JP2003021099A - Diffuser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diffuser capable of improving pressure recovery while suppressing increase of size of the diffuser and increase of flow peeling and abrasion resistance. SOLUTION: This diffuser has a splitter comprising a plurality of plate members circumferentially divided to a plurality of flow channels in a diffuser body formed of a hollow member expanding from an inlet opening toward an outlet opening along the central axis. In the plate members, parts about the central axis adjacent to the inlet opening are cut out. An expanding angle in each divided flow channel is smaller than the case having no splitter to suppress flow peeling, and speed reduction ratio of the diffuser can be increased without reducing performance. Additionally, the notches are disposed about the central axis having less turning flow, thereby reducing contact areas between the plate members and fluid to extremely reduce the abrasion resistance and improving the pressure recovery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffuser having a splitter inside.

[0002]

2. Description of the Related Art A diffuser is installed in a pipe for the purpose of recovering a joint or a pressure of a pipe having a different diameter. FIG. 8 is a perspective view of an example of a conventional diffuser, and FIG. 9 is another example.

In FIG. 8, the diffuser 100 is provided with a hollow truncated cone-shaped diffuser body 102 which is opened from an inlet opening 102a toward an outlet opening 102b.

The inlet opening 102a is connected to an outlet port of a fluid supply source (not shown) such as a compressor or a pump via an inlet conduit (not shown), and the outlet opening 102b is supplied from the fluid supply source via an outlet conduit (not shown). Connected to a device that uses the gas or liquid (hereinafter, referred to as “utilization device”).

The fluid a supplied into the diffuser main body 102 through the inlet opening 102a is the diffuser main body 10
Since the flow passage area in 2 increases along the flow direction, the flow velocity gradually decreases, and the pressure gradually increases accordingly. The fluid a, the pressure of which is increased by the diffuser 100, is supplied from the outlet opening portion 102b of the diffuser body 102 to the utilization device through the outlet conduit.

In order to increase the pressure recovery in the diffuser 100, the reduction ratio may be increased, that is, the area ratio of the outlet opening 102b to the inlet opening 102a of the diffuser body 102 may be increased.
For that purpose, the spread angle of the diffuser 100 may be increased, but if it is set too large, the flow is separated from the wall surface, and on the contrary, there is a problem that the performance of the diffuser 100 deteriorates and the pressure recovery decreases.

The diffuser body 102 has its center axis X
By increasing the length in the direction, it is possible to increase the reduction ratio without increasing the spread angle of the diffuser 100, but the diffuser 100 increases in size, resulting in an increase in manufacturing cost, or in the case of a pipe to be specifically applied. Depending on the shape, it may not be possible to install the long diffuser 100.

In the present specification, the "divergence angle" refers to a flow passage calculated as a complete truncated cone shape using an equivalent diameter calculated from the area of the inlet and the outlet of the flow passage. It is defined as the spread angle.

For example, considering the diffuser 100,
Considering the areas of the inlet opening 102a and the outlet opening 102b of the diffuser body 102, the inlet opening 102a and the outlet opening 102b are considered to be equivalent circles, and the diffuser body 102 is a perfect truncated cone whose axis is symmetrical with respect to the central axis X. Assuming that the diffuser body 102 is cut along a plane including the central axis X in the longitudinal direction, the angle between the inner peripheral surface of the diffuser body 102 and the plane intersects with the spread angle of the diffuser body 102. Become.

As an example of the prior art for increasing the reduction ratio without increasing the length of the diffuser in the direction of the central axis X and without deteriorating the performance, a splitter 204 is installed in the diffuser 200 as shown in FIG. Some have been inserted.

In FIG. 9, the diffuser 200 has a diffuser body 202 having an inlet opening 202a and an outlet opening 202b.
A splitter 204 composed of two flat plates is provided in the unit 2. The splitter 204 and the diffuser body 202
Since the inside of the diffuser 200 is divided into a plurality of flow paths and the spread angle of each flow path becomes smaller than that in the case where the splitter 204 is not provided,
The flow separation is suppressed and the diffuser performance is improved.

