Steam turbine intake hole and method of its modification

FIELD: mechanical engineering; steam turbine.

SUBSTANCE: pair of ports of intake hole is arranged at opposite sides of steam turbine casing to provide passing of steam in opposite directions along circumference in ring-shaped steam chamber to first stages of turbine through axial opposite outlet holes. Parts of chamber in upper and lower casings has cross sections decreasing in common direction along circumference from sections of intake hole for steam to provide uniform flow of steam relative to chamber in common inner direction and through axial outlet holes and near holes.

EFFECT: provision of modification of steam turbine intake hole.

10 cl, 6 dwg

The present invention relates to the inlet of a steam turbine to provide essentially uniform mass flow and velocity during the flow of steam in the axial direction in the first stage (stage), and in particular, relates inlet for steam, having a linearly varying cross-sectional area in the circumferential direction from Windows inlet near the horizontal middle line to the top and bottom of the vertical axial line of the fixed casing, so that loss due to uneven flow, are minimized or eliminated. The present invention also relates to a method of modifying the existing steam turbines to ensure uniform mass flow and velocity in the inlet hole to the nozzles of the first stage.

In steam turbines for example, a steam turbine low pressure steam supplied from a section of high pressure, flows into the inlet port for low pressure steam, in General, includes a couple of Windows inlet basically on opposite sides of the turbine casing and the annular part. Steam flow through each window inlet for steam separated in opposite directions along the circumference passing through the arcuate section of the annular part, which in General has a pic is Joannou the cross-sectional area. As the flow follows the path along the circumference of the annular part of the inlet, the steam flows radially inwards and is deflected in the axial direction in the nozzle of the first stage. In steam turbines with separate axial flow radial internal thread of the annular part is divided to pass in opposite axial directions to the nozzles of the first stage. Example steam low-pressure turbine of this type is shown in U.S. patent No. 5593273.

Ideally, the inlet low pressure rejects pairs at an angle of 90° in axial flows with minimal losses. However, with the annular part of constant cross-section inside the housing is in communication with Windows inlet for steam, there are significant energy losses due to the lower vapor velocities, when he crosses the space along the circumference of the annular parts in directions from the Windows of the inlet. Essentially, at a constant cross-sectional area of the flow relative to the annular part mass flow rate is not constant, and is non-uniform velocity profile in the axial inlet hole (holes) to the nozzles of the first stage. In line with this, it is necessary to improve the inlet for the steam for the steam turbine in which the steam flow preserves the uniformity of the sun is m through the inlet, resulting in eliminating losses due to uneven flow and providing essentially uniform velocity profile as the occurrence of steam in the nozzle of the first stage.

In accordance with a preferred embodiment of the present invention provided with the inlet for the steam, designed to ensure a uniform mass flow rate of steam is essentially at a uniform velocity in the radial inner and axial directions for supply to the nozzles of the first stage. To achieve this, a relatively constant mass flow and a uniform velocity profile, the inlet port includes an annular casing defining a chamber essentially with gradually decreasing cross sectional area in General in the circumferential direction from Windows inlet for steam. By gradually decreasing the cross-sectional area essentially achieved a uniform mass flow rate and velocity.

In particular, in the preferred embodiment of the present invention is provided a steam turbine divided by the axial flow having a casing defined by the outer peripheral and side walls being in communication with Windows inlet for steam in General along the opposite sides of the turbine casing near the horizontal middle line. P is the current of steam through the open inlet is divided to pass along the upper and lower parts of the camera, defined by the casing. The cross-sectional area of the chamber decreases in the direction from each window of the inlet to the minimum cross-section areas located essentially in the middle between the Windows inlet steam vents along the opposite peripheral pathways couple of threads in the upper and lower housings containing parts of the camera. Thus, the casing in the General sector provides flow channels for a pair of gradually diminishing cross-sectional areas from Windows inlet to the minimum of the squares of the cross-section at a distance of about 90° Windows inlet. Due to a gradual decrease in the cross-sectional area, the mass flow rate and velocity remain essentially uniform in the internal radial and axial directions, resulting in reduced energy loss.

