JPH0357900A - Variable type diffuser with vane - Google Patents

Abstract

PURPOSE:To improve the efficiency of a diffuser and stabilize the performance and also, miniaturize a drive machine, by providing advanceably/retreatably a front edge forming member at the groove of a vane main body fixed at a diffuser casing. CONSTITUTION:At the time of a rating operation in which the revolution number of a gas turbine is high, a pin 16 butts the front end of the 2nd groove 14, and a front edge forming member 15 is retained in a condition in which it projects from a vane main body 12, and the fitting angle beta of a vanell fits to the inflow angle alpha of a rating revolution number. Meanwhile, at the time of operation in which revolution is lower than the rating revolution, a hydraulic cylinder 25 is operated, and a space between both end portions 32 of a drive ring 30 is widened somewhat through a link bar 21. Then, the diameter of the ring 30 is enlarged, and the putting in pin 16 of the putting in hole 31 of the ring 30 retreats to the rear end of the 2nd groove 14, and the fitting angle betaof the vane 11 changes as the forming member 15 retreats somewhat to a lower stream A side. That is, the change of the inflow angle alpha can be coped with by changing the fitting angle beta, so the efficiency of a diffuser 4 is improved.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a diffuser that is disposed on the outlet side of a centrifugal compressor to recover the pressure of a working fluid, and in particular, relates to a diffuser that is disposed on the outlet side of a centrifugal compressor and restores the pressure of a working fluid. This invention relates to a diffuser with type vanes.

[Prior Art] First, a centrifugal compressor equipped with a fixed vane diffuser will be described.

In Fig. 6, 1 is a centrifugal impeller, 2 is a shroud,
3 is the hub. 4 is a radial type diffuser, which is placed on the outlet side of the centrifugal impeller 1. This diffuser 4 is constructed by arranging a large number of approximately triangular vanes 5 in the circumferential direction B in a diffuser casing 6, the thickness t of which increases in the circumferential direction B toward the outside in the radial direction (downstream A) in FIG. A fluid passage 7 is formed between the two vanes 5. Each of the vanes 5 is designed such that the mounting angle β (angle with respect to the tangent H) of the vane 5 matches the inflow angle α (the angle between the absolute velocity C of the flow and the circumferential velocity Cu) at the rated rotation speed of the gas star pin. It is set to . This mounting angle β
By matching the inflow angle α, the efficiency of the diffuser 4 is improved.

However, in the fixed type vane 5, since the mounting angle β is constant, the inflow angle α and the mounting angle β do not match until the rotation speed increases to the rated speed, and therefore the efficiency of the diffuser 4 is reduced. is low. Therefore, variable vane diffusers that can change the vane mounting angle β have been proposed (for example, Japanese Patent Laid-Open No. 55-1
(See Publication No. 25399). This kind of diffuser is the 8th
9 and 9.

In FIG. 8, 5A is a variable vane, which is rotatably attached to the diffuser casing 6. The motor 8 slightly rotates the variable vane 5A via a gear 9 as shown by the dashed line in FIG. 9, thereby changing its mounting angle β.

In this way, with the variable vane diffuser, by changing the mounting angle β, the mounting angle β can be adapted to the inflow angle α (see Fig. 7) even below the rated rotation speed.
The efficiency of the diffuser 4 can be improved. Furthermore, at the rated rotational speed, there is an advantage that the flow rate or pressure can be changed by changing the mounting angle β.

[Problems to be Solved by the Invention] However, in the diffuser with a variable vane, since the vane 5A rotates, it is necessary to provide a clearance between the diffuser casing 6 and the vane 5A in FIG. It is unavoidable that a gap S will occur.
Therefore, the efficiency of the diffuser 4 decreases. Furthermore, since the spacing S is provided, the vane 5A cannot be firmly fixed, and as a result, the vane 5A shown in FIG. 9 vibrates (the mounting angle β fluctuates), causing variations in the performance of the diffuser 4. Furthermore, in the above-mentioned conventional technology, since the entire vane 5A is rotated, a relatively large driving force is required, so the motor 8 becomes large.

