JP2007303324A - Turbine exhaust system, and its modifying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbine exhaust system, which can efficiently improve the pressure recovering performance of an existing turbine exhaust system, and further to provide its modifying method. <P>SOLUTION: The turbine exhaust system comprises an inner casing 3 for surrounding a turbine rotor 1 therein, a flow guide 5 provided so as to continue to the exit annular band 4 of the final stage rotor blade of a turbine rotor 1, a bearing cone 6 provided so as to continue to the inner peripheral portion of the exit annular band 4 of the final stage rotor blade, an outer casing 8 for forming an exhaust chamber 7 to be connected to a condenser together with the bearing cone 6 and the inner casing 3, an annular diffuser passage 9 to be formed by the flow guide 5 and the bearing cone 6, and a passage adjusting member which is a plate shape member for reducing an effective passage cross sectional area of the diffuser passage 9, and is arranged on the bearing cone 6 so as to face to the diffuser passage 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a turbine exhaust device that guides exhaust gas after driving a turbine rotor to a condenser and a method for remodeling the same.

  A steam turbine facility having a condenser discharges steam that has worked inside the turbine to an exhaust device, recovers the pressure in the exhaust device, and then supplies the steam to the condenser. When the pressure recovery width by the exhaust device is large, the turbine outlet pressure is lowered, the work of the turbine is increased, and the energy obtained by driving the turbine is increased. Thus, the pressure recovery performance of the steam by the exhaust device greatly affects the turbine plant performance.

  The exhaust system as described above is provided continuously with the flow guide provided continuously with the outer periphery of the final stage rotor blade outlet ring of the turbine rotor and with the inner periphery of the final stage rotor blade outlet ring. There is an annular flow path formed from a bearing cone or the like, which has a diffuser flow path whose cross-sectional area gradually increases toward the downstream side. Some exhaust devices of this type have optimized the shape of the diffuser flow path by devising the shape of the member itself forming the diffuser flow path (for example, the shape of the flow guide or the shape of the bearing cone) (patented) The pressure recovery performance of the exhaust device is improved by reducing the pressure loss that occurs when the exhaust passes through the diffuser flow path.

JP 2005-233154 A

  By the way, when applying the above technique to an existing exhaust system, it is conceivable to optimize the shape of the diffuser flow path by exchanging the flow guide and / or the bearing cone. However, the replacement work in that case is inevitably large and costly in terms of the amount of materials used, workability, workability, and the like. Needless to say, when the entire exhaust device is replaced, the operation is much larger than when only the members are replaced.

  An object of the present invention is to provide a turbine exhaust apparatus and a method for remodeling the turbine exhaust apparatus that can efficiently improve the pressure recovery performance of an existing turbine exhaust apparatus.

  (1) In order to achieve the above object, the present invention provides a turbine exhaust device that guides exhaust gas after driving a turbine rotor to a condenser, an exhaust indoor casing that contains the turbine rotor, and the turbine rotor A flow guide provided continuously on the outer periphery of the final stage rotor blade outlet ring, a bearing cone provided continuously on the inner periphery of the last stage blade outlet ring, and the bearing cone and the An exhaust chamber outer casing that forms an exhaust chamber connected to the condenser together with an exhaust chamber inner casing, an annular flow path formed by the flow guide and the bearing cone, and driving the turbine rotor to The diffuser flow path for blowing the exhaust gas that has passed through the final stage rotor blade outlet annulus to the exhaust chamber and the effective flow cross-sectional area of the diffuser flow path are reduced. A plate-like member of order, it is assumed and a flow path adjusting member provided on the bearing cone so as to face the diffuser passage.

