JPH102300A - Turbo-fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent separation of an flow in a guide vane with the flow direction guided to an impeller in the nearly reverse direction to the flow direction in a housing peripheral flow path, of a plurality of the guide vanes. SOLUTION: Relating to guide vanes (d) to (i) with the direction of flow guided to an impeller 1 in the nearly reverse direction to the flow direction in a housing peripheral flow path 5, a vane shape, having a profile center line bending to the upstream side of a flow in the peripheral flow path 5 on a vane leading edge side, is provided. Relating to guide vanes (a) to (c) in a width D of a fluid inlet 6 of a housing 4, a vane shape, having a profile center line bending so as to make a vane leading edge face the fluid inlet 6 of the housing 4, is provided. Relating to guide vanes (j) to (q) except these vanes, a vane shape, having a linear profile center line, is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbo-type fluid machine such as a compressor or a blower for pressure-feeding a fluid.

[0002]

2. Description of the Related Art As a conventional turbo type fluid machine, for example, there is one shown in FIG. 10 (Japanese Patent Laid-Open No. Hei 7-30569).
No. 8). FIG. 10 is a cross-sectional view perpendicular to the axis of the suction side housing of the turbo fluid machine. The impeller 1 is a rotating shaft 2
It is fixed to and rotates.

A plurality of blades are arranged around the impeller 1 so as to form a circular cascade, and guide the flow to the impeller 1 in order to make the flow angle of the fluid into the impeller 1 appropriate. A guide wing 3 is provided. Therefore, each guide blade 3 has a predetermined inclination along the rotation direction of the impeller 1. The housing 4 that houses the impeller 1 and the guide vanes 3 forms an outer peripheral passage 5 around the guide vanes 3 and has a fluid inlet 6 at one location in the circumferential direction. The fluid inlet 6 is directed toward the center of the impeller 1, so that the flow directions on the left and right sides of the outer peripheral passage 5 are opposite to each other.

Accordingly, the fluid flowing from the fluid inlet 6 of the housing 4 flows through the outer peripheral flow path 5 of the housing 4 as shown in FIGS.
Flows in the two directions, and is turned by flowing between the guide vanes 3, and flows into the impeller 1 at the center.

[0005]

By the way, in such a conventional turbo type fluid machine, as shown in FIG. 11, the flow in two directions A and B in the outer peripheral flow path 5 of the housing 4 is shown. One of the flows (direction A in the figure) is
Only need to be turned by several tens of degrees, but the other side (illustrated B
Direction) must be turned more than 90 degrees by the guide vanes 3.

However, since all of the plurality of guide vanes have the same shape, the guide vane that turns 90 degrees or more with respect to the flow direction in the outer peripheral flow path of the housing does not flow along the guide vane, and the guide vane does not flow. Peels off from This allows
The pressure loss at the guide vanes increases, the pressure at the impeller inlet decreases, and the circumferential distribution (variation) of the pressure losses generated by the multiple guide vanes increases, and the circumferential flow distribution at the impeller inlet increases. There is a problem that the size is increased and the performance of the impeller is reduced.

SUMMARY OF THE INVENTION [0007] In view of the above-mentioned conventional problems, it is an object of the present invention to suppress flow separation, reduce pressure loss, and improve the efficiency of an impeller.

[0008]

According to the first aspect of the present invention, there is provided an impeller and a plurality of guides which are arranged around the impeller to form a circular cascade and guide the flow to the impeller. A turbo type comprising: a vane; and a housing having an outer peripheral flow path formed around these guide vanes, having a fluid inlet at one location in the circumferential direction, and having flow directions opposite to each other on the right and left sides of the outer peripheral flow path. In the fluid machine, of the plurality of guide vanes, for a guide vane in which the direction of flow guided to the impeller is substantially opposite to the direction of flow in the housing outer peripheral flow path, the flow of the flow in the outer peripheral flow path on the blade leading edge side. On the other hand, the airfoil has an airfoil centerline that is bent to the upstream side. It has a wing shape with lines.