Therefore, the first object of the present invention is to improve the efficiency of the diffuser, stabilize the diffuser performance, and downsize the drive machine. Further, in the conventional diffuser with variable vanes, many gears 9, bearings 10, etc. are used in addition to the motor 8 shown in FIG. 8, so the drive mechanism becomes complicated.

Therefore, a second object of the present invention is to provide a variable vane-equipped diffuser with a simple drive mechanism. [Means for Solving the Problems] In order to achieve the first object, the present invention first includes a vane body fixed to a diffuser casing, and a vane provided on the vane body in the fluid flow direction. The vane includes a groove extending along the vane, and a leading edge forming member that is fitted into the groove so as to be movable back and forth to form the leading edge of the vane. moreover,
A drive mechanism is provided that moves the leading edge forming member forward and backward to change the mounting angle of the vane.

Further, in order to achieve the second object, the present invention includes a drive mechanism that is first provided in the leading edge forming member and that protrudes outward through the diffuser casing, and each pin is fitted into the pin. It has a C-shaped drive ring with a fitting hole to be fitted. Furthermore, the drive mechanism moves the pin in a direction along the groove of the diffuser by moving the opposing ends of the C-shaped drive ring toward and away from each other to change the diameter of the drive ring. It is equipped with a drive machine that moves the leading edge forming member forward and backward.

[Function] According to the present invention, the vane body is provided with a groove along the fluid flow direction, and the leading edge forming member is fitted into this groove so as to be able to move forward and backward, so that by moving the leading edge forming member forward and backward, The mounting angle of the vane can be changed. Here, since the large vane main body is fixed to the diffuser casing, it is only necessary to form a gap between the small leading edge forming member and the diffuser casing. Therefore, the range in which gaps occur can be reduced.

Furthermore, since only the small leading edge forming member is moved back and forth, the vane can be held more stably than if the entire vane were rotated, and the driving force is reduced. In addition, the drive mechanism moves the pins provided on the leading edge forming member in the direction along the groove of the diffuser by moving both ends of the C-shaped drive ring toward and away from each other, thereby forming the leading edge. Move the member forward and backward within the groove of the vane body. Therefore, the number of driving machines is reduced and no bearings or gears are required.

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

1 to 4 show a first embodiment of this invention. In FIG. 1, the diffuser casing 6 is composed of a mounting plate 6a and a back plate 6b. The vane main body 12 is integrally formed with the back plate 6b, for example, by machining. As shown in FIG. 2, this vane body t2 is provided with a narrow first groove 13 extending along the fluid flow direction A. On the downstream A side of the first groove 13 in the vane main body 12, a first
A second groove 14 wider than the groove 13 is formed.

In this embodiment, these grooves 13 and l4 are
It is provided on the center line CL of 1. Note that an elongated hole 6al having the same shape as the second groove 14 is also formed in the mounting plate }-6a of FIG.

In FIG. 2, reference numeral 15 denotes a front edge forming member, which is fitted into the first groove 1-3 so as to be able to move forward and backward, and an edge portion 15a protruding from the main body 12 of the basin has a sharp shape. (
(See Figure 3). On the downstream A side of this leading edge forming member 15,
A pin 16 is fixed, and as shown in FIG. 1, this pin 16 passes through a long hole Sat in the mounting plate 6a and projects from the mounting plate 6a. The leading edge forming member 1
The width W1 of the vane 5 is set slightly smaller than the width W2 of the vane body 12 and the fluid passage 7, so that it can be moved forward and backward without being pinched between the mounting plate 6a and the back plate 6b. It has become. The vane body 12
and the leading edge forming member 15 constitute the vane 11 (
(See Figure 3). Reference numeral 20 in FIG. 1 is a casing for a gas star pin, and a hydraulic cylinder 2 is provided outside this casing 20.
5 is provided. 21 is a link bar, and as shown in FIG. 3, one end 21a of one ring bar 21 is fixed to the mounting plate 6a, and one end 21a of the other link bar 21 is
1a is connected to the rod 25a of the hydraulic cylinder 25, and the driving machine 22 is connected to the rod 25a of the hydraulic cylinder 25 shown in FIG.
The other ends 2lb of both linkers 21 are engaged with both ends 32 of the drive ring 30 shown in FIG.