  (2) In order to achieve the above object, the present invention provides a turbine exhaust device that guides exhaust gas after driving a turbine rotor to a condenser, an exhaust indoor casing that contains the turbine rotor, and the turbine rotor A flow guide provided continuously on the outer periphery of the final stage rotor blade outlet ring, a bearing cone provided continuously on the inner periphery of the last stage blade outlet ring, and the bearing cone and the An exhaust chamber outer casing that forms an exhaust chamber connected to the condenser together with an exhaust chamber inner casing, and the final stage rotor blade outlet ring among the flow guide, the bearing cone, and the inner wall surface of the exhaust chamber outer casing An annular flow path formed by an inner side surface facing the belt, wherein the exhaust gas that has driven the turbine rotor and passed through the final stage blade outlet ring belt is exhausted. A diffuser flow path for blowing into the chamber, and a plate-like member for reducing the effective flow cross-sectional area of the diffuser flow path, and a flow path adjusting member provided on the inner side surface so as to face the diffuser flow path; Shall be provided.

  (3) In the above (1) or (2), preferably, the flow path adjustment member is configured such that an effective flow cross-sectional area of the diffuser flow path is gradually increased in proportion to a distance from the final stage rotor blade outlet annulus. It is assumed that the bearing cone is provided so as to expand.

  (4) In the above (1) or (2), preferably, the flow path adjustment member is configured to change the diffuser flow path based on a result of measuring a change in flow path cross-sectional area in the exhaust flow direction of the diffuser flow path. It is assumed that the bearing cone is provided so that its effective flow cross-sectional area gradually increases in proportion to the distance from the final stage rotor blade outlet annulus.

  (5) In any one of the above (1) to (4), preferably, the flow path adjustment member is attached to the bearing cone radially about the rotation axis of the turbine rotor.

  (6) In any one of the above (1) to (5), preferably, the flow path adjusting member is attached to the bearing cone symmetrically.

  (7) In order to achieve the above object, the present invention provides a turbine exhaust device remodeling method that guides exhaust gas after driving a turbine rotor to a condenser, and an exhaust indoor casing that contains the turbine rotor; A flow guide provided continuously on the outer peripheral portion of the last stage rotor blade outlet ring of the turbine rotor, a bearing cone provided continuously on the inner periphery of the last stage rotor blade outlet ring, and this bearing An exhaust chamber outer casing forming an exhaust chamber connected to the condenser together with a cone and the exhaust chamber inner casing, an annular flow path formed by the flow guide and the bearing cone, and driving the turbine rotor A diffuser flow path for blowing the exhaust gas that has passed through the final stage rotor blade outlet annulus to the exhaust chamber. The ring cone, and shall be additionally provided so as to face the flow path adjusting member is a plate-shaped member in the diffuser flow path reduces the effective Nagaredan area of the diffuser flow path.

  According to the present invention, the shape of the diffuser flow path can be optimized without replacing the entire existing turbine exhaust system or the members constituting the turbine exhaust system, so that the pressure recovery performance of the existing turbine exhaust system can be improved efficiently. it can.

  Embodiments of a turbine exhaust device of the present invention will be described below with reference to the drawings.

  FIG. 1 is a side sectional view schematically showing a basic structure of a turbine exhaust system according to an embodiment of the present invention, FIG. 2 is a sectional view taken along a line II-II in FIG. 1, and FIG. FIG. 4 is an enlarged side sectional view showing the vicinity of a turbine final stage in the turbine exhaust device of the embodiment in detail, and FIG. 4 is a perspective sectional view as seen from the direction of arrow IV in FIG.

  The illustrated turbine exhaust apparatus guides exhaust gas after driving the turbine rotor 1 to a condenser (not shown) provided below via an exhaust chamber outlet 2. This turbine exhaust device is continuously connected to the outer peripheral portion of an exhaust chamber inner casing (inner casing) 3 that encloses the turbine rotor 1, and a final stage rotor blade outlet annulus (exit annulus) 4 (described later) of the turbine rotor 1. Along with the provided flow guide 5, a bearing cone 6 provided continuously on the inner periphery of the outlet ring 4 and covering a bearing (not shown) of the turbine rotor 1, together with the bearing cone 6 and the exhaust chamber casing 3 An annular passage formed by an exhaust chamber outer casing (external casing) 8 forming an exhaust chamber 7 connected to the condenser, a flow guide 5 and a bearing cone 6, which drives the turbine rotor 1 and exits A diffuser flow path 9 for blowing exhaust gas that has passed through the annular zone 4 to the exhaust chamber 7, and a plate-like member for reducing an effective flow cross-sectional area (described later) of the diffuser flow path 9 , And a flow path adjusting member 40 provided on the bearing cone 6 so as to face the diffuser passage 9.