Casing inlet for steam can be provided as part of the original process equipment, or may be provided as a retrofit to existing inlet holes of the steam turbines. In the latter case, the annular part, determined by the original casing of a steam turbine, it is possible to provide one or more single arcuate housings having an external peripheral and side walls defining p is otechny channel gradually decreasing cross-section around the rotor. The housings may be made in advance, for example, for installation in each sector, or wall enclosures can be manufactured and attached to the turbine housing separately, to define flow channels gradually decreasing cross-sectional area in the direction from Windows inlet for steam. Moreover, provided the installation of separate walls in the housing to education casings inside.

In a preferred embodiment according to the present invention, in the steam turbine provided with the inlet for the steam, containing in total an annular casing having an outer surrounding peripheral wall and a pair located at a distance in the axial direction of the side walls, passing inside to determine in General the annular chamber inside the casing, and at least one thing in common annular outlet for steam, which is generally in the center of the casing, in communication with the chamber for the passage of steam in the axial direction to the outside through the exhaust hole in the first stage of the turbine, a couple of Windows inlet for steam, spaced each from each other relative to the casing for receiving steam and send the pair to the camera, where the camera actually has a gradually decreasing cross sectional area in General in the circumferential direction from Windows inlet resp is rste for steam, to ensure essentially uniform flow of steam relative to the camera in General in radial inner direction.

In an additional preferred embodiment according to the present invention in a steam turbine divided by the axial flow provided inlet for the steam, containing in total an annular casing having an outer surrounding peripheral wall and a pair located at a distance in the axial direction of the side walls, passing inward from the outer wall to define a common annular chamber inside the housing, a pair of Windows inlet for steam, located at a distance from each other relative to the casing for receiving steam and passing the received steam into the chamber, a pair located at a distance in the axial direction in a common annular outlet for steam, is in communication with the camera for the passage of steam in opposite axial directions through the outlet opening to the turbine stages, the chamber having a gradually decreasing cross sectional area in General in the circumferential direction from Windows inlet for steam, in order to ensure uniform flow of steam from the chamber through the outlet opening for steam and about them.

In an additional preferred embodiment according to the present invention in a steam turbine divided by the axial flow, having a housing with a ring-shaped part for receiving the pairs located at a distance along the circumference of the Windows inlet for steam and vapors located at a distance in the axial direction of the outlet for steam radially inside the annular part, for receiving a pair of annular parts to pass in opposite axial directions to the speed of the turbine, provided with a modified steam chamber to the annular part containing a lot in common arcuate shrouds, each of which has an outer peripheral wall and a pair located at a distance in the axial direction of the side walls, passing inward from the outer wall to define in General the arcuate channel, and the arcuate housings are located inside the annular part due to Windows inlet for steam, respectively, each of the arcuate channel has a gradually decreasing cross sectional area in General in the circumferential direction from Windows inlet for steam, in order to ensure uniform flow of steam from the chamber through the outlet opening for steam and about them.

In an additional preferred embodiment according to the present invention in a steam turbine divided by the axial flow having a housing with coleop the heat part for receiving the pairs located at a distance along the circumference of the Windows inlet for steam and vapors located at a distance in the axial direction of the outlet for steam, radially inside the annular part, for receiving a pair of annular parts to pass in opposite axial directions to the turbine stages, provided the modification of the inlet for steam, in order to obtain uniform velocity of steam flowing in the axial direction through the outlet opening for steam and about them, comprising stages of education many of the arcuate housings, each of which has an outer peripheral wall and a pair located at a distance in the axial direction of the side walls, passing inward from the outer wall to define in General the arcuate flow channel for a pair of decreasing cross-sectional area from one end to the opposite the end of the installation of casings in the form of a single enclosures or as a separate peripheral wall and side walls in the annular casing parts with large cross-section of its ends is in communication with Windows inlet and channels that are in communication with the axial exhaust hole pair, with the aim of passing a pair of essentially uniform velocity relative to the outlet in the opposite axial directions.