That is, since the guide vane which turns the flow by 90 degrees or more is a blade shape having a bent airfoil centerline, the direction of the leading edge of the blade is close to the direction of the flow,
Since the turning angle at the leading edge side of the blade can be reduced, the fluid smoothly flows in, and the separation of the flow is suppressed, whereby the pressure loss can be suppressed. The airfoil center line refers to a line obtained by connecting points at which the distances to the upper surface and the lower surface of the airfoil are equal.

In the invention according to claim 2, the guide vane within the width of the fluid inlet of the housing has a wing shape having an airfoil centerline bent so that the leading edge of the vane faces the fluid inlet of the housing. Features. As described above, with respect to the guide blade near the fluid inlet of the housing, the flow can flow more smoothly and the pressure loss can be reduced by directing the leading edge of the blade toward the fluid inlet.

According to the third aspect of the present invention, the guide vane on the opposite side of the housing from the fluid inlet and the impeller is provided.
As for the airfoil shape with a straight airfoil center line, the number of guide airfoils with a straight airfoil center line in the guide vanes other than the guide airfoil within the width of the fluid inlet of the housing, and the bent airfoil center line as It is characterized by having more guide wings than it has.

In the outer peripheral flow path of the housing, the side flowing in the same direction as the direction of rotation of the flow flowing into the impeller and the side flowing in the opposite direction have smaller pressure loss than the side flowing in the same direction. The percentage increases. In view of this point, by increasing the number of guide vanes having a straight airfoil center line, the flow between the guide vanes can be made smoother in accordance with the flow rate in the housing outer peripheral flow path.

The invention according to claim 4 is characterized in that the blade length of the guide vane having the bent airfoil centerline is longer than the blade length of the guide blade having the straight airfoil centerline. In this way, the wing length of a guide wing with a bent airfoil centerline is
While the length of the guide vane should be long enough to secure a sufficient wing area for turning the flow largely, the length of the guide vane with a straight airfoil center line where flow separation is difficult to occur should be short, and the pressure loss due to the guide vane To reduce.

In the invention according to claim 5, the guide vane having a straight airfoil centerline adjacent to the guide vane having a bent airfoil centerline on the opposite side of the fluid inlet of the housing and the impeller. On the extension of the center line of the shape, a mountain-shaped projection is provided from the inner wall of the housing. By providing the mountain-shaped projections that partition the left and right flows of the housing outer peripheral flow path, the disturbance of the flow at the position where the counterclockwise and rightward flows merge is reduced, and the pressure loss due to this is reduced.

According to a sixth aspect of the present invention, in the invention according to the fifth aspect, among the guide vanes having a straight airfoil center line,
A guide wing corresponding to the chevron-shaped projection is characterized in that the leading edge side of the wing is extended to approach the tip of the projection. Thereby, the effect of separating the counterclockwise and counterclockwise flows in the outer peripheral flow path of the housing can be further enhanced.

In the invention according to claim 7, a guide piece having a shape conforming to the blade shape is provided in the vicinity of the negative pressure side curvature portion of at least a part of the guide blades having a bent airfoil center line. It is characterized by the following. A guide vane with a bent airfoil centerline turns the flow largely, so when used under conditions where the flow velocity between the guide vanes is large, the flow will separate on the negative pressure side, but a guide piece should be provided on the negative pressure side Thus, separation of the flow on the suction side of the guide vane can be suppressed.

The invention according to claim 8 is characterized in that the total distance between the rear end of each guide piece and two guide vanes adjacent thereto is larger than the throat width between the guide vanes.
By setting the rear end position of the guide piece so as to have such a relationship, the space between the trailing edges of the guide blades becomes the throat having the smallest flow path cross-sectional area, and the flow rate to be choked is limited by the guide piece. Disappears.

