JP5535562B2 - Discharge scroll and turbo machine - Google Patents

Description

  The present invention relates to a discharge scroll connected to a discharge passage of a turbomachine and a turbomachine including the same.

  In turbomachines such as compressors, turbines, and pumps, a discharge scroll formed in an annular shape is attached to a discharge passage of the working fluid, and the working fluid is concentrated inside the discharge scroll and swirled along the circumferential direction. And discharged from a discharge pipe extending toward the radially outer peripheral side (see, for example, Patent Documents 1 and 2).

  FIG. 8 shows a conventional view of a discharge scroll attached to a discharge flow path of an axial compressor. As shown in FIG. 8, in the axial flow compressor, a diffuser 100 having a substantially annular cross section as a discharge flow path is provided at the end of the flow path where the moving blades and the stationary blades are disposed. FIG. 8 shows only one side of the center axis (rotation axis) L and omits the other side. The diffuser 100 is formed so that the cross-sectional area gradually increases, thereby converting the dynamic pressure of the fluid F discharged from the flow path into a static pressure. At this time, the diffuser 100 is based on analysis by CFD or the like and empirical rules. The curvature in the direction of the road extension, the rate of change of the cross-sectional area, the area ratio between the entrance and the exit, etc. are set. The diffuser 100 is extended along the axial direction along with the flow path on the inlet 100a side, and is curved so as to go to the radially outer periphery side toward the outlet 100b side, and is formed in a trumpet shape as a whole. Yes. The discharge scroll 101 is annularly arranged on the radially outer peripheral side of the outlet 100 b so as to be connected to the outlet opening 100 c of the diffuser 100, and the fluid F flows from the diffuser 100. The fluid F that has flowed into the discharge scroll 101 swirls along the inner wall surface 101a of the discharge scroll 101 in the cross section including the central axis L, and is mixed with the fluid F flowing in at different positions in the circumferential direction and is circumferentially mixed. Will flow along.

Japanese Utility Model Publication No. 7-8597 JP 2005-155393 A

  However, in the structure of the discharge scroll 101 as shown in Patent Documents 1 and 2 and FIG. 8, the fluid F swirling along the inner wall surface 101a of the discharge scroll 101 in the cross section including the central axis L, and the newly flowing fluid There is a problem that pressure loss occurs due to collision and mixing of F with the inlet portion 101b.

  The present invention has been made in view of the above-described circumstances, and collects and discharges inflowed fluid while reducing pressure loss due to collision / mixing between the fluid swirling inside and the inflowing fluid. It is possible to provide a discharge scroll that can be used.

The present invention employs the following means in order to solve the above problems.
The present invention is a discharge scroll that is connected to a discharge passage of a turbomachine and into which a fluid discharged from the discharge passage flows, a scroll body that forms a space having a substantially annular cross section, the discharge passage, And a connection portion for connecting the scroll body and forcibly decelerating the fluid discharged from the discharge flow path to flow into the scroll body, and the connection portion is an inlet connected to the discharge flow path. And a wall part that decelerates the fluid that flows through the enlargement of the flow path area and is connected to the outlet part from the inlet part. characterized Rukoto is peeled off the fluid along.

According to this configuration, the fluid that has flowed into the connection portion from the discharge flow path is forcibly decelerated by the connection portion. For this reason, it will flow into the scroll body in a sufficiently decelerated state, and the fluid flowing in and the fluid swirling the scroll body will collide, mix and collect in the scroll body. Reduction can be achieved.
Further, the fluid flowing from the inlet portion to the outlet portion of the connecting portion can be forcibly and effectively decelerated due to the expansion of the flow area.
Further, in the connecting portion, the fluid flowing from the inlet portion to the outlet portion can be forcibly and effectively decelerated by peeling along the wall portion.

Further, in the discharge scroll, the connection portion is provided over the entire circumference in the inlet portion of the wall portion or in the vicinity of the inlet portion, and has a corner portion for separating the fluid, and the outlet portion is more than the corner portion. It is preferable that the fluid is peeled off at the part side.

According to this configuration, the fluid can be forcibly and effectively decelerated at the connecting portion by separating the fluid on the outlet portion side of the inlet portion of the wall portion or the corner portion provided in the vicinity of the inlet portion. In addition, the corners can surely prevent the fluid from peeling up to the discharge channel side.