  The turbine rotor 1 has a plurality of moving blades (in FIG. 1 and FIG. 3, only the final stage moving blade 10 is shown) arranged in the circumferential direction of the turbine rotor 1. The rotor blades are driven by the steam passing therethrough and give the turbine rotor 1 an axial rotational force.

  The inner casing 3 has a diaphragm 11 (see FIG. 3) provided in an annular shape on the inner peripheral side, and encloses the turbine rotor 1. In FIG. 3, the diaphragm 11 is provided from the turbine rotor 1 to the outer side in the radial direction with an appropriate interval, and from the inner ring 13 to the outer side in the turbine rotor 1 in the radial direction with an appropriate interval. And an outer ring 14. A space between the inner ring 13 and the outer ring 14 serves as a steam flow passage 15 through which steam flows, and the stator blades (see FIG. 5) are disposed in the steam flow passage 15 so as to face the moving blades disposed in the turbine rotor 1. In FIG. 3, only the final stage stationary blade 16 is shown). A moving blade and a corresponding stationary blade are paired to constitute one turbine stage (the final stage moving blade 10 and the final stage stationary blade 16 constitute the final stage). A plurality of paragraphs are arranged at predetermined intervals along the axial direction of the turbine rotor 1. The final stage rotor blade annulus 4 is an annular opening formed by the tip diameter and the root diameter of the final stage rotor blade 10, and after the turbine rotor 1 is driven while passing through the steam flow passage 15. Exhaust gas (steam) flows into the diffuser flow path 9 through here.

  The bearing cone 6 is provided with one end in the axial direction continuous to the inner peripheral portion of the outlet annular zone 4 and the other end to the inner side surface 17 facing the outlet annular zone 4 of the inner wall surface of the outer casing 8. It is a weight-like member that extends and has a cross-sectional shape in the axial direction that gradually increases toward the inner side surface 17. A bearing (not shown) that supports the shaft of the turbine rotor 1 is provided inside the bearing cone 6.

  The flow guide 5 is provided such that one end in the axial direction is continuously provided on the outer periphery of the outlet ring 4 and the other end faces the exhaust chamber 7. It arrange | positions so that a part of 4 may be surrounded from outer periphery.

  The diffuser channel 9 is an annular channel formed by the bearing cone 6 and the flow guide 5, and has a shape in which the channel cross-sectional area gradually increases toward the downstream side in the exhaust flow direction. The diffuser flow path 9 drives the turbine rotor 1 to blow out the exhaust gas that has passed through the outlet ring zone 4 of the final stage moving blade 10 toward the condenser. The steam (exhaust gas) discharged from the exit annulus 4 is decelerated while passing through the diffuser passage 9 that gradually expands as described above, while the pressure is recovered by converting the energy of the deceleration to pressure. The When the pressure recovery width in the diffuser flow path 9 is improved, the turbine outlet pressure is reduced and the work of the turbine is increased, so that the energy obtained by driving the turbine is increased. Various methods for improving the pressure recovery performance of the exhaust system (exhaust chamber) have been studied in order to improve the turbine plant performance. Among them, it is known that optimizing the diffuser flow path 9 is particularly effective. It has been.

  Here, the flow path adjusting member 40 will be described in detail.

  In FIG. 4, the flow path adjustment member 40 is a plate-like member for reducing the effective flow cross-sectional area of the diffuser flow path 9, and the end face (attachment end face) attached to the bearing cone 6 is the attachment location. Is formed along the curved surface of the bearing cone 6, and the flow of the diffuser flow path 9 is as much as necessary to reduce the effective flow cross-sectional area of the end face facing the flow path 9 located on the opposite side of the mounting end face. It is shaped to protrude in the direction of the road center. Since the adjusting member 40 has a plate shape to the last, it does not actively reduce the cross-sectional area of the flow path as a geometric shape, but it effectively acts as an obstacle when exhaust passes, The cross-sectional area (effective flow path cross-sectional area) of the exhaust flow (steam flow) formed inside can be reduced. The adjusting member 40 is shaped and arranged based on the measurement result (described later) of the change in the flow passage cross-sectional area in the exhaust flow direction of the diffuser flow passage 9, and the effective flow cross-sectional area of the diffuser flow passage 9 is The bearing cone 6 is provided so as to gradually expand in proportion to the distance. For example, an appropriate number is attached in the circumferential direction of the bearing cone 6 by welding or the like. In FIG. 4, only three adjustment members 40 (40a, 40b, 40c) are shown in a simplified manner.