According to the ninth aspect of the present invention, at least a portion of the guide vanes having a bent airfoil center line protrudes from the inner wall of the housing toward the leading edge of the guide vane, and A guide portion having a concave R shape is provided on the same side. The guide vane with a bent airfoil center line turns the flow largely, so if used under conditions where the flow velocity between the guide vanes is large, the flow will separate on the negative pressure side, but the guide part provided on the housing side ,
Since the flow can be diverted before flowing into the guide vanes, the turning angle of the flow at the guide vanes is reduced, and separation of the flow on the suction side of the guide vanes can be suppressed.

[0019]

According to the first aspect of the present invention, the flow is set to 90
Even for blades that are turned more than one degree, flow separation is suppressed, which can reduce pressure loss, and the distribution (variation) of circumferential pressure loss is reduced,
The effect of improving the distribution of the circumferential flow rate flowing into the impeller and improving the efficiency of the impeller can be obtained.

According to the second aspect of the present invention, with respect to the guide vane within the width of the fluid inlet of the housing, the leading edge of the vane is directed toward the fluid inlet, so that the flow can flow more smoothly and the pressure loss can be reduced. . According to the third aspect of the present invention, the guide vane having a straight airfoil center line is formed as a blade shape having a straight airfoil center line with respect to the guide vane on the opposite side of the fluid inlet of the housing and the impeller. By increasing the number, the flow between the guide vanes can be made smoother in accordance with the flow rate ratio in the housing outer peripheral flow path.

According to the fourth aspect of the present invention, with respect to the guide vane having a bent airfoil center line, the blade length can be increased to secure a sufficient vane area for turning the flow largely, and For a guide vane having a straight airfoil centerline where separation does not easily occur, the blade length can be shortened to further reduce pressure loss. According to the invention according to claim 5, by providing the mountain-shaped projections that partition the left and right flow of the housing outer peripheral flow path, the disturbance of the flow at the position where the counterclockwise and clockwise flows merge is reduced, This can reduce the pressure loss.

According to the sixth aspect of the present invention, the guide wing corresponding to the chevron-shaped projection is extended and brought close to the tip of the projection, so that the counterclockwise and clockwise flows in the outer peripheral flow path of the housing. Can be further enhanced. According to the invention according to claim 7, by providing the guide piece near the suction side curvature portion of the guide vane having a bent airfoil center line, even if the flow velocity between the guide vanes is a large flow rate condition, Flow separation can be suppressed.

According to the eighth aspect of the present invention, it is possible to prevent the flow rate of choking from being restricted by the guide piece by setting the rear end position of the guide piece. According to the ninth aspect of the present invention, since the guide portion provided on the housing side can turn the flow before flowing into the guide vane, the turning angle of the flow at the guide vane becomes small, and Separation of the flow on the negative pressure side can be suppressed.

[0024]

Embodiments of the present invention will be described below. FIG. 1 shows a first embodiment of the present invention. The impeller 1 rotates while being fixed to the rotating shaft 2. Around the impeller 1, a plurality of guide vanes 3 are provided so as to form a circular cascade and guide the flow to the impeller 1.

The housing 4 containing the impeller 1 and the guide vanes 3 forms an outer peripheral passage 5 around the guide vanes 3 and has a fluid inlet 6 at one location in the circumferential direction. This fluid inlet 6
Are directed toward the center of the impeller 1 so that the flow directions are opposite to each other on the left and right sides of the outer peripheral passage 5. Here, of the plurality of guide vanes 3 (the position is indicated by a lowercase letter for explanation), the direction of the flow guided to the impeller 1 is substantially opposite to the direction of the flow in the housing outer peripheral flow path 5. The wings d to i have a wing shape having an airfoil center line bent at the leading edge side of the blade and upstream of the flow in the outer peripheral flow path 5. The bent portion of the center line of the airfoil is smoothly connected by R.

On the other hand, the guide blades l to q whose flow direction leading to the impeller 1 is almost forward with respect to the flow direction in the housing outer peripheral flow path 5, the fluid inlet 6 of the housing 4 and the impeller 1
The guide wings j and k on the opposite side of the wing have a wing shape having a straight airfoil center line. Further, the guide vanes a to c within the width (D) of the fluid inlet 6 of the housing 4 have a wing shape having an airfoil center line bent so that the leading edge of the vane faces the fluid inlet 6 of the housing 4.