A discharge scroll that is connected to a discharge flow path of a turbomachine and into which a fluid discharged from the discharge flow path flows, a scroll body that forms a substantially annular space in cross section, and the discharge flow path and the scroll body. And a connection part for forcibly decelerating the fluid discharged from the discharge flow path and flowing into the scroll body, and the connection part has a fluid peeling part for forcibly peeling the fluid. It is preferable.

  According to this configuration, the fluid flowing through the connection portion is effectively decelerated by being forcibly separated by the fluid separation portion.

In the discharge scroll, the connection portion includes an inlet portion connected to the discharge flow path, and an outlet portion in which the flow area of the fluid is larger than that of the inlet portion. It is preferable to decelerate the fluid flowing through enlargement.

In the discharge scroll described above, it is preferable that the connecting portion separates the fluid along a wall portion connected from the inlet portion to the outlet portion.

Further, in the discharge scroll, the connection portion is provided over the entire circumference in the inlet portion of the wall portion or in the vicinity of the inlet portion, and has a corner portion for separating the fluid, and the outlet portion is more than the corner portion. It is preferable that the fluid is peeled off at the part side.

  In addition, a turbo machine according to the present invention includes the above-described discharge scroll and a discharge flow path that discharges the fluid to the discharge scroll.

  According to this configuration, it is possible to reduce the pressure loss due to the collision / mixing in the discharge scroll, thereby effectively reducing the loss as a whole.

According to the discharge scroll of the present invention, the fluid swirling inside and the inflowing fluid collide and mix to collect pressure in the inflowing fluid while reducing pressure loss by gathering in the discharge scroll. Can be made.
Further, according to the turbo machine of the present invention, the used fluid can be discharged from the discharge channel via the discharge scroll while reducing the loss as a whole.

It is a half sectional view of the axial flow compressor of a 1st embodiment of the present invention. It is sectional drawing which shows the detail of the discharge scroll of the 1st Embodiment of this invention. It is sectional drawing which shows the detail of the discharge scroll of the 1st modification of the 1st Embodiment of this invention. It is sectional drawing which shows the detail of the discharge | emission scroll of the 2nd modification of the 1st Embodiment of this invention. It is sectional drawing which shows the detail of the discharge | emission scroll of the 3rd modification of the 1st Embodiment of this invention. It is sectional drawing which shows the detail of the discharge scroll of the 4th modification of the 1st Embodiment of this invention. It is sectional drawing which shows the detail of the discharge scroll of the 2nd Embodiment of this invention. It is sectional drawing which shows the conventional discharge scroll.

(First embodiment)
A first embodiment according to the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 shows an axial compressor 1 as an example of a turbo machine. As shown in FIG. 1, the axial flow compressor 1 includes a rotor 2, a flow path 1 a having a substantially annular cross section that is disposed on the outer periphery of the rotor 2 and through which air A serving as a working fluid flows between the rotor 2. A substantially cylindrical casing 3, a stationary blade 4 and a moving blade 5 disposed in the flow path 1a, a suction scroll 6 and a discharge scroll 10 for supplying and discharging air A to the flow path 1a, and a suction scroll 6 and a suction flow path 7 and a discharge flow path 8 that connect the discharge scroll 10 and the flow path 1a.

  The stationary blade 4 is attached to the inner peripheral surface of the casing 3 and is provided on the radially inner peripheral side toward the rotor 2. Further, the moving blade 5 is attached to the rotor 2 and is provided so as to protrude toward the casing 3 on the outer peripheral side in the radial direction. A plurality of the stationary blades 4 and the moving blades 5 are provided radially, and a plurality of stages are alternately provided along the axial direction X.

  The suction scroll 6 is provided on one side in the axial direction X of the casing 3, and is connected to the flow path 1 a by a suction flow path 7. The suction scroll 6 has a space formed in a substantially annular shape, and circulates air A flowing in from a suction port (not shown) along the circumferential direction Y, and a flow formed in a substantially annular cross section via the suction flow path 7. Air A is supplied over the entire path 1a.