  Even if only one adjustment member 40 is attached, the effect of reducing the effective flow cross-sectional area is exhibited. Usually, however, the adjustment members 40a to 40c in FIG. A plurality of adjusting members 40 are attached in parallel. By mounting in parallel at an appropriate interval in this way, the effective flow cross-sectional area can be easily reduced as compared with the case where the bearing cone is replaced. This utilizes the viscous action of the exhaust flow as a fluid. When the mounting interval of the members 40 is adjusted appropriately, the exhaust flow does not easily flow into the gap. The same effect as that obtained by reducing the size can be easily obtained with only a few adjustment members 40. As described above, in the present embodiment, the effective flow cross-sectional area can be reduced without replacing the bearing cone 6 simply by adding the adjustment member 40 to the existing bearing cone 6. Remodeling to improve pressure recovery performance can be done easily.

  The adjustment member 40 is preferably attached to the bearing cone 6 radially with respect to the rotational axis of the turbine rotor 1 such that the plate surface follows the radial direction of the turbine rotor 1 like the adjustment members 40a to 40c. This is because the exhaust (steam) is discharged radially from the outlet ring zone 4 with respect to the rotational axis of the turbine rotor 1. When arranged in this way, the exhaust velocity component in the diffuser flow path 9. It is possible to suppress the occurrence of pressure loss due to the change.

  Further, the adjustment member 40 is preferably attached so that the arrangement and shape thereof are symmetrical with respect to the bearing cone 6 like the adjustment members 40b and 40c. This is because the diffuser flow path 9 is generally formed in line symmetry (left-right symmetry) with a vertical straight line passing through the rotational axis of the turbine rotor 1 as the axis of symmetry. Generation of turbulent flow in the path 7 can be suppressed. In FIG. 4, the adjusting member 40b and the adjusting member 40c are attached to the bearing cone 6 symmetrically and radially, respectively.

  In addition, when it is found from the analysis result of the flow of the exhaust flow or the like that a left-right asymmetric flow is generated in the diffuser flow path 9, the turbulent flow is not performed without the radial arrangement or the symmetrical arrangement as described above. If the adjusting member 40 is appropriately disposed so as to eliminate the turbulence, the effective flow sectional area can be adjusted while eliminating the turbulent flow.

  Next, a method for measuring a change in the cross-sectional area of the flow passage in the exhaust flow direction of the diffuser flow passage 9 and a method for specifying the attachment location of the flow passage adjustment member 40 will be described with reference to FIGS.

  Here, in order to facilitate understanding of the method of measuring the cross-sectional area of the flow path, the flow path shape of the diffuser flow path 9 is symmetric with respect to the circumferential direction of the rotor 1 around the rotation axis of the turbine rotor 1. It is assumed that the exhaust flow inside is the same, and in the diffuser flow passage 9A simplified by such assumption, a flow passage cross section orthogonal to the main flow (described later) of the exhaust flow is defined, and the change in the cross sectional area is measured. Shall.

  FIG. 5 is a cross-sectional view of the lower half side of the diffuser flow passage 9 according to the embodiment of the present invention cut along a vertical plane passing through the rotation axis of the turbine rotor 1, and FIG. 6 is a cross-sectional view of the flow passage shown in FIG. FIG. 7 is a diagram with an example of the measurement position of the cross-sectional area, FIG. 7 is a diagram showing a three-dimensional representation of the internal space of the simplified diffuser channel 9A in the embodiment of the present invention, and FIG. FIG. 9 is a diagram illustrating a change in the channel cross-sectional area of the simplified diffuser channel 9A in the embodiment of the present invention, and FIG. 9 is a simplified diffuser flow after the channel adjusting member is additionally installed in the embodiment of the present invention. It is a figure showing the change of the effective flow cross-sectional area of the path | route 9A.