[0012]

However, when the number of splitters 204 to be inserted is increased, the diffuser 2
Since the contact area with the fluid a flowing in 00 increases, the friction loss increases, and as a result, the diffuser 2
The performance of 00 is degraded. Also, for example, the entrance opening 20
When a swirl flow exists at the inlet of the diffuser 200, such as when a rotating machine such as a compressor exists near 2a, the swirl flow collides with the splitter 204 to cause a loss, which deteriorates the performance of the diffuser 200. There is also the problem of doing.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the prior art and to provide a diffuser capable of improving pressure recovery while suppressing an increase in the size of the diffuser, flow separation and increase in frictional resistance. Is.

[0014]

Means for Solving the Problems (1) The present invention has been made to solve the above-mentioned problems. As a first means thereof, a central axis line extends from an inlet opening to an outlet opening. A diffuser body composed of a hollow member that expands along the inside is provided with a splitter formed of a plurality of plate members that are divided into a plurality of flow paths in the circumferential direction, and the plate member is provided around the central axis adjacent to the inlet opening. Provided is a diffuser characterized in that a part is cut out.

With the above arrangement, according to the first means,
The divergence angle in each of the divided flow paths is smaller than that without the splitter, flow separation is suppressed, and the reduction ratio of the diffuser can be increased without deteriorating the performance. Since the notch is provided around the central axis where the flow is small, the contact area between the plate member and the fluid is reduced, the frictional resistance can be significantly reduced, and the pressure recovery can be improved.

(2) As a second means, in the diffuser of the first means, an inclination forming a refraction plane at a portion adjacent to the inlet opening of the plate member and in contact with the inner peripheral surface of the diffuser body. Provided is a diffuser characterized by being formed with a portion.

According to the second means, in addition to the action of the diffuser of the first means, the inclined portion of the plate member adjacent to the inlet opening makes the pressure more effective against the swirling flow of the fluid flowing into the diffuser. Recovery is possible.

(3) As a third means, in the diffuser of the second means, there is provided a diffuser characterized in that the inclined portion is formed to have a curved curved surface.

According to the third means, in addition to the function of the diffuser of the second means, since the inclined portion has a curved curved surface, the tip of the inclined portion can be directed in the turning direction with a smaller inclination angle. Further, the swirling flow of the fluid flowing into the inclined portion can be smoothly converted in the direction of the central axis, which enables more effective pressure recovery.

(4) As a fourth means, in the diffuser of the second means or the third means, the inclined portion is pivotally supported by the plate member so as to be tiltable, and is also provided between the inclined portion and the diffuser body. There is provided a diffuser characterized by comprising a fixing means for an inclined portion.

According to the fourth means, in addition to the action of the diffuser of the second means or the third means, the inclination angle can be adjusted according to the size of the swirling flow of the fluid flowing into the inclined portion. More effective pressure recovery is possible for swirling flows with a wide range of inflow angles.

(5) As a fifth means, in the diffuser of the second means or the third means, the tilted portion is pivotally supported by the plate member so as to be tiltable, and locked by a link mechanism. Provided is a diffuser characterized in that all the same inclined portions are configured to be tilt-driven at the same time.

According to the fifth means, in addition to the action of the diffuser of the second means or the third means, the inclination angle can be adjusted all at once in accordance with the size of the swirling flow of the fluid flowing into the inclined portion. Therefore, it is possible to efficiently respond to the change of the inflow angle of the swirling flow having a wide inflow angle, and it is possible to effectively recover the pressure.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A diffuser according to a first embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view of the diffuser of the present embodiment, and FIG. 2 is a plan view taken along the line AA in FIG. FIG. 7 is a graph showing the radial distribution of the size of a general swirling flow in a diffuser.