  As shown in FIG. 2, the discharge flow path 8 is provided on the other side in the axial direction X of the casing 3, and without causing separation of the compressed air A that circulates as the flow cross section gradually increases. It is configured as a diffuser that decelerates. In addition, the discharge flow path 8 constituting the diffuser extends along the axial direction X together with the flow path 1a on the inlet 8a side, and is curvedly formed so as to go to the outer peripheral side in the radial direction toward the outlet 8b side. The whole is formed in a trumpet shape. The discharge scroll 10 is annularly arranged on the radially outer peripheral side of the outlet 8b so as to be connected to the opening of the outlet 8b of the discharge channel 8.

  The discharge scroll 10 connects the scroll main body 11 forming a space having a substantially annular cross section, the discharge flow path 8 and the scroll main body 11, and forcibly decelerates the air A discharged from the discharge flow path 8 to scroll the scroll main body. 11 and a connection portion 12 that flows into the device 11. In the connection part 12, the outlet part 12 b has a larger flow area in the inlet part 12 a connected to the discharge flow path 8 and the outlet part 12 b connected to the scroll body 11. Moreover, in this connection part, the wall part 12c which connects the entrance part 12a and the exit part 12b is formed in linear form in the cross section containing the central axis L in this embodiment, and the connection part 12 is the whole. As shown, a substantially trapezoidal cross section is formed, and a corner 13 is formed between the inlet 12a and the discharge channel 8. Here, the increase amount of the channel area per unit length along the flow direction of the air A in the connection portion 12, that is, the increase rate of the channel area is set larger than the increase rate of the channel area in the discharge channel 8. Has been. Furthermore, in the connection part 12, the increase rate of a flow path area is set so that the air A which distribute | circulates along the wall part 12c may be peeled by the rapid increase in flow path area from the inlet part 12a to the outlet part 12b. Has been.

  In addition, the scroll main body 11 is configured so that the inflow air 14 is connected to the outer peripheral side in the radial direction of the outlet portion 12b of the connection portion 12 and the air A that flows in the circumferential direction in the space extending from the inflow portion 14 adjacent to the axial direction X. And a main body portion 15 that circulates as a swirl flow along Y. As shown in FIG. 2, the inner wall surface 11 a constituting the scroll main body 11 is a smooth curve between the inflow portion 14 and the main body portion 15 in a cross-sectional view including the central axis L. Further, the main body portion 15 extends toward the radially inner side from the inflow portion 14, and the wall A flows directly from the connection portion 12 to the main body portion 15 between the wall portion 15 and the connection portion 12. It is configured as an inflow restricting portion 16 that restricts

Next, the operation of the discharge scroll 10 of this embodiment will be described.
As shown in FIG. 2, the air A flowing into the discharge scroll 10 from the discharge flow path 8 first flows through the connection portion 12. The air A that has flowed into the connecting portion 12 is forcibly decelerated because the connecting portion 12 is formed so that the flow passage area increases from the inlet portion 12a to the outlet portion 12b. Moreover, in this embodiment, peeling A1 arises in the flow of the air A along the wall part 12c by expansion of the flow-path area from the inlet part 12a to the outlet part 12b abruptly changing, and more effectively by this. It can be decelerated.

  Then, the air A2 flowing through the connection portion 12 and flowing into the inflow portion 14 in the scroll main body 11 in this manner further turns in the main body portion 15 along the inner wall surface 11a in the cross section including the central axis L. It will be. Then, the air A3 swirling in the main body portion 15 flows toward the outer peripheral side in the radial direction along the inflow restricting portion 16 and collides with and mixes with the air A2 newly flowing into the main body portion 15 from the inflow portion 14. It will be. However, as described above, the air A2 flowing from the inflow portion 14 to the main body portion 15 is sufficiently decelerated at the connection portion 12, and therefore collides and is mixed and gathered in the scroll main body 11. Reduction of pressure loss can be achieved.