  In FIG. 5, a circle Rk (k = 1, 2, 3,..., N) is a circle inscribed in both the cut surface 5S of the flow guide 5 and the cut surface 6S of the bearing cone 6, and the cut surface 5S. Is in contact with the contact point Fk and in contact with the cut surface 6S at the contact point Bk. The main flow point Pk is the midpoint of the straight line Lk connecting the contact point Bk and the contact point Fk. As shown in FIG. 6, the main flow point Pk determined in this way is spaced at an appropriate interval from the exit annulus 4 (P1), which is the start portion of the diffuser flow path 9, to the end portion (Pn) of the diffuser flow path 9. Set. Here, the main flow means an exhaust flow flowing at an equal distance from the flow guide 5 and the bearing cone 6 in the diffuser flow path 9, and the main flow point Pk is a point located on the main flow.

  When the main flow point P is set in this way, the flow path cross-sectional area (referred to as Sk) at the k-th main flow point Pk from the start portion of the diffuser flow path 9A has a straight line Lk around the rotation axis of the turbine rotor 1. This is the area of the rotating body that can be obtained by rotating. The solid shown in FIG. 7 (c) is obtained by obtaining a rotating body at each point by reducing the interval between the main flow points P1 to Pn to the limit, and smoothly connecting the rotating bodies. Is a side view thereof, and FIG. 7B is a sectional view thereof. That is, this solid indicates a simplified internal space of the diffuser flow path 9A.

  FIG. 8 shows a summary of changes in the channel cross-sectional area S in the exhaust flow direction of the diffuser channel 9 by calculating the channel cross-sectional area Sk at each main flow point Pk as described above. In FIG. 8, the horizontal axis indicates the distance from the exit annulus 4 (start point P1), and the vertical axis indicates the channel cross-sectional area S at each main flow point. The flow passage cross-sectional area S in FIG. 8 increases in proportion to the proportion of the flow passage from the start portion (P1) to the end portion (Pn) of the diffuser flow passage 9A (proportional portion 30). A portion (convex portion) 31 in which the cross-sectional area rapidly expands and the shape of the graph is convex upward is seen.

  The inventors of the present invention can form the diffuser flow path so that the effective flow cross-sectional area of the diffuser flow path gradually increases in proportion to the distance from the exit annulus, and the exhaust gas passes through the diffuser flow path. It has been found that the pressure loss generated in can be reduced. Based on this knowledge, the convex portion 31 in FIG. 8 in which the above-described proportional relationship is not established has a rapid increase in the cross-sectional area of the flow path and a rapid increase in the cross-sectional area of the effective flow. It is possible to specify that the flow path adjustment member 40 is provided and the effective flow cross-sectional area should be reduced (cross-sectional area adjustment position).

  A plurality of flow path adjustment members 40 are attached radially and symmetrically in the circumferential direction of the bearing cone 6 at the cross-sectional area adjustment points specified in this way. The shape of each flow path adjusting member 40 to be attached is determined based on the change in the cross-sectional area of the flow path measured by the method described above. In the case of the present embodiment in which the measurement result is as shown in FIG. 8, in accordance with the shape of the convex portion 31, the shape is tapered on the upstream side of the exhaust flow and is tapered on the downstream side of the exhaust flow. The flow path adjustment member 40 may be formed into a simple shape. FIG. 9 shows a change in the effective flow cross-sectional area of the diffuser flow path 9A after the flow path adjusting member 40 is additionally provided. In FIG. 9, since the flow path adjustment member 40 is additionally provided, the portion that is the convex portion 31 in FIG. 8 disappears, and the effective flow cross-sectional area gradually increases in proportion to the distance from the outlet ring zone 4. Such a flow path is formed. Further, when further optimizing the shape, attachment position, and number of attachments of the flow path adjustment member 40, numerical analysis of the exhaust flow in the diffuser flow path 9 is performed, and fine adjustment is made based on the analysis result. The final shape and the like may be determined.