The diffuser 10 of this embodiment has an inlet opening 12a and an outlet opening 12b.
The diffuser body 12 has a substantially frustoconical shape that expands along the central axis X from the opening 2a toward the outlet opening 12b.

A splitter 1 is provided in the diffuser body 12.
4 is provided, and the splitter 14 is composed of a plurality of plate members arranged in a radial shape with one side in contact with each other in the central axis line X of the diffuser body 12, and in FIG. It is composed of a plate member 16.

Further, the plate member 16 has an inlet opening 12a.
A notch 17 is formed around the center axis X of
The depth is about 1/3 of the length of the diffuser body 12 in the central axis X direction. This reduces the number of flow passages divided by the splitter 14 in the vicinity of the inlet opening 12a inside the diffuser body 12,
The reduction ratio is increased by increasing the divergence angle relatively, and conversely, the splitter 1 is provided near the outlet opening 12b.
This is because the number of flow passages divided by 2 is increased to relatively reduce the spread angle and reduce the reduction ratio. This allows
The flow separation can be suppressed to reduce the loss, and the pressure can be efficiently recovered.

Generally, in the inlet part of the diffuser, for example, the diffuser 100 of the conventional example shown in FIG. 8, the boundary layer does not develop much in the vicinity of the inlet opening 102a in the diffuser body 102, and the loss is small, so that the pressure is reduced. Can be efficiently recovered, but the outlet opening 10
In the vicinity of 2b, since the boundary layer develops, the loss becomes large, and the pressure tends to be unable to be recovered.

Therefore, in the diffuser inlet portion where the loss is small, the reduction ratio is increased (the spread angle is increased) to efficiently recover the pressure, and in the outlet portion where the loss is large, the spread angle of the diffuser is reduced to separate the flow. It is advantageous to suppress the loss to minimize the loss.

Therefore, in the present embodiment, as shown in FIG. 1, the number of flow passages divided by the splitter 14 is reduced in the vicinity of the inlet opening 12a inside the diffuser body 12 and the divergence angle is relatively increased. The reduction ratio is increased, and conversely, in the vicinity of the outlet opening 12b, the splitter 14
The number of divided channels is increased to relatively reduce the divergence angle. As a result, flow separation can be suppressed, loss can be reduced, and pressure can be efficiently recovered.

Further, when there is a swirl flow at the inlet of the diffuser 10, flow separation is less likely to occur as compared with the case where there is no swirl flow, so even if the divergence angle is increased a little, the performance does not deteriorate and the deceleration is reduced. The ratio can be increased. Therefore,
When there is a swirl flow at the inlet of the diffuser 10, the number of flow passages divided by the splitter 14 near the inlet opening 12a of the diffuser body 12 is reduced, and the spread angle is relatively increased to reduce the reduction ratio. The size of the diffuser 10 is increased and the performance of the diffuser 10 can be improved.

Further, as shown in the graph of the radial distribution of the general swirl flow magnitude in the diffuser in FIG. 7, almost no swirl flow is generated at the center of the diffuser, but the peripheral part, that is, the radial direction from the center. The turning angle increases with increasing distance, and reaches the maximum immediately before the outer circumference.

In the diffuser 10 of this embodiment, a plurality of plate members 16 arranged radially in contact with one side on the central axis X in the diffuser body 12, that is, the splitter 1.
4 is provided, and the side closer to the inlet opening 12a is the diffuser body 12 around the central axis X of the plate member.
About 1/3 of the length of the central axis line X direction is cut out, and a space due to the cutout is formed in the central portion where the swirling flow is not relatively generated. For this reason, the contact area between the plate member and the fluid is reduced, the frictional resistance can be significantly reduced, and pressure recovery can be improved.