As described above, the guide blades j and k on the opposite side of the fluid inlet 6 of the housing 4 and the impeller 1 have a wing shape having a straight airfoil center line.
Guide vane a within width (D) of fluid inlet 6 of housing 4
In the guide vanes d to q excluding -c, the number of guide vanes having a straight airfoil center line (eight of j to q) is reduced by the number of guide vanes having a bent airfoil center line (d to i). 6).

Further, the blade lengths of the guide vanes a to i having a bent airfoil center line are changed by the guide vanes j to j having a straight airfoil center line.
It is longer than the wing length of q. Next, the operation will be described. The guide blades di for turning the flow by 90 degrees or more have a bent airfoil center line, so that the leading edge of the blade is close to the flow direction, and the turning angle on the leading edge side of the blade is small. As a result, the fluid smoothly flows in and the flow separation is suppressed. Further, by smoothly connecting the bent portion of the airfoil center line with R, separation of fluid at the bent portion can be reduced. Thereby, pressure loss can be suppressed.

Therefore, since the distribution (variation) of the pressure loss in the circumferential direction is reduced, the distribution of the circumferential flow rate flowing into the impeller 1 can be improved, and the efficiency of the impeller 1 can be improved.
Increase the total flow rate when choking in the flow path between the guide vanes,
It is possible to widen the flow rate range that can be flowed by using the guide vanes. In the guide vanes j to q having a straight airfoil centerline, since the flow direction and the airfoil centerline almost match,
It flows in smoothly and pressure loss can be suppressed.

Further, as for the guide vanes a to c within the width (D) of the fluid inlet 6 of the housing 4, the flow smoothly flows in because the leading edge of the vane is directed toward the fluid inlet 6 of the housing 4. , The pressure loss can be reduced. Further, in the housing outer peripheral flow path 5, the side flowing in the opposite direction largely changes between the side flowing in the same direction as the rotation direction of the flow flowing into the impeller 1 and the side flowing in the opposite direction. Therefore, since the pressure loss is greater due to the side flowing in the same direction, the flow rate flowing in the same direction is larger than the flow rate flowing in the opposite direction. In view of this, the guide vanes d excluding the guide vanes a to c within the width (D) of the fluid inlet 6 of the housing 4.
Since the number of guide vanes j to q having a straight airfoil center line is larger than the number of guide vanes di to di having a bent airfoil center line in In accordance with the flow rate ratio, it is possible to smoothly flow between the guide vanes 3.

Further, since the lengths of the guide vanes a to i each having a bent airfoil center line are long, a sufficient blade area for turning the flow largely can be secured. Conversely, the blade lengths of the guide vanes j to q each having a straight airfoil center line in which flow separation is unlikely to occur are reduced, so that pressure loss due to the guide vanes can be reduced. 2 and 3 show a second embodiment of the present invention.

The description of the same configuration as in the first embodiment is omitted,
Only different configurations will be described. Fluid inlet 6 of housing 4
On the side opposite to the impeller 1 and the guide vane j having a straight vane center line adjacent to the guide vane i having a bent vane center line, the inner wall of the housing 4 Further, a chevron-shaped projection 7 that partitions the flow on the left and right is provided.

The side wall Bt on the left side of the projection 7 is oriented in accordance with the inclination of the guide blade j having a straight airfoil center line.
The right side wall Bm in the figure connects the inner wall of the housing 4 and the tip of the protrusion 7 in an R shape. Also, of the guide vanes j to q having a straight vane center line, the guide vane j corresponding to the mountain-shaped projection 7
As is clear from FIG. 3, the leading edge of the wing is extended to be close to the tip of the projection 7 (wing length L
f).

Next, the operation unique to the second embodiment will be described. The counterclockwise and clockwise flows of the housing outer peripheral flow path 5 are separated by the chevron-shaped projections 7 provided on the inner wall of the housing 4 and the guide vanes j with the blade length (Lf) extended. The turbulence of the flow at the position where the flows merge is reduced, and the pressure loss due to this is reduced.