  In the above description, the simplified method for measuring the channel cross-sectional area has been described. However, the channel cross-sectional area may be measured more accurately. In this case, for example, the distance between the contact point Bk and the contact point Fk at the main flow point Pk (that is, the length of the straight line Lk) is calculated using a cross section of a part of the diffuser flow path 9 as shown in FIG. Are calculated individually for all cross sections of the diffuser flow path 9 in the circumferential direction of the turbine rotor 1, and the results are summed, the flow path cross-sectional area at Pk can be calculated more accurately. In this way, if an accurate flow path cross-sectional area is obtained over the entire circumference of the diffuser flow path 9 and the change in the flow path cross-sectional area of the diffuser flow path 9 is clarified, an accurate adjustment member is obtained based on the change in the cross-sectional area. The shape, arrangement position, number of arrangements, etc. can be specified. Thereby, the pressure reduction in the diffuser flow path 9 can be further reduced, and the pressure recovery performance of the exhaust device can be improved.

  Next, the effect of this embodiment will be described.

  Research on optimizing a general diffuser flow path that can set the flow path relatively long even when considering the arrangement etc. has been conducted mainly by experiments so far to make pressure recovery effective. The conditions are discussed in detail. On the other hand, in the case of the diffuser flow path in the turbine exhaust device as the target in the present embodiment, the traveling direction of the steam discharged in the axial direction of the turbine rotor due to the restriction of the building and the arrangement with other devices It is necessary to recover the pressure while turning to the lower side where the condenser is installed at a very short distance. Therefore, the above general conditions for optimizing the diffuser channel cannot be directly applied, and performance has been improved by devising the shape of the flow guide and the shape of the bearing cone.

  By the way, many of the diffuser flow passages in the exhaust systems of existing turbine plants that have been used in the past have been improved mainly through experiments, and have been re-examined from the current point of view where numerical analysis has developed. In many cases, there is still room for improvement.

  When using a member such as a bearing cone whose shape has been devised as described above as a fundamental improvement measure for the diffuser flow path of such an existing exhaust system, replace the flow guide or the bearing cone or both. Thus, it is conceivable to optimize the shape of the diffuser flow path. However, the replacement work in that case is inevitably large and costly in terms of the amount of materials used, workability, workability, and the like. Needless to say, when the entire exhaust device is replaced, the operation is much larger than when only the members are replaced.

  On the other hand, the turbine exhaust device of the present embodiment is a plate-like member for reducing the effective flow cross-sectional area of the diffuser flow path 9 and includes a flow path adjusting member 40 provided on the bearing cone 6. ing. When the flow path adjusting member 40 is provided in the diffuser flow path 9 in this manner, the effective flow cross-sectional area is reduced to optimize the shape of the diffuser flow path without replacing the entire existing turbine exhaust system or the members constituting the turbine exhaust system. Therefore, the pressure recovery performance of the existing turbine exhaust system can be improved efficiently.

  Further, in order to further improve the workability of the mounting operation of the flow path adjusting member 40, avoid directly coupling the bearing cone 6 and the outer casing 8 (for example, in a portion where the bearing cone 6 is close to the inner side surface 17). , Avoid joining the members 6 and 8 by welding or the like.) The members 6 and 8 may be configured to be independent from each other. If comprised in this way, it will be avoided that the external force (for example, load and thermal strain) applied to the bearing cone 6 in the case of attachment work will be easily transmitted to the outer casing 8, and the external force will remain in the outer casing 8 afterwards. Since the work for preventing the heat treatment (for example, heating the entire outer casing 8 and gradually cooling it to remove the thermal strain) is unnecessary or reduced, the workability of the attachment work can be improved. Further, since the pressure in the outer casing 8 constituting the exhaust chamber 7 is low, the possibility of damage is increased when residual stress such as thermal strain is generated. However, if configured as described above, such damage is possible. Therefore, the reliability of the exhaust device can be maintained even after remodeling. In this regard, the technology for optimizing the shape of the diffuser flow path by exchanging the members described above can be applied to the outer casing or the like by separating the guide steel material supporting the flow guide, bearing cone, etc. from the inner casing or the outer casing at the time of replacement work. In view of the fact that thermal strain may remain, it can be pointed out that this embodiment exhibits an excellent effect.