Moreover, the guide vanes in the Windows inlet can send pairs in opposite directions relative to the camera from OK who and the inlet. A second outlet for steam also serves for the passage of steam from the chamber in the axial direction opposite to the axial direction of the steam passing through the first exhaust hole pair.

Brief description of drawings

Figure 1 represents a perspective view of the inner part of the casing inlet for steam in accordance with the preferred embodiment of the present invention and is depicted along the vertical plane normal to the axis of rotation of the turbine rotor;

figure 2 represents an image disassembled casing 1;

figure 3 is a fragmentary view in cross section when viewed in the circumferential direction relative to the annular chamber;

figure 4 is a schematic cross-section of the upper half of the turbine casing, explaining the decrease in cross-sectional area in comparison with the known annular part of the inlet a constant cross-section;

figure 5 is a schematic representation of a decreasing cross-sectional areas of the inlet compared to the constant cross-sectional areas known techniques; and

6 is a view in cross section in the axial direction of the inlet according to a preferred variant of the implementation of this and is gaining.

1 shows a turbine housing, generally indicated by the reference position 8 and includes upper and lower sections 10 and 12 of a turbine casing, respectively, connected to each other along the horizontal middle line 14 and surrounding the shaft 16 of the rotor. It should be clear that the upper and lower sections 10 and 12 are one in the opposite axial directions and in this illustrated embodiment, form part of the steam turbine divided by the axial flow, in which the opposite in the axial direction stage of the turbine take couples through the annular axial channels or outlet 18. The upper and lower sections 10 and 12 of the housing define a window 20 of the inlet steam vents along the opposite sides of the body 8 of the turbine. For steam turbine low-pressure window 20 of the inlet holes receive high pressure steam from a section of high pressure (not shown) for its passage in General in the annular chamber 22 around the rotor 16.

Part 21 in the common annular chamber 22 in the upper housing 10 defines an outer peripheral wall 24 and a pair located at a distance in the axial direction of the side walls 26. In each of the Windows 20 of the inlet openings are provided guide vanes 28 for directing steam in General in the annular chamber 22. Part in the common annular chamber 22 of the lower housing 12 defined by the outer peripheral wall 30 and a pair of side walls 32. It should be clear that using Windows inlet steam vents along the opposite sides of the body 8 pairs in each box inlet is divided to pass into the upper section 10 and lower section 12, that is, the upper and lower parts 21 and 23 of the camera, respectively. Steam passes generally in the circumferential direction and radially inward, where he turns to pass axially through the axial outlet openings 18 in the first stage of the turbine.

In accordance with a preferred embodiment of the present invention the camera 21 and 23 in the upper and lower housings 10 and 12 respectively divided into arcuate flow channels gradually decreasing cross-sectional area from the window 20 to the inlet towards the middle location between the Windows inlet and along in the common annular chamber. For example, the camera 21 in the upper housing 10 is divided into two arcuate path flows, approximately 90° circumference. To provide a gradually decreasing constant cross-sectional area of the wall 22 defining the arcuate flow channel on the opposite sides of the camera parts agree with each other in the direction from the associated window 20 of the inlet. Alternatively, the outer peripheral wall 2 passes from the window 20 to the inlet along the directed radially inward of the arcuate path for the formation of a channel of decreasing cross-section, that is, forms a pair of evolvent. And side walls 22, and an outer peripheral wall 24 preferably converge towards each other and to the axis, respectively, so that the cross-sectional area of the flow decreases linearly from the open inlet, providing a uniform mass flow rate and velocity in the upper chamber 21. As shown in figure 1, the upper casing 10 provided with a pair of such arcuate path flows with a minimum cross-sectional area of a flow channel defined at the junction of the side walls and peripheral walls of each of the flow channels is essentially in the middle between the Windows 20 of the inlet, for example in a vertical plane passing through the axis of the rotor.