The drive ring 30 has an approximately C shape with a part of an annular plate cut out.
It has a large number of fitting holes 31 into which the pins 16 are fitted, and is housed in the casing 20 of the gas star pin shown in FIG. As shown in FIGS. 4 and 3, the linker 21 changes the diameter of the drive ring 30 by moving the opposing ends 32 of the drive ring 30 toward and away from each other. For example, if the diameter of the drive ring 30 is 30 cm, the diameter is changed by 2 to 6 mm. Due to this slight change in diameter, the leading edge forming member 15 moves back and forth within the first groove 13 by 1 to 3 inches via the pin 16. A drive mechanism 23 is composed of the drive ring 30, the pin 16, and the axle drive machine 22 shown in FIG.

The fitting hole 31 of the drive ring 30 shown in FIG. 3 changes slightly in circumferential position as the ends 32 of the drive ring 30 are brought into contact with each other, so in order to absorb this change, The hole is slightly larger than the pin 16.

In addition, 24 in Fig. 1 is a seal ring, and the link part 21
and the casing 20 of the gas star pin. The rest of the configuration is the same as the conventional example shown in FIG. 6, and the same or equivalent parts are given the same reference numerals and detailed explanation thereof will be omitted. Next, the operation of the above configuration will be explained.

First, during rated operation with a high rotational speed of the gaster pin, the pin 16 shown in FIG.
The state that greatly protrudes from 2 is maintained. In this case, the mounting angle β of the vane 11 is the inflow angle α(
(See Figure 7). On the other hand, when operating at a rotation lower than the rated rotation, the hydraulic cylinder 25 shown in FIG.
4, the distance between both ends 32 of the drive ring 30 in FIG. 3 is slightly widened as shown in FIG. As a result, the diameter of the drive ring 30 becomes larger, and the fitting hole 3 of the drive ring 30 becomes larger.
The pin 16 that fits into the second groove 14 retreats to the rear end of the second groove 14, and the leading edge forming member 15 retreats slightly toward the downstream A side. As the leading edge forming member 15 retreats in this manner, the mounting angle β of the vane 11 in FIG. 2 changes. That is, as the protruding end of the leading edge forming member 15 retreats from point P to point Pl, the mounting angle β of the vane 1l increases to the mounting angle β1. In this way, the present invention achieves the inflow angle α(
(Fig. 7), the efficiency of the diffuser 4 is improved. Of course, the flow rate or pressure can also be changed by changing the mounting angle β at the rated rotation speed. In the above configuration, the present invention provides a large vane body 12
Since it is integrally formed with the back plate 6b, it is only necessary to form the space S between the edge portion 15a of the small leading edge shape member 15 and the diffuser casing 6 shown in FIG. Therefore, the area where the gap S occurs becomes extremely small, improving the efficiency of the diffuser 4. Also,
Since the vane main body 12 is integrally attached to the back plate 6b, it does not vibrate, and therefore, it becomes easy to maintain the mounting angle β of the vane 11 in FIG. 2 at a required angle. As a result, diffuser performance improves. Furthermore, since the mounting angle β of the vane 11 changes by moving only the small leading edge forming member 15 back and forth, the driving force of the hydraulic cylinder 25 shown in FIG. 1 can be reduced.

Therefore, since the hydraulic cylinder 25 can be made compact, the entire diffuser 4 can be made lightweight, making it suitable as a gas star pin for aircraft. For m-movement m+I423, pin 16, C type WAwJ
It is composed of a ring 30, a linker 21, etc., and does not use the gear 9 or bearing 10 shown in FIG. 8, resulting in a simple structure.

