JPH01285700A - Impeller for turbo machine - Google Patents

Abstract

PURPOSE:To reduce the flow loss inside an impeller flow passage by providing a clearance for passing through from a blade surface toward a rear surface, on the part of a connecting part for connecting the blade end part of an impeller with a side plate and a side plate or a main board. CONSTITUTION:When an impeller with a side plate is rotated, the part of a fluid for flowing inside an impeller flow passage passes through the clearance 20 formed on the top end part of a blade 2 connecting to a side plate 1, so that leakage flow 21 is generated from a blade surface 2c toward a blade rear surface 2d. In the impeller flow passage, since flow passage eddies 6, 7 corresponding to the secondary flow for flowing from the surface 2c toward the rear surface 2d are respectively generated on a main plate 3 side and the side plate 1 side, a flow passage eddy 7 is opposed to the leakage flow 21 so as to weak the power. The high loss region 8 of fluid on the rear surface 2d or on the corner between the rear surface 2d and side plate 1, is carried to the spot apart from the corner part by the flow passage eddies 6, 7, and it is caused by changing the leakage flow 21 and the flow passage eddy 7, while energy is supplied by the leakage flow 21 at the same time. As the result, large pealing is prevented in the impeller with the clearance, so that the loss of flow is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a turbo fluid machine (hereinafter simply referred to as a turbo machine) including a centrifugal type or mixed flow type pump and blower.
In particular, the present invention relates to a device for reducing flow loss in a flow path of an impeller with a shroud.

(Prior Art) Conventionally, an impeller with a side plate for a turbomachine has a side plate 1, as shown in FIG. 7(a) and FIG. It is integrally attached to the main plate 3 via the blades 2 to constitute an impeller, and the impeller is housed in a casing (not shown) and is rotated in the direction of the arrow 4 by a main shaft attached to the main plate 3. It has become so.

During operation, fluid is sucked in from the impeller 2a in the direction of the arrow 5, and while passing through the impeller flow path formed by the adjacent blades 2, side plate 1, and main plate 3, the fluid is supported by energy, and the fluid flows through the impeller 2a. A casing (not shown) from the vehicle exit 2b (
discharged into the porlute chamber or guide casing).

In the impeller flow path, a boundary layer is formed along the inner surface of the side plate 1, and the flow flows in a vortex state outside the main flow in the direction of arrow 5 flowing from the population 2a toward the outlet 2b and within a cross section perpendicular to the main flow. A secondary flow is occurring.

(Problems to be Solved by the Invention) As described above, in the conventional impeller with side plates of a turbomachine, a boundary layer and a secondary flow occur in the impeller flow path during operation, and the secondary flow occurs in the impeller flow path. As shown in FIG. 7(b), the flow is from the blade surface 2C to the blade back surface 2d on the main plate 3 side.
There are two types of flow path vortices: a flow path vortex 6 that occurs toward the side plate 1, and a flow path vortex 7 that similarly occurs from the blade surface 2C toward the blade back surface 2d on the side plate 1 side.Normally, the flow path vortex 6 on the main plate 3 side It is larger than the side channel vortex 7.

As a result, a region 8 in which high-loss fluid accumulates is formed on the blade back surface (negative pressure surface) 2d or in a part of the corner between the blade back surface 2d and the side plate 1.
The deceleration of the flow is originally large, and for this reason, in the conventional impeller with side plates, together with the development of the boundary layer described above, this causes major flow separation in the region 8 and a sharp increase in loss due to this. The problem was that it was easy.

Due to the above-mentioned drawbacks, the loss inside the impeller increases, causing the impeller to stall in the partial flow range, and as a result, the broken line in the performance curve (head curve) in Figure 4 is extremely inconvenient for stable operation of the turbomachine. There was a problem in that it exhibited the upward instability characteristic of 9.

An object of the present invention is to solve the problems of the prior art described above and to provide an impeller with side plates that reduces flow loss in the impeller flow path.

[Means to solve the problem]

In order to achieve the above object, the present invention is characterized in that a gap penetrating from the front surface of the blade to the back surface thereof is provided in a part of the connecting portion between the blade end and the side plate or the main plate of an impeller with a side plate. There is.

The above-mentioned gap is preferably provided at the tip of the blade that connects to the side plate, or on the inner surface of the side plate that connects to the blade, and
It is also possible to provide it at the base of the blade that connects to the main plate or on the surface of the main plate that connects to the blade.

[For production]

Since the present invention is configured as described above, when the impeller with the side plate rotates during operation of the turbomachine, a part of the fluid flowing in the flow path of the impeller flows between the blade end portion and the side plate or the main plate. A flow leaks from the blade surface (pressure surface) toward the blade back surface (negative pressure surface) through a gap provided in a part of the connecting portion with the blade.