Since the position where the counterclockwise and rightward flows merge can be fixed by the projection 7, the instability of the flow due to the unstable position of the merger is eliminated, and the direction of the flow flowing into the guide vanes is stabilized. , And the impeller 1 can achieve stable efficiency. By adjusting the side wall Bt of the mountain-shaped projection 7 to the inclination of the guide wing j having the straight airfoil center line,
The flow straightly enters the guide vane j having the straight airfoil center line, while the opposite side wall Bm has an R-shape, thereby having a bent airfoil center line at this portion. Separation of the flow on the negative pressure side of the guide vane i can be suppressed.

Thus, the flow becomes easier at the circumferential position where the counterclockwise and rightward flows merge, and the circumferential flow rate distribution (variation) is reduced. 4 to 6 show a third embodiment of the present invention.
Is shown. The description of the same configuration as that of the first embodiment will be omitted, and only different configurations will be described. A guide piece 8 having a shape conforming to the blade shape is provided in the vicinity of the negative pressure side curvature portion of at least some of the guide blades a to i having a bent airfoil center line.

Here, the rear end of each guide piece 8 is determined by the sum (L ₁ + L ₂ ) of the distances L ₁ and L ₂ between the rear end and two adjacent guide vanes. The position is set to be larger than the throat width S (see FIG. 6). Next, the operation unique to the third embodiment will be described. As shown in FIG. 5, the guide vanes 3 having a bent airfoil center line largely turn the flow, and therefore, when used under the condition that the flow velocity flowing between the guide vanes 3 is large, the flow is separated on the negative pressure side ( X part of FIG. 5).

On the other hand, as shown in FIG. 6, by providing the guide 8 on the negative pressure side, separation of the flow on the negative pressure side of the guide vane 3 is suppressed without increasing the length of the guide vane 8 so much. be able to. In addition, since the suction side of the guide piece 8 is larger than the suction side R of the guide blade 3, the separation of the flow on the suction side of the guide piece 8 is caused by the flow of the flow generated only in the case of the guide blade 3. It can be smaller than peeling.

The rear end of each guide piece 8 is determined by the sum of the distances L ₁ and L ₂ (L ₁ + L ₂ ) between the rear end and two adjacent guide vanes, and the throat between the guide vanes. Since the position is larger than the width S, the space between the trailing edges of the guide vanes 3 becomes the throat having the smallest flow path cross-sectional area, and the flow rate of choking is not limited by the guide pieces 8. 7 to 9 show a fourth embodiment of the present invention.

The description of the same configuration as in the first embodiment is omitted,
Only different configurations will be described. Among the guide vanes a to i having a bent airfoil center line, the guide vanes di to i outside the width of the fluid inlet 6 of the housing 4 are located before the vanes of each guide vane di to the inner wall of the housing 4. A guide portion 9 having a concave R shape is provided on the same side as each of the guide vanes di to i, protruding toward the edge.

That is, the guide portion 9 has an R-shaped surface that is concave on the same side as the guide blades di in the direction of flow in the housing outer peripheral flow path 5. EE section), the section is substantially triangular.
Here, the fluid flowing through the housing outer peripheral flow path 5 is:
The main flow flows in the circumferential direction in a flow path having a height H without guide vanes of the housing outer peripheral flow path 5 which is made larger by the height H than the guide vane height h, and sequentially passes through the cross section with the guide vanes 3 (d to i). The flow is diverted, turned by the guide section 9, and guided to the guide vanes 3 (d to i).

Next, the operation unique to the fourth embodiment will be described. The guide vane 3 having a bent airfoil center line causes a large turning of the flow, so that when the flow velocity flowing between the guide vanes 3 increases, the flow separates on the negative pressure side. However, as shown in FIG. Since the flow can be diverted before flowing into the guide vane 3 by the guide portion 9 provided on the side, the turning angle of the flow at the guide vane 3 becomes small, and the guide vane 3
Of the flow on the negative pressure side can be suppressed.

