2 and forms a circulating flow of the leakage flow F3. As described above, when the leak flow F3 blows out into the main flow at the inlet side of the stationary blade 2, various losses occur.

According to this embodiment, since the throttle flow passage 8 is provided at the inlet side of the vane 2, that is, at the portion where the leakage flow F3 blows out to the main flow, the blowing direction of the leakage flow F3 is controlled in the axial direction. As shown in 1, the turbulence of the mainstream flow F1 is reduced.

The leak flow F3 passing through the throttle channel 8 is accelerated here. Furthermore, the blowing direction of the leakage flow F3 is controlled to the optimum incident angle of the stationary blade 2 by the guide vanes 9 installed in the throttle channel 8.

These actions will be described with reference to the velocity triangle shown in FIG. A speed triangle according to the related art is shown in A, and a speed triangle due to the throttle channel 8 is shown in B. The flow passing through the throttle channel 8 is accelerated in the axial direction of the stationary blade 2, and activates the low energy region of the boundary layer, thereby increasing the axial velocity of the main flow near the hub. As a result, the velocity triangle of the main flow in the vicinity of the hub is improved as shown in FIG. 3, and the inflow velocity vector of the stationary blade 2 is changed from C1 to C2, and the deviation from the optimum incident angle is corrected as compared with the conventional case.

Further, due to the action of the guide vanes 9 installed in the throttle channel 8, the blowout velocity vector of the leakage flow F3 becomes the velocity vector C4 having the stationary blade inflow design angle and blows out to the mainstream. Here, the inflow velocity vector into the vane 2 becomes C3 by combining with the above-described mainstream vane inflow velocity vector C2, and the deviation from the optimum incident angle is further corrected.

As described above, according to this embodiment, an axial velocity component is applied to the leakage flow F3 on the hub side of the inlet of the stationary blade 2,
Since the flow path is inclined to the axial direction of the stationary blade 2 in order to join the main flow F1, it is possible to reduce the turbulence of the main flow F1 caused by the leakage flow F3 blowing out into the main flow.

Since the flow passage provided on the inlet hub side of the stationary blade 2 is the throttle flow passage 8, the leak flow F3 has an axial velocity component and is further accelerated to become the main flow F1. By activating the low-energy region of the boundary layer for merging, the axial flow velocity near the hub rises, and the incident angle of the stationary blade 2 near the hub can be brought close to an appropriate value, reducing loss. be able to.

Further, a guide vane 9 is provided on the inner ring shroud 5 side of the throttle channel 8 provided on the inlet vane 2 inlet hub side to control the blowing velocity vector of the leakage flow F3 to the main flow, and the vane 2 thereof. By approaching the optimum incident angle, the incident angle of the stationary blade 2 near the hub can be further approximated to an appropriate value, and the loss can be reduced.

FIG. 4 is a perspective view showing a second embodiment of the stationary blade structure of the axial compressor according to the present invention. The same parts as those in the first embodiment will be described with the same reference numerals.

In the first embodiment, the blowout control of the leakage flow F3 is performed by the guide vane 9 having the airfoil cross section. However, in the present embodiment, the guide vane 9 is replaced by a plate as shown in FIG. The guide plate 10 in the shape of a circle is used. Therefore, even if the plate-shaped guide plate 10 is used as in the present embodiment, the same effect as in the first embodiment can be obtained.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made. For example, instead of the guide vane 9 of the first embodiment, a groove or the like for controlling the blowing direction may be formed, and as a matter of course, these control mechanisms are not used for rotating the inner ring shroud 5 which is a stationary system but for rotating. It may be provided on the side of the disc 3 which is a part.

[0035]

As described above, according to the first aspect of the present invention.
According to the authors, by providing a flow channel that is inclined in the axial direction of the stationary blade on the hub side of the inlet of the stationary blade, an axial velocity component is given to the leakage flow, and the leakage flow is merged along the direction of the main flow. It is possible to reduce the turbulence of the mainstream caused by blowing out in the mainstream in the direction.

According to a second aspect of the present invention, in the stator vane structure of the axial compressor according to the first aspect, since the flow passage provided on the hub side of the stator vane inlet is formed in the throttle flow passage, the leakage flow is reduced. Has an axial velocity component and is further accelerated to join the main flow, activating the low energy region of the boundary layer and increasing the axial flow velocity near the hub. As a result, the incident angle of the vane near the hub can be brought close to an appropriate value,
The loss can be reduced.

According to a third aspect of the present invention, in the stator vane structure of the axial flow compressor according to the first or second aspect, the leakage flow of the fluid flows to the inner ring shroud side of the throttle passage provided on the hub side of the stator vane inlet. By installing guide vanes that control the blowout direction of the stator, the blowout direction of the leak flow can be made closer to the optimum incident angle of the stationary blade, and the incident angle of the stationary blade near the hub can be made even closer to an appropriate value, and loss can be significantly reduced. Can be made.

According to a fourth aspect of the present invention, in the stator vane structure of the axial compressor according to the first or second aspect, the leakage flow of the fluid to the inner ring shroud side of the throttle passage provided on the hub side of the stator vane inlet. Since the guide plate for controlling the blowing direction of is installed, the same effect as the third aspect can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a stationary blade structure of an axial flow compressor according to the present invention.

FIG. 2 is an enlarged perspective view showing the guide vane of FIG.

FIG. 3 is an explanatory diagram showing an operation of the first embodiment of the present invention.

FIG. 4 is an enlarged perspective view showing a second embodiment of the stationary blade structure of the axial compressor according to the present invention.

FIG. 5 is a sectional view showing a flow path portion of a conventional axial flow compressor.

FIG. 6 is a cross-sectional view showing a stationary blade structure of a conventional axial flow compressor.

FIG. 7 is a cross-sectional view showing an axial velocity distribution in a stationary blade structure of a conventional axial flow compressor.

FIG. 8 is an explanatory view showing the action of a stationary blade structure of a conventional axial flow compressor.

FIG. 9 is a diagram showing a relationship between a deviation from a vane blade incident angle optimum point and a loss coefficient.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 moving blade 2 stationary blade 3 disk 4 casing 5 inner ring shroud 6 fins 7 blade inserting portion 8 throttle channel 9 guide vane 10 guide plate

Claims (4)

[Claims] 1. An inner ring shroud is attached to a hub-side tip of a vane, and fins are installed in a circumferential direction of a tip of the inner ring shroud to reduce a leak flow amount of fluid flowing from an outlet of the vane to an inlet. In the stator vane structure of the axial flow compressor, a stator vane structure of the axial flow compressor is characterized in that a flow passage inclined in the stator vane axial direction is provided on the hub side of the stator vane inlet. 2. The axial flow compressor according to claim 1, wherein the flow passage provided on the hub side of the stator vane inlet is a throttle flow passage. Vane structure of the machine. 3. The stationary vane structure for an axial flow compressor according to claim 1, wherein a blowing direction of a fluid leakage flow is set to an inner ring shroud side of a throttle passage provided on the hub side of the stationary vane inlet. A stator vane structure for an axial compressor, which is equipped with a control guide vane. 4. The static vane structure for an axial flow compressor according to claim 1, wherein a blowing direction of a fluid leakage flow is set to an inner ring shroud side of a throttle channel provided on the hub side of the stator vane inlet. A stator blade structure for an axial flow compressor, characterized in that a control guide plate is installed.