Furthermore, the diffuser 10 according to the present embodiment has an outer peripheral side of each diffuser 10 of the plate member 16 near the inlet opening 12a, that is, the diffuser main body 12
The inclined portion 16a is provided on the side in contact with the inner peripheral wall of the a.
The depth d (length in the direction of the central axis X) of the inclined portion 16a is increased in the radial direction from the central axis X of the diffuser body 12. Further, the inclined portion 16a is inclined in a direction in which the swirl flow F included in the flow flowing into the diffuser 10 is received and converted into the direction of the central axis X.
This is to suppress the swirling flow component and the friction loss.

The splitter 14 of FIG. 1 is formed in a cross shape as an example so as to divide the inside of the diffuser body 12 into four, but depending on the size of the diffuser, it may be divided into six, eight, or the like. It may have a shape. Further, the position of the inclined portion 16a is only near the inlet opening 12a, but it may be extended in the fluid flow direction. Furthermore, regarding the shape of the inclined portion 16a, in the representative example, a bending plane is taken into consideration in consideration of bending, but even a curved curved surface having a changed curvature as shown in FIG. Good.

As described above, the plate member 16 of the splitter 14
By providing the inclined portion 16a on the outer peripheral side of the entrance portion of
When a flow including the swirl flow F flows into the diffuser 10 (for example, when there is a rotary machine such as a compressor on the upstream side of the inlet opening 12a), the swirl flow F is gradually changed to a flow in the central axis X direction. Thus, the collision loss of the swirling flow F on the plate member 16 can be reduced, and the performance of the diffuser 10 such as pressure recovery can be improved.

Next, a diffuser according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a vertical sectional view of the diffuser according to the present embodiment, and FIG.
Is a side view taken along the line B-B in FIG. 3, and FIG.
It is another example of the side view taken along the arrow B.

In the diffuser of this embodiment, the variable inclined portion 26a of the plate member 26 of the splitter 24 is the plate member 16 of the splitter 14 in the first embodiment described above.
Unlike the inclined portion 16a of FIG. 3, the diffuser body 12 has a variable inclination structure pivotally supported by each plate member 26 via a support shaft 26b, and the diffuser body 12 is the same as that of the first embodiment except for the splitter 24. is there.

In the present embodiment, the support shaft 26b is shown in FIG.
It is provided so as to be orthogonal to the diffuser body 12 as shown in FIG. This is to minimize the gap with the inner surface of the diffuser body 12 when the variable tilting portion 26a is tilted.

A pin 26c is provided on the variable inclined portion 26a so as to project to the outside through an arcuate groove 21 opened in the diffuser body 12, and a screw portion provided at the tip of the pin 26c. It is fixed by a fixing screw 26e that is screwed.

As shown in FIG. 4 (a), the groove 21 is formed by the support shaft 2
6b is formed in an arc shape, the pin 26c penetrates through the groove 21, the variable inclined portion 26a can freely tilt as shown by an arrow Y, and the fixing screw 26e is used at a position keeping a desired angle. Fixed. It should be noted that FIG. 4B shows a case where the variable inclined portion 26a 'is formed as a curved curved surface.

In the present embodiment, when a fluid flow including the swirling flow F flows into the diffuser body 12 as in the case shown in FIGS. 1 and 2 (for example, a compressor or the like is provided upstream of the inlet opening 12a). Swirl flow F)
The tilt angle of the variable tilt portion 26a can be variably set according to the size and strength of the variable tilt portion 26a and can be fixed with the fixing screw 26e.

Further, even when the angle of the swirling flow F changes, the variable slanting structure of the variable slanting portion 26a welcomes the swirling flow F at a more optimal angle with respect to the inflow angle of the wide swirling flow a and gradually moves in the direction of the central axis X. Can be changed to
The collision loss of the swirling flow F on the plate member 26 of the splitter 24 can be minimized, and the performance of the diffuser 20 such as pressure recovery can be improved.