  In addition, the flow path adjusting member 40 of the present embodiment is manufactured because it uses a plate-like member that is easy to process as compared with the case of using a replacement member that is manufactured with sufficient focus on the shape. It is easy, and if a plurality of them are arranged in the circumferential direction of the bearing cone 6 at a predetermined interval, the effective flow cross-sectional area is reduced, so that the amount of material used can be reduced.

  Furthermore, the flow path adjusting member 40 of the present embodiment is configured so that the effective flow cross-sectional area of the diffuser flow path 9 is determined based on the result of measuring the change in the cross-sectional area of the diffuser flow path 9 in the exhaust flow direction. The bearing cone 6 is provided so as to gradually expand in proportion to the distance from the bearing 4. As described above, based on the measurement result of the change in the cross-sectional area of the flow path, a place where the relationship between the distance from the outlet ring zone 4 and the cross-sectional area of the flow path rapidly deviates from the proportional relationship is a place where the adjustment member 40 is attached. By specifying the shape and the number of members 40 so that the relationship between the two is the same as that of the other parts, the performance of the exhaust device can be improved more accurately and effectively. Can do.

  In the above description, the diffuser flow path 9 has been described only for the bearing cone 6 and the flow guide 5. However, the inner side surface 17, which is a part of the outer casing 8, is a part of the diffuser flow path 9. In some cases, the channel cross-sectional area is rapidly expanded as described above. In such a case, if the flow path adjustment member 40 is attached to the inner side surface 17 as in the case of attachment to the bearing cone 6, the effective flow cross-sectional area can be optimized as described above. In addition, when attaching the flow path adjusting member 40 directly to the inner side surface 17 by welding or the like, measures are taken so that thermal strain does not remain in the outer casing (for example, the entire outer casing 8 is heated and gradually cooled to remove strain). ) Is required. In order to further improve the workability by avoiding such a treatment, for example, the adjustment member 40 is attached to the exhaust chamber 7 side (inside) of the inner side surface 17 while avoiding the attachment of the adjustment member 40 directly to the outer casing 8. A plate member (attachment member) for this purpose may be joined (for example, welded) to a member independent of the outer casing 8, and the adjustment member 40 may be appropriately attached via this attachment member. In addition, when attaching the adjustment member 40 to the outer casing 8 in this way (or when attaching via the attachment member), a member corresponding to the bearing cone 6 (bearing cover of the turbine rotor 1 having a weight-like shape) An exhaust device not provided with a member is also included.

It is a sectional side view showing typically the basic structure of the turbine exhaust system of an embodiment of the invention. It is sectional drawing in the II-II cross section in FIG. It is a sectional side view which expands and shows the turbine last stage vicinity in the turbine exhaust apparatus of embodiment of this invention in detail. FIG. 4 is a cross-sectional perspective view as seen from the direction of arrow IV in FIG. 1. It is sectional drawing which cut | disconnected the lower half side of the diffuser flow path in the turbine exhaust apparatus of embodiment of this invention by the vertical surface which passes along the rotating shaft center of a turbine rotor. It is the figure which attached | subjected an example of the measurement position of a flow-path cross-sectional area to sectional drawing shown in FIG. It is a perspective view which shows three-dimensionally the internal space of the simplified diffuser flow path in the turbine exhaust apparatus of embodiment of this invention. It is a figure showing the change of the flow-path cross-sectional area of the simplified diffuser flow path in the turbine exhaust apparatus of embodiment of this invention. It is a figure showing the change of the effective flow cross-sectional area of the simplified diffuser flow path after the flow-path adjustment member additional installation in the turbine exhaust apparatus of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbine rotor 3 Exhaust chamber inner casing 4 Final stage rotor blade exit ring 5 Flow guide 6 Bearing cone 7 Exhaust chamber 8 Exhaust chamber outer casing 9 Diffuser flow path 10 Final stage rotor blade 11 Diaphragm 15 Steam flow path 16 Final stage stationary blade 17 Inside Side surface 30 Proportional portion 31 Convex portion 40 Channel adjusting member P Main flow point S Channel cross-sectional area