On the other hand, in the impeller flow path, similar to the conventional example described above (Fig. 7), flow path vortices corresponding to secondary flows flowing from the blade surface to the blade back surface are generated on the main plate side and the side plate side, respectively. ing. Therefore, if a gap that guides the leakage flow is provided at the tip of the blade that connects to the side plate, the flow path vortex on the side plate side among the flow path vortices faces the leakage flow, and its strength increases. The high loss region of the fluid that is weakened and formed on the back surface of the blade or a part of the corner between the back surface of the blade and the side plate by the two above-mentioned side-path vortices is caused by the leakage flow and changes in the flow path vortices. As it is transported to a remote location, energy is supplied by the leakage flow. As a result, large separation is prevented in the gapped impeller, and flow losses during partial flow operation of the impeller are reduced.

Further, when a gap is provided on the inner surface of the side plate connected to the blade, the same effect as described above is performed.

In addition, if a gap is provided on the base side of the blade that connects to the main plate, penetrating from the front surface of the blade to the back surface, the flow path vortex 6 on the main plate side shown in the conventional example (FIG. 7) described above The high loss region 8 formed by the two flow path vortices 6 and 7 is weak in the case of the above-mentioned case where the gap is provided on the blade tip side. Although there is a tendency for the blades to gather at the center of the back surface of the blade compared to the above, there is no major change in the fact that the leakage flow causes the high loss area to be carried away from a part of the corner, thereby preventing separation.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1(a) is a side sectional view of an impeller with a side plate showing a first embodiment of the present invention, FIG. 1(b) is a sectional view taken along line 1-1 in FIG. 1(a), and FIG. ) is an action explanatory diagram, and the seventh
The same reference numerals as those shown in FIGS. (a) and (b) indicate the same or similar parts.

In the figure, a side plate 1 is integrally attached to a main plate 3 via blades 2 to form an impeller. During operation, the main shaft attached to the main plate 3 rotates in the direction of arrow 4, and the fluid is transferred to the impeller. From the impeller outlet 2b, energy is applied while suction is sucked in the direction of the arrow 5 and passes through the impeller flow path formed by the adjacent blades 2, the side plate 1, and the main plate 3. The fact that it is discharged into a chamber or a guide casing is the same as in the conventional one (FIG. 7(a)).

However, in this embodiment, a gap 20 is provided at the tip of the blade 2 that connects to the side plate 1, penetrating from the front surface of the blade to the back surface of the blade.

With the configuration described above, when the impeller with the side plate rotates during operation of the turbomachine, a part of the fluid flowing in the impeller flow path is disposed at the tip of the blade 2 connected to the side plate 1. As shown in FIG. 1(c), a leakage flow 21 is generated from the blade surface (pressure surface) 2c toward the blade back surface (negative pressure surface) 2d through the gap 2o.

On the other hand, in the impeller flow path, the conventional example described above (Fig. 7(b)
)), flow path machines 6 and 7 corresponding to the secondary flow directed from the blade surface 2c to the blade back surface 2d are generated on the main plate 3 side and the side plate f1 side, respectively. The flow path device 7 on the first side faces the swollen flow 21 and its strength is weakened, and the two flow path devices 6 and 7 close the corner between the blade back surface 2d or the blade back surface 2d and the side plate 1. The high loss region 8 of the fluid formed at the corner is carried away from a part of the corner by the above-mentioned diversion flow 21 and the change in the flow path machine 7, and at the same time, energy is absorbed by the leakage flow 21. is supplied. As a result, large separation is prevented in the gapped impeller, and flow losses during partial flow operation of the impeller are reduced.

Therefore, according to this embodiment, since the flow loss can be reduced as described above, the head (H) shown in FIG.
- In the flow rate (Q) characteristic diagram, the upward-sloping unstable characteristic 9 on the head curve that occurs in the partial flow rate region is eliminated ζ, or the critical flow rate q at which the upward-sloping unstable characteristic begins to occur as shown in the head curve 10, It is possible to shift the flow rate to q2 on the low flow rate side, expand the flow rate range in which the turbomachine can make one stable turn, and improve the performance characteristics of the turbomachine.

FIG. 382 is a side sectional view showing the second embodiment of the present invention, and in the figure, the same reference numerals as those shown in FIG. 1(a) indicate the same parts.

In this embodiment, a gap 3 penetrating from the front surface of the blade to the back surface of the blade is
This embodiment differs from the first embodiment (FIG. 1) in that G is formed on the inner surface of the side plate 1 that connects to the blade 2.

According to this embodiment, the wet flow passes through the gap (passage) 30 provided on the inner surface of the side plate 1 so as to straddle the tip of the blade, and flows from the blade surface (pressure surface) to the blade back surface (negative pressure surface). Because of the flow (in a detour), compared to the first embodiment (FIG. 1) in which a gap 14 is provided directly at the tip of the blade 2, the flow is 2! However, the high-loss region formed by the flow path machine is carried away from the blade back surface by the leakage flow and changes in the flow path machine, and at the same time, the sludge is Almost the same effect as in the first embodiment described above, in which peeling is prevented by receiving energy supply, is achieved.

FIG. 3 is a side sectional view showing a third embodiment of the present invention in which a gap penetrating from the surface of the blade to the back surface of the blade is provided on the blade base side. The same reference numeral indicates the same part.

In this embodiment, a gap 4o penetrating from the front surface of the blade to the back surface of the blade is provided at the base of the blade 2 connected to the main plate 1.

