JPH0821398A - Rotor blade of compressor - Google Patents

Abstract

PURPOSE:To improve compressing efficiency by forming an inclined flow passage with its exit located more in a radial outside direction than its entrance between a casing and a rotationally-driven disk and disposing a reverse chamber part in a part of a rotor blade attached to the disk. CONSTITUTION:When a reverse chamber part 41 is disposed on a rotor blade 40, a part of compressed air flows along the projecting surface 42 or the recessed surface 43 of the reverse chamber part 41. When a part of compressed air meanders in the vicinity of the reverse chamber part 41, a centrifugal force fo and a static pressure difference DELTAp in a circumferentia direction are applied to the compressed air flow. A resultant force consisting of this centrifugal force fo and the static pressure difference DELTAp is provided with a component in a direction opposite to that of a divided force fc of a Coriori's force and thus thease offset each other. Therefore, by balancing the vector sum of the centrifugal force fo and the static pressure difference DELTAp with the devided pressure fc of the Corioli's force, an imbalanced component of these can be reduced in the vicinity of a hub 2 and a casing. Also generation of a secondary flow among rows of the rotor blades 40 can be limited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving blade of a compressor,
In particular, it is intended to improve the efficiency of the compressor by reducing the influence of Coriolis force.

[0002]

2. Description of the Related Art FIG. 3 shows an example of the structure of a mixed flow compressor. In the mixed flow compressor, a flow path 3 is formed between the casing 1 and a hub (disk) 2 that is rotationally driven, in an inclined state in which the outlet is radially outward with respect to the inlet.
The air is compressed by the moving blades 4 integrally attached to the
It is sent out to the rear of the flow path 3.

European Patent Application Publication No. 0201318, which has been proposed as a related technique for a gas turbine engine used in an aircraft, also describes a technique for applying a mixed flow compressor.

In these mixed-flow compressors, as shown in FIG. 3, the compressed air flow L between the moving blades 4 flows obliquely with respect to the axial direction, so that the Coriolis force is applied to the velocity component in the radial direction. Is known to work.

[0005]

However, the compressed air flow L
Is decelerated in the vicinity of the casing side and the hub side of the moving blade 4, so that a phenomenon occurs in which the flow velocity in the vicinity of the casing 1 and the hub 2 becomes slower than the flow velocity in the mainstream portion, which occupies most of the compression. Centrifugal force fo generated by the air flow L being curved as a whole and the component force f of the Coriolis force in that direction.
c becomes smaller near the casing 1 and the hub 2.
Therefore, when the moving blade 4 moves as shown by the arrow in FIG. 4, in the mainstream portion, the static pressure difference Δp between the pressure surface and the suction surface based on the curved shape of the moving blade 4, the centrifugal force fo, and the Coriolis force. However, in the vicinity of the casing 1 and the hub 2, a large unbalanced component is generated in the sum of the static pressure difference Δp and the centrifugal force fo and the component force fc of the Coriolis force.
A secondary flow as indicated by an arrow in FIG. 5 is generated based on the unbalanced component, which causes a reduction in compression efficiency.

The present invention has been made in view of these problems, and suppresses the generation of a secondary flow due to the component of static pressure difference, centrifugal force and Coriolis force in the vicinity of the casing and the hub, and improves the compression efficiency. Is intended.

[0007]

In a moving blade of a compressor according to the present invention, between a casing and a rotationally driven disk, a flow path in an inclined state in which an outlet is radially outward rather than an inlet In the compressor in which the blade is formed and the moving blade is attached to the disk, a configuration in which the reverse camber portion is arranged in a part of the moving blade is adopted. Further, a configuration in which the reverse camber portion is disposed at a position rearward from the vicinity of the center of the chord length of the moving blade and a configuration in which the reverse camber portion is formed by meandering the cross-sectional shape of the moving blade are added. In this case, the camber angle of the moving blade is set to be equal to that when the reverse camber portion is not attached.

[0008]

The air introduced into each moving blade is compressed not only by the camber of the moving blade but also by the centrifugal force due to the fact that the flow passage is guided radially outward,
When the flow path between the casing and the disk is guided radially outward, a Coriolis force acts on the radial velocity component of the compressed air flow. In this case, if the reverse camber portion is arranged in a part of the moving blade, centrifugal force is generated due to the meandering of the air flow in the vicinity of the reverse camber portion. The generation of the secondary flow is suppressed by canceling out the static pressure difference between the pressure surface and the suction surface of the blade. Further, in a moving blade having a structure that produces a velocity component in the radial direction, when the reverse camber portion is arranged at the rear position of the moving blade, the velocity component of the compressed air flow increases in this portion, which causes the above-mentioned cancellation. The generation of the secondary flow is suppressed to be large, and the performance of the compressor is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a moving blade of a compressor according to the present invention will be described below with reference to FIGS. 1, 2 and 3.