Claims (7)

In a turbine exhaust device that guides exhaust after driving a turbine rotor to a condenser,
An exhaust chamber inner casing containing the turbine rotor;
A flow guide provided continuously on the outer periphery of the last rotor blade outlet ring of the turbine rotor;
A bearing cone provided continuously on the inner periphery of the final stage rotor blade outlet annulus,
An exhaust chamber outer casing that forms an exhaust chamber connected to the condenser, together with the bearing cone and the exhaust chamber inner casing,
An annular flow path formed by the flow guide and the bearing cone, the diffuser flow path for driving the turbine rotor and blowing the exhaust gas that has passed through the final stage rotor blade outlet ring zone into the exhaust chamber;
A turbine exhaust comprising a plate-like member for reducing an effective flow cross-sectional area of the diffuser flow path, and a flow path adjusting member provided on the bearing cone so as to face the diffuser flow path apparatus. In a turbine exhaust device that guides exhaust after driving a turbine rotor to a condenser,
An exhaust chamber inner casing containing the turbine rotor;
A flow guide provided continuously on the outer periphery of the last rotor blade outlet ring of the turbine rotor;
A bearing cone provided continuously on the inner periphery of the final stage rotor blade outlet annulus,
An exhaust chamber outer casing that forms an exhaust chamber connected to the condenser, together with the bearing cone and the exhaust chamber inner casing,
An annular flow path formed by an inner side surface of the flow guide, the bearing cone, and the inner wall surface of the exhaust chamber outer casing facing the final stage blade exit annular zone, and driving the turbine rotor A diffuser flow path for blowing the exhaust gas that has passed through the final stage rotor blade outlet annulus to the exhaust chamber;
Turbine exhaust comprising a plate-like member for reducing an effective flow cross-sectional area of the diffuser flow path, and a flow path adjusting member provided on the inner side surface so as to face the diffuser flow path apparatus. The turbine exhaust device according to claim 1 or 2,
The flow path adjusting member is provided in the bearing cone so that an effective flow cross-sectional area of the diffuser flow path gradually increases in proportion to a distance from the final stage rotor blade outlet annulus. Turbine exhaust system. The turbine exhaust device according to claim 1 or 2,
The flow path adjusting member has an effective flow cross-sectional area of the diffuser flow path from the final stage rotor blade outlet annulus based on a result of measuring a change in flow cross-sectional area in the exhaust flow direction of the diffuser flow path. A turbine exhaust device provided in the bearing cone so as to gradually expand in proportion to a distance. The turbine exhaust device according to any one of claims 1 to 4,
The turbine exhaust apparatus according to claim 1, wherein the flow path adjusting member is attached to the bearing cone radially about the rotation axis of the turbine rotor. The turbine exhaust device according to any one of claims 1 to 4,
The turbine exhaust device according to claim 1, wherein the flow path adjusting member is attached to the bearing cone symmetrically. In the modification method of the turbine exhaust device for guiding the exhaust after driving the turbine rotor to the condenser,
An exhaust chamber casing that encloses the turbine rotor, a flow guide continuously provided on the outer periphery of the final stage rotor blade outlet ring of the turbine rotor, and an inner periphery of the final stage rotor blade outlet ring A bearing cone provided continuously, an exhaust chamber outer casing that forms an exhaust chamber connected to the condenser together with the bearing cone and the exhaust chamber inner casing, an annular formed by the flow guide and the bearing cone In the bearing cone of the existing turbine exhaust device, which is a flow path, and includes a diffuser flow path that drives the turbine rotor and blows the exhaust gas that has passed through the final stage rotor blade outlet ring zone into the exhaust chamber,
A turbine exhaust device remodeling method characterized in that a flow path adjusting member, which is a plate-like member, is additionally provided so as to face the diffuser flow path to reduce an effective flow cross-sectional area in the diffuser flow path.

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