A guide portion 9 provided from the housing 4
Has a substantially triangular cross-sectional shape as shown in FIG.
The flow can be prevented from being separated downstream of the guide section 9, and an increase in pressure loss due to the guide section 9 can be suppressed. The guide portion 9 provided from the housing 4 can be manufactured at a low cost by being formed integrally with the housing 4 by casting or press molding.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is an enlarged view of a main part of FIG. 2;

FIG. 4 is a sectional view showing a third embodiment of the present invention.

FIG. 5 is a diagram showing a flow when there is no guide piece;

FIG. 6 is a diagram showing a flow when there is a guide piece;

FIG. 7 is a sectional view showing a fourth embodiment of the present invention.

FIG. 8 is an enlarged view of a main part of FIG. 7;

9 is a sectional view taken along line EE of FIG. 7 or FIG.

FIG. 10 is a sectional view showing a conventional example.

FIG. 11 is a diagram showing a turning angle in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Impeller 2 Rotating shaft 3 Guide vane (a-q) 4 Housing 5 Outer flow path 6 Fluid inlet 7 Projection 8 Guide piece 9 Guide part

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shogo Mariko 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Nissan Motor Co., Ltd.

Claims (9)

[Claims] 1. An impeller, a plurality of guide vanes arranged around the impeller so as to form a circular cascade to guide the flow to the impeller, and an outer peripheral flow path formed around these guide vanes. And a housing having a fluid inlet at one location in the circumferential direction, and a housing in which flow directions are opposite to each other on the left and right sides of the outer peripheral flow path, wherein the impeller of the plurality of guide vanes For the guide vane whose direction of flow to be guided is almost opposite to the direction of flow in the outer peripheral flow path, it has a wing shape with an airfoil centerline bent at the leading edge of the blade and upstream of the flow in the outer peripheral flow path. On the other hand, the guide wing, in which the direction of the flow guided to the impeller is substantially forward with respect to the direction of the flow in the outer peripheral flow path of the housing, has a wing shape having a straight airfoil center line. machine. 2. The guide vane within the width of the fluid inlet of the housing has a wing shape having an airfoil centerline whose leading edge is bent so as to face the fluid inlet of the housing. The turbo-type fluid machine as described. 3. The guide vane, which is located on the opposite side of the fluid inlet of the housing with respect to the impeller, has a straight airfoil center line, and has a shape other than the guide vane within the width of the fluid inlet of the housing. 3. The turbomachine according to claim 1, wherein the number of guide vanes having a straight airfoil centerline is larger than the number of guide vanes having a bent airfoil centerline. 4. The guide vane having a bent airfoil centerline has a blade length longer than that of a guide vane having a straight airfoil centerline. A turbo-type fluid machine according to any one of the preceding claims. 5. An extension of the airfoil centerline of the guide vane having a straight airfoil centerline adjacent to the guide vane having a bent airfoil centerline on the opposite side of the fluid inlet of the housing and the impeller. The turbo-type fluid machine according to any one of claims 1 to 4, wherein an angled projection is provided on an inner wall of the housing. 6. A guide wing having a straight airfoil centerline, wherein a guide wing corresponding to the chevron-shaped protrusion has a leading edge side thereof extended so as to be close to a tip of the protrusion. The turbo-type fluid machine according to claim 5, wherein: 7. A guide vane having a bent airfoil center line, in the vicinity of a suction-side curvature portion of at least a part of the guide vanes,
The turbo-type fluid machine according to any one of claims 1 to 6, wherein a guide piece having a shape along the wing shape is provided. 8. The turbo-type fluid according to claim 7, wherein the total distance between the rear end of each guide piece and two guide vanes adjacent thereto is larger than the throat width between the guide vanes. machine. 9. A guide vane having at least a part of a guide vane having a bent airfoil center line, the guide vane protruding from an inner wall of a housing toward a leading edge of the guide vane and being concave on the same side as the guide vane. The turbo type fluid machine according to any one of claims 1 to 8, further comprising a guide having a shape.