In the embodiment, between the casing 1 shown in FIG. 3 and the disk (hub) 2 which is rotationally driven, the flow passage is in an inclined state in which the outlet is radially outward rather than the inlet. 3, the moving blades 40 having different shapes and functions from those in FIG. 3 are attached to the disk 2.

That is, as shown in FIGS. 1 and 2, a part of the moving blade 40, that is, the reverse camber portion 4 in a state where the cross-sectional shape is meandered to a position rearward from the vicinity of the center of the chord length.
1 is allocated.

With such a rotor blade 40, the disk 2
Is rotated as shown by the white arrow in FIG. 1, the air introduced into each moving blade 40 is compressed by deceleration when passing between the moving blades 40, but as shown in FIG. Coriolis force is also generated due to the fact that 3 is guided radially outward.

As shown in FIG. 1, when the reverse camber portion 41 is arranged on the moving blade 40, a part of the compressed air flow L is a convex surface 42 or a concave surface 43 in the reverse camber portion 41.
Flowing along. When a part of the compressed air flow L meanders in the vicinity of the reverse camber portion 41, the centrifugal force fo and the circumferential static pressure difference Δp act on the compressed air flow L based on the meandering. In the mainstream part, the resultant force of this centrifugal force fo and the static pressure difference Δp is
Since the components of the Coriolis force are in the directions opposite to the component fc of the Coriolis force and cancel each other out, when the vector sum of the centrifugal force fo and the static pressure difference Δp is balanced with the component force fc of the Coriolis force, the vicinity of the hub 2 and the casing 1 is obtained. In the above, these unbalanced components can be reduced, and the generation of the secondary flow between the rows of the moving blades 40 can be suppressed.

The position of the reverse camber portion 41 is determined by the moving blade 4
It is set to be behind the vicinity of the center of the chord length at 0. In this case, in the part where the compression efficiency is high,
The centrifugal force fo and the static pressure difference Δp act to balance the whole body.

When the reverse camber portion 41 is formed by curving (meandering) the cross-sectional shape of the moving blade 40 to the ventral side, the wall thickness of the moving blade 40 substantially changes. Since it does not exist, the mechanical strength is less affected, and the compression ratio is set only by the shape of the inlet and the outlet of the moving blade 40, and therefore is not affected by the presence or absence of the reverse camber portion 41.

If the reverse camber portion 41 is provided with the convex surface 42 and the concave surface 43, the compressed air flow L is meandered by both of them, so that the sum of the centrifugal force fo and the static pressure difference Δp.
Then, the component force fc of the Coriolis force is canceled.

[0017]

The compressor blade according to the present invention has the following effects. (1) By disposing the reverse camber portion in a part of the moving blade, it is possible to suppress the generation of the secondary flow between the blades due to the Coriolis force and improve the compression efficiency. (2) By placing the reverse camber portion at a position rearward of the vicinity of the center of the chord length of the moving blade, centrifugal force or static pressure difference is applied to a portion where the compression efficiency is increased, and a component force of the Coriolis force is generated. It is possible to achieve balance between the two and to achieve even higher efficiency of the compressor. (3) Since the reverse camber portion is formed in a meandering state, it is possible to reduce the influence on the thickness of the wall of the moving blade and to improve the compression efficiency without affecting the compression ratio.

[Brief description of drawings]

FIG. 1 is a partially omitted development view showing an embodiment of a moving blade of a compressor according to the present invention.

FIG. 2 is a partially omitted perspective view showing an embodiment of a moving blade of a compressor according to the present invention.

FIG. 3 is a partially sectional front view showing a structural example of a compressor.

FIG. 4 is a diagram for explaining the influence of Coriolis force generated between blades.
FIG. 3 is a development view taken along line AA of FIG.

FIG. 5 is a side sectional view showing a secondary flow between blades based on Coriolis force.

[Explanation of symbols]

 1 Casing 2 Disk (hub) 3 Flow path 40 Moving blade 41 Reverse camber part 42 Convex surface 43 Concave surface fc Coriolis force component force fo Centrifugal force Δp Static pressure difference L Compressed air flow

Claims (3)

[Claims] 1. An inclined flow path (3) is formed between a casing (1) and a disk (2) which is rotationally driven so that an outlet is radially outward from an inlet, and a moving blade is formed on the disk. A compressor blade to be attached, wherein a reverse camber section (41) is arranged on a part of the rotor blade (40). 2. The reverse camber section (41) has a rotor blade (40).
The moving blade of the compressor according to claim 1, wherein the moving blade is disposed rearward of the vicinity of the center of the chord length of the compressor. 3. The reverse camber section (41) has a rotor blade (40).
The moving blade of the compressor according to claim 1 or 2, wherein the cross-sectional shape of the compressor is formed in a meandering shape.