In addition, the gap 40 is, as shown by the two-dot chain line in the same figure,
It may be provided on the surface of the main plate 3 connected to the blade 2 so as to penetrate from the front surface of the blade to the back surface thereof.

According to these embodiments, FIG. 1(e) of the 's1 embodiment
The flow path device 6 on the main plate 3 side shown in 2 faces the leakage flow from the gap 40 or 50 provided on the base side of the blade 2, and its strength is weakened. The high loss region 8 formed by the road machines 6 and 7 tends to gather on the back surface 2d of the blade, compared to the case where a gap is provided on the blade tip side as in the first and second embodiments. but,
There is no essential change in the fact that the leakage flow moves the high loss region away from the corner portion and prevents separation.

Note that the technology of the present invention, which reduces loss in the blade flow path by providing a gap penetrating from the front surface of the blade to the back surface thereof, can also be applied to a differential user installed on the discharge side of the impeller of a turbomachine. . In this case, Fig. 5(a) and V
As shown in FIG. 3(b), which is a cross-sectional view taken along the -V line, the outer casing 11 and the inner casing 13 are integrally disposed via the diffuser blade 12 on the downstream side of the impeller main plate 3, A tip connected to the outer casing 11 of the differential user vane 12, which converts velocity energy into pressure energy while rectifying the fluid discharged from the impeller in the axial direction, and is discharged from the discharge port of the turbomachine. A gap 14 penetrating from the front surface of the diffuser blade to the back surface thereof is provided in the portion.

Therefore, when the impeller rotates, as the impeller rotates in the direction of the arrow 4, the leakage flow from the tip of the blade blows out from the gap 14 from the pressure surface 12c side of the differential user blade 12 toward the negative pressure surface 12d side causes the adjacent differential user to FIG. 5 (
A secondary flow 15 swirling in the same direction as the rotation direction 4 of the impeller is generated in the diffuser vane flow path shown in b).

This eliminates the large separation area 18 shown by the broken line in FIG.
a becomes a small peeled area 16 as shown by the solid line. In this way, it is possible to suppress separation of soaked particles at the diffuser blade portion and reduce flow loss.

As shown in FIG. 6, the above-mentioned gap 14 at the tip of the differential user blade can be replaced with a gap 24 penetrating from the front surface of the blade to the back surface of the outer casing 11 connected to the differential user blade.

In this case as well, substantially the same effect as that shown in FIG. 5 above can be achieved.

[Effects of the Invention] As explained above, according to the present invention, a gap penetrating from the front surface of the blade to the back surface thereof is provided in a part of the connecting portion between the blade end of the impeller with a side plate and the side plate or the main plate. By doing so, flow loss during partial flow operation of the impeller can be reduced and stalling of the impeller can be prevented. Therefore, in the head-flow characteristic diagram, it is possible to eliminate the upward-sloping unstable characteristic that occurs in the partial flow rate region, or to shift the critical flow rate at which the unstable characteristic begins to occur to the low flow rate side, and the turbomachine is The key is to expand the range of flow rates that can be operated stably.

The above effect can be achieved by providing a gap penetrating from the front surface of the blade to the back surface of the blade at the tip of the blade, or on the inner surface of the side plate connected to the tip, or at the base of the blade or the surface of the main plate connected to the base. For those provided, it is played in the same way as Habo.

[Brief explanation of the drawing]

FIGS. 1(a), (b), and (C) are a side sectional view, an I-I line sectional view, and an action explanatory diagram of a main impeller with a side plate showing a first embodiment of the present invention, and FIGS. 2 and 3. The figure shows the second and 's of the present invention.
4 is a head-flow characteristic diagram, and FIGS. 5(a), (b), and 6 are side sectional views of the differential user, a V-V line sectional view, and the same side sectional view. Figure, Figure 7(a)
and (b) is a side cross-sectional view and a cross-sectional view taken along the line ■-■ showing the conventional example. 1...Side plate, 2...Blade, 3...Main plate, 6,7.
... Channel machine, 20, 30. 40, 50... Jinma, 21...
・Flowing flow. Figure 1 (b) (C) Figure 2 Figure 3 Figure 4 Limit 1 Lightning Figure 5 Figure 7 (α) (b)

Claims (1)

[Claims] 1. In a turbomachine, a gap is provided in a part of the connection between the blade end of the impeller with a side plate and the side plate or the main plate, penetrating from the front surface of the blade to the back surface of the blade, and An impeller for a turbomachine characterized by reducing flow loss. 2. The impeller for a turbomachine according to claim 1, wherein a gap is provided at the tip of the blade connected to the side plate, penetrating from the front surface of the blade to the back surface thereof. 3. The impeller for a turbomachine according to claim 1, wherein the inner surface of the side plate connected to the blade is provided with a gap penetrating from the front surface of the blade to the back surface thereof. 4. An impeller for a turbomachine, characterized in that a gap is provided at the base of the blade connected to the main plate, penetrating from the front surface of the blade to the back surface thereof. 5. An impeller for a turbomachine, characterized in that a gap is provided on the surface of the main plate connected to the blade, penetrating from the front surface of the blade to the back surface thereof.