  Here, as described above, the separation A1 is caused in the connection portion 12 to cause a pressure loss, but the collision in the scroll body 11 accompanying the deceleration at the connection portion 12 is mixed and gathered. The pressure loss due to this can be greatly reduced, so that the pressure loss can be reduced as a whole. For this reason, a more efficient scroll can be implement | achieved by connecting the discharge scroll 10 with respect to the discharge flow path 8 which is a diffuser designed not to generate | occur | produce peeling etc. inside efficiently. Further, as described above, peeling A1 occurs at the wall portion 12c in the connecting portion 12. However, since the corner portion 13 is formed at the inlet portion 12a, the peeling A1 is formed on the outlet portion 12b side from the corner portion 13 as a starting point. As a result, it is possible to prevent the separation A1 from occurring up to the upstream discharge channel 8. The corner portion is not limited to the one formed by the inner wall surfaces intersecting as described above, and a protrusion is formed over the entire circumference in the vicinity of the inlet portion 12a or the inlet portion 12a. The corner portion may be formed by.

  FIG. 3 shows a first modification of the present embodiment. As shown in FIG. 3, in the present modification, the discharge flow path 20 is formed along the axial direction X as a whole, and the connection portion 22 of the discharge scroll 21 corresponds to the discharge flow path 20 in the axial direction X. It is formed along and connected to the discharge flow path 20. Further, in the discharge scroll 21, the scroll main body 23 has the inflow portion 14 connected to the connection portion 22 in the axial direction X, and the main body portion 15 extends to the radially outer peripheral side of the inflow portion 14. Thus, even when the discharge flow path 20 and the discharge scroll 21 are connected along the axial direction X, the pressure loss due to the collision in the scroll main body 23, mixing and gathering by providing the same configuration. Can be effectively reduced.

  FIG. 4 shows a second modification of the present embodiment. As shown in FIG. 4, in the discharge casing 30 of the present modification, the wall portion 12 c is formed in a step shape having a recess 12 d in a cross-sectional view including the central axis L, and the recess 12 d is a fluid peeling portion. As described above, the air A along the wall portion 12c can be forcibly separated. Then, the air A that flows through the connecting portion 12 is effectively decelerated by causing the air A along the wall portion 12c to be forcibly generated by the recess 12d, so that the collision and mixing in the scroll main body 11 are performed. The pressure loss due to the assembly can be further reduced.

  FIG. 5 shows a third modification of the present embodiment. As shown in FIG. 5, in the exhaust scroll 40 of this modification, the wall part 41a of the connection part 41 is formed in concave shape by the one side of the axial direction X. As shown in FIG. Moreover, in this modification, in the scroll main body 42, the main-body part 43 is formed so that it may spread in the radial direction outer peripheral side rather than the connection part 41, and it has a structure without the inflow control part 16 shown in FIG. As described above, in the connection portion 41 of this modification, the flow channel area is further increased in the vicinity of the inlet portion 12a as compared with the connection portion 12 shown in FIG. Separation A5 can be generated in the air A along the wall 41a. And since the air A which distribute | circulates the connection part 41 can be effectively decelerated by producing peeling A5 in this way, the air A3 which turns in the scroll main body 42 without the inflow control part 16 is provided. Even if it is the structure which flows toward the inflow part 14, the pressure loss by colliding, mixing, and gathering can be reduced. The wall 41a formed in a concave shape may be on the other side in the axial direction X or on both sides.

  FIG. 6 shows a fourth modification of the present embodiment. As shown in FIG. 6, in the exhaust scroll 50 of the present modified example, in the inside of the connection portion 12, as a fluid separation portion, an intermediate portion having a substantially triangular cross section with the inlet portion 12 a side as a vertex 51 a and the outlet portion 12 b side as a bottom side. A plurality of walls 51 are supported by the columns 52 and formed. And the air A which flowed in from the inlet part 12a distribute | circulates between the intermediate walls 51, and between the intermediate wall 51 and the wall part 12c, and peeling A6 arises from the corner | angular 51b of the bottom side of the intermediate wall 51 as a base point. It becomes. For this reason, the air A flowing through the connecting portion 12 is further effectively decelerated by the separation A6 in the intermediate wall 51, and thereby, the collision in the scroll body 11 is more effectively collected and mixed. Therefore, the pressure loss can be reduced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 7 shows a second embodiment of the present invention. In this embodiment, the same members as those used in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 7, in the connection portion 62 of the discharge scroll 61, the portion on the inner side of the flow path does not have a smooth curved shape, but forms a corner 61 a. In the present embodiment, a corner 61 b is further formed at the connection portion between the main body portion 15 and the connection portion 62 even at a position inside the flow path of the connection portion 62.