Note that conventionally, the vane was divided into two parts (for example,
(See FIG. 7 of Japanese Unexamined Patent Publication No. 55-1 25399) is known, but this invention differs from the vane 11 shown in FIG. 1 in that the entire vane rotates in this prior art. Therefore, it does not have the effect of this invention.

By the way, since the inside of the diffuser 4 is under high pressure, compressed air passes through the long hole 6al of the mounting plate 6a of FIG. However, since the space between the casing 20 of the gas star pin and the rod 25a is sealed, compressed air will not leak from the space 35 to the outside. There is no problem, so there is no problem. Note that although both grooves 13 and 14 in FIG. 2 are provided on the center line CL, they do not necessarily need to be provided on the center line CL.

Next, a second embodiment of the invention will be described.

In FIG. 5, a C-shaped drive ring 30 is made of a leaf spring and is suitable for a case where the stroke between both ends 32 is large.

The tip 15b of the leading edge forming member 15 has a curved line that recedes toward the downstream A side toward the center in the width direction W.

By the way, at the center in the width direction W, the radial division Cr of the flow in FIG. 2 is larger than at the ends affected by the boundary layer, so the inflow angle α (FIG. 7) becomes larger. Therefore, the fifth
By making the tip 15b of the leading edge forming member 15 shown in the figure into the above-mentioned curve, the mounting angle β (see FIG. 2) increases as it goes toward the center in the width direction W. is adapted to the inflow angle α (Fig. 7). Therefore, the efficiency of the diffuser 4 is further improved. Note that it is not necessary to use the C-shaped drive ring 30 shown in FIGS. 3 or 5 as the drive mechanism, and other mechanisms may be used.

[Effects of the Invention] As explained above, according to the present invention, the vane body is fixed to the diffuser casing, and the leading edge forming member is provided in the groove of the vane body so as to be able to move forward and backward, so that the efficiency of the diffuser can be improved. The diffuser performance can be improved, the diffuser performance can be stabilized, and the driving machine can be downsized.

In addition, the drive mechanism moves both ends of the C-shaped drive ring toward and away from each other to change the diameter of the drive ring, allowing the leading edge forming member to move forward and backward through the pin, resulting in a simple structure for the drive mechanism. Become.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a diffuser showing a first embodiment of the present invention, and FIG. 2 is the same as that of FIG. 1! ! -■ line sectional view, Figure 3 is a partially cutaway perspective view of the diffuser during rated operation,
FIG. 4 is a partially cutaway perspective view of the diffuser at low rotation speed, FIG. 5 is a partially cutaway perspective view of the diffuser according to the second embodiment, and FIG. 6 is a longitudinal sectional view of a conventional diffuser with fixed vanes. Figure 7 is a sectional view taken along the line ■-■ in Figure 6.
The figure is a vertical cross-sectional view of a conventional diffuser with variable vanes.
FIG. 9 is a sectional view taken along the line DC-IX in FIG. 8.

Claims (2)

[Claims] (1) A diffuser disposed on the outlet side of a centrifugal impeller, in which a large number of approximately triangular vanes whose circumferential thickness increases as they go downstream are arranged circumferentially in the diffuser casing, A fluid passage is formed between two adjacent vanes, and the vane includes a vane body fixed to the diffuser casing, a groove provided in the vane body and extending along the fluid flow direction, and a groove in the groove. A variable vane comprising: a leading edge forming member that is fitted in a manner that is movable forward and backward to form a leading edge of the vane, and further comprising a drive mechanism that changes the mounting angle of the vane by moving the leading edge forming member forward and backward; with diffuser. (2) In claim 1, the drive mechanism includes a pin provided on each of the leading edge forming members and protruding outward through the diffuser casing, and a fitting hole into which each pin is fitted. The leading edge is formed by moving the pin along a groove provided in the diffuser by changing the diameter of the driving ring by moving opposite ends of the driving ring toward and away from each other. A diffuser with a variable vane that has a drive machine that moves the member forward and backward.