In particular, as shown in FIG. 4 (b), the one having the curved variable inclined portion 26a 'can direct the inclined portion tip in the swirling flow direction with a small inclination angle, and in addition, the variable inclined portion 26a. It is possible to smoothly convert the flow after flowing into the'in the direction of the central axis X, and to recover pressure more effectively.

A diffuser according to a third embodiment of the present invention will be described with reference to FIGS. 5 and 6. 5 is a perspective view of the diffuser of the present embodiment, and FIG. 6 is CC in FIG.
It is a top view by the arrow.

As shown in FIGS. 5 and 6, the diffuser 20 'of the present embodiment is different from the second embodiment described above in that the variable inclined portion 26a, the support shaft 26b, the pin 26c, the groove 21, and the notch 17 are provided. Basically the same, but each pin 26c
Is a connecting ring 29 arranged on the outer periphery of the diffuser body 12.
The connection ring 29 is tilted and controlled by the control rod 28 driven in the arrow Z direction in FIGS. 5 and 6 by a controller (not shown).

Further, the variable inclined portion 26a has a depth (central axis) similar to that of the inclined portion 16a of the first embodiment shown in FIG. 1 for suppressing the swirling flow component and the friction loss. The length (in the X direction) is formed so as to increase from the central axis X of the diffuser body 12 in the radial direction, and the support shaft 26b is attached in a direction aligned with it. Therefore, the variable sloping portion 26a provides a clearance with the inner surface of the diffuser body 12, but since the tilting angle range of the variable sloping portion 26a is not large, the clearance does not have to be large, and leakage from the clearance does not occur. Few.

In this embodiment, the diffuser 2
When the fluid flow including the swirling flow F flows into 0 ′ (for example, when there is a rotary machine such as a compressor on the upstream side of the inlet opening 12a), the connecting ring 29 is rotationally driven via the control rod 28. By doing so, it is possible to tilt and drive all the variable tilt portions 26a at the same time.

Further, even if the angle or size of the swirling flow F changes during operation, it is possible to perform simultaneous adjustment and setting of the variable inclined portion 26a so that the swirling flow F can be received at an optimum angle, and the swirling flow F can be mainly adjusted. The flow can be gradually changed in the direction of the axis X, the collision loss of the swirling flow F on the plate member 26 can be minimized, and the performance of the diffuser can be improved.

Therefore, since the inclination angle of the swirling flow F of the fluid a that has flowed into the variable slanting portion 26a can be adjusted all at once, the efficiency can be improved with respect to the change of the inflowing angle of the swirling flow a having a wide inflowing angle. It can respond well and enables effective pressure recovery.

In the present embodiment as well, as the variable inclined portion, the variable inclined portion 26a 'forming the curved curved surface as shown in FIG. 4B is adopted to further improve the efficiency. It goes without saying that you can also do it.

The embodiment of the present invention has been described above.
Needless to say, the present invention is not limited to the above-described embodiment, and various modifications may be made to the specific structure within the scope of the present invention.

[0053]

(1) According to the first aspect of the invention, the diffuser is circumferentially provided in the diffuser main body which is a hollow member that expands along the central axis line from the inlet opening to the outlet opening. A splitter including a plurality of plate members divided into a plurality of flow paths is provided, and the plate member is configured so as to cut out a portion around the central axis line adjacent to the inlet opening, so that each of the divided members is divided. The divergence angle in the flow path is smaller than that without the splitter, flow separation is suppressed, and in addition to being able to increase the reduction ratio of the diffuser without degrading performance,
Since the notch is provided around the central axis line where the swirling flow is small, the contact area between the plate member and the fluid is reduced, the frictional resistance can be significantly reduced, and the pressure recovery can be improved.

(2) According to the invention of claim 2, claim 1
2. The diffuser according to claim 1, wherein an inclined portion forming a refraction plane is formed in a portion adjacent to the inlet opening of the plate member and in contact with the inner peripheral surface of the diffuser body. In addition to the effect of the invention described above, the inclined portion of the plate member adjacent to the inlet opening enables more effective pressure recovery with respect to the swirling flow of the fluid flowing into the diffuser.