  In the discharge scroll 61 of this embodiment, when the air A flowing through the discharge flow channel 60 flows into the connecting portion 62, a corner 61a is formed at a position inside the flow channel. Functions as a forced separation portion, and separation A7 occurs in the flow of air A. Similarly, when the air A3 flowing into the scroll main body 63 from the connecting portion 62 and turning around the main body portion 15 flows along the inflow restricting portion 16 toward the radially outer peripheral side, the corner 61b functions as a forced peeling portion. Then, separation A8 occurs in the flow of air A3. For this reason, the air A that flows through the connecting portion 62 and the air A3 that flows through the main body portion 15 are disturbed by the separations A7 and A8, causing a pressure loss and being rapidly decelerated. For this reason, even if the air A which circulates through the connection part 62 and the air A3 which circulates through the main body part 15 collide and mix, it is possible to reduce the pressure loss, thereby reducing the pressure loss as a whole. Can do. Moreover, since the flow directions of the air A and the air A3 flowing into the scroll main body 63 from the connection portion 62 substantially coincide with each other, it is possible to suppress the occurrence of pressure loss when mixing.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

  In addition, although the exhaust scroll shown by each said embodiment and each modification was demonstrated as what is mounted in an axial flow compressor, it is not restricted to this, It is applicable also to a centrifugal compressor. Furthermore, the present invention is not limited to the compressor, and can be applied as a structure for discharging the working fluid in various turbo machines such as a gas turbine, a steam turbine, and a submersible pump.

1 Axial flow compressor (turbo machine)
8, 20, 60 Discharge flow path
10, 21, 30, 40, 50, 61 Discharge scroll 11, 42, 63 Scroll body 12, 22, 41, 62 Connection part 12a Inlet part 12b Outlet part 12c Wall part 12d Indentation (forced peeling part)
13 corner 51b corner (forced peeling part)
61a, 61b corner (forced peeling part)
A Air (fluid)

Claims (7)

A discharge scroll connected to a discharge path of a turbomachine and into which a fluid discharged from the discharge path flows;
A scroll body forming a substantially annular space in cross section;
Connecting the discharge flow path and the scroll body, and comprising a connection portion for forcibly decelerating the fluid discharged from the discharge flow path and flowing into the scroll body ,
The connection part has an inlet part connected to the discharge flow path, and an outlet part whose flow area of the fluid is larger than that of the inlet part. is decelerated, the discharge scroll, wherein Rukoto is peeled off the fluid along the wall leading to the outlet from the inlet. The discharge scroll according to claim 1,
The connecting portion is provided over the entire circumference in the inlet portion of the wall portion or in the vicinity of the inlet portion, and has a corner portion for peeling the fluid, and the fluid is peeled on the outlet portion side of the corner portion. Discharge scroll characterized by that. A discharge scroll connected to a discharge path of a turbomachine and into which a fluid discharged from the discharge path flows;
A scroll body forming a substantially annular space in cross section;
Connecting the discharge flow path and the scroll body, and comprising a connection portion for forcibly decelerating the fluid discharged from the discharge flow path and flowing into the scroll body,
The discharge scroll according to claim 1, wherein the connection portion includes a fluid peeling portion that forcibly peels the fluid . The discharge scroll according to claim 3,
The connection part has an inlet part connected to the discharge flow path, and an outlet part whose flow area of the fluid is larger than that of the inlet part. Discharge scroll characterized by decelerating. The discharge scroll according to claim 4,
The discharge scroll according to claim 1, wherein the connecting portion separates the fluid along a wall portion connected from the inlet portion to the outlet portion. The discharge scroll according to claim 5,
The connecting portion is provided over the entire circumference in the inlet portion of the wall portion or in the vicinity of the inlet portion, and has a corner portion for peeling the fluid, and the fluid is peeled on the outlet portion side of the corner portion. Discharge scroll characterized by that. The discharge scroll according to any one of claims 1 to 6 ,
A turbomachine comprising: a discharge flow path for discharging the fluid to the discharge scroll.

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