(3) According to the invention of claim 3, claim 2
The diffuser according to claim 2, wherein the inclined portion is formed to have a curved curved surface.
In addition to the effect of the invention described above, since the slanted portion has a curved curved surface, the tip of the slanted portion can be directed in the swirling direction with a smaller slanting angle, and the swirling flow of the fluid flowing into the slanting portion can be directed in the central axis direction. It can be converted smoothly, and more effective pressure recovery is possible.

(4) According to the invention of claim 4, claim 2
Alternatively, in the diffuser according to claim 3, since the inclined portion is pivotally supported by the plate member so as to be tiltable, and the fixing means of the inclined portion is provided between the inclined member and the diffuser body. In addition to the effect of the invention of claim 2 or claim 3, since the inclination angle can be adjusted according to the size of the swirling flow of the inflowing fluid in the inclined portion, a pressure more effective for the swirling flow having a wide inflow angle. Recovery is possible.

(5) According to the invention of claim 5, claim 2
Alternatively, in the diffuser according to claim 3, the inclined portions are pivotally supported by the plate member so as to be capable of inclining, and are locked to each other by a link mechanism so that all the inclined portions are simultaneously driven to be inclined. Therefore, claim 2
In addition to the effect of the invention of claim 3, the inclination angle can be adjusted all at once in accordance with the size of the swirling flow of the fluid that has flowed into the slanted portion, so that the inflow angle of the swirling flow with a wide inflow angle can be changed. Efficient response and effective pressure recovery are possible.

[Brief description of drawings]

FIG. 1 is a perspective view of a diffuser according to a first exemplary embodiment of the present invention.

FIG. 2 is a plan view taken along the line AA in FIG.

FIG. 3 is a vertical sectional view of a diffuser according to a second embodiment of the present invention.

FIG. 4A is a side view taken along the line BB in FIG.
3B is another example of the side view taken along the line BB in FIG.

FIG. 5 is a perspective view of a diffuser according to a third embodiment of the present invention.

6 is a plan view taken along the line CC in FIG.

FIG. 7 is a graph showing a distribution of a general swirling flow magnitude in a radial direction in a diffuser.

FIG. 8 is a perspective view of an example of a conventional diffuser.

FIG. 9 is a perspective view of another example of a conventional diffuser.

[Explanation of symbols]

10 diffuser 12 Diffuser body 12a entrance opening 12b outlet opening 14 Splitter 16 Plate member 16a inclined part 17 notches 20, 20 'diffuser 21 groove 24 splitter 26 Plate members 26a, 26a 'variable tilting portion 26b spindle 26c pin 26e Fixing screw 28 Control rod 29 connecting rings

Claims (5)

[Claims] 1. A splitter composed of a plurality of plate members circumferentially divided into a plurality of flow passages is provided in a diffuser body composed of a hollow member that expands along an axis from an inlet opening toward an outlet opening. The diffuser is characterized in that the plate member is formed by cutting out a portion around the central axis adjacent to the inlet opening. 2. The diffuser according to claim 1, wherein an inclined portion is formed in a portion adjacent to the inlet opening of the plate member and in contact with an inner peripheral surface of the diffuser body. Diffuser. 3. The diffuser according to claim 2, wherein the inclined portion is formed to have a curved curved surface. 4. The diffuser according to claim 2, wherein the inclined portion is pivotally supported by the plate member so as to be tiltable, and fixing means for the inclined portion is provided between the inclined portion and the diffuser body. A diffuser characterized by that. 5. The diffuser according to claim 2 or 3, wherein the inclined portions are pivotally supported by the plate member so as to be capable of inclining and are locked to each other by a link mechanism, and all the inclined portions are simultaneously driven to be inclined. A diffuser characterized by being configured as described above.