The lower housing 12 provided with a similar arcuate flow channels. Because open inlet openings are provided along opposite sides of the lower housing 12 near the horizontal middle line 14, the arcuate channels in the lower body 12 is slightly shorter in circumference than the arcuate flow channels in the upper housing 10. However, these channels also gradually reduced at a constant cross-sectional area in the circumferential direction from Windows inlet. Reducing the cross-sectional area through the extension of the peripheral wall 30 is Ostapenko radially inwards in the direction from the open inlet of a section of minimum cross-sectional area, located essentially in the middle between the Windows of the inlet, that is, a pair of evolvent. Alternatively, the side walls defining the arcuate channels in the lower body 10, can gradually converge towards each other in the circumferential direction from the open inlet. As in the upper section 10, the peripheral wall and the side walls of the lower chamber defining arcuate flow channels preferably are radially inward and converge, respectively, to define channels linearly decreasing cross-sectional areas, providing a uniform mass flow and velocity relative to the lower section.

Referring to figure 4 and 5, it should be clear that as the inlet for the steam turbine with axial flow presents the construction described above the inlet, in contrast to typically provide a ring-shaped parts with a constant cross-sectional area. Figs.4 and 5, the solid line 34 denotes a constant cross-sectional area known to the inlet, while the dotted lines 36 indicate the reduction in cross-sectional area in a portion of the circumference relative to the total annular inlet in accordance with the preferred embodiment of the present invention. N the figure 5 you can see, what peripheral wall 24, indicated by the dotted lines 36, forms a directed inside the top 38 is essentially in the middle between the Windows 20 of the inlet holes on the area of the minimum cross-sectional area. Similarly, the lower peripheral wall 30, indicated in figure 5 by the dotted lines 39, forms the apex 40 is essentially in the middle between the Windows 20 of the inlet.

As noted above, it is desirable to provide a uniform mass flow rate and velocity in radial inner direction and then in the axial direction to pass to the first turbine stages. Since the area gradually decreases from the Windows of the inlet with respect to each of the flow channels in the upper and lower housings 10 and 12, respectively, the mass flow rate and speed can remain essentially constant on each segment of a circle around the periphery of the rotor and, therefore, the axial flow in the first stage (stage) is essentially uniform and has a constant speed.

In accordance with a preferred embodiment of the present invention its inlet can be provided as part of the original equipment or as a modification of the existing steam turbines. As part of the original equipment walls as lateral and peripheral defining prot is cnie channels decreasing cross-sectional area from Windows inlet toward their middle portions, can be formed in one piece in the sections 10 and 12 of the housing during initial manufacture. It should also be understood that the peripheral wall 24 and 30 is not required to provide separately from the shells 10 and 12, but it is possible to form a whole, that is, to cast with shells 10 and 12. When required modification, the peripheral wall 24 and side walls 22 may be formed as a single partition. For example, a single section may contain portions of the side walls and part of the peripheral wall, forming one of the top sectors of the arcuate flow channel of decreasing cross-section, and can be installed as a node in an existing steam turbine. Then the second section is set similarly in the upper casing 10 and the sections are combined. Similarly, in the lower body 12 may be provided with one section containing walls 30 and 32, or it is possible to provide a pair of similar single covers. As a further alternative modification of existing steam turbines with inlet according to the present invention, the wall defining the arcuate flow channels gradually decreasing cross-sectional area, can be applied in the present case separately, for example as a separate steel plate. This is shown in figure 3, in which the individual steel plates to the side walls of which are a reference position 22. Similarly, the peripheral wall 24 can be made from the separate plates and welding in hull 10 and 12.

Although the invention has been described in connection with the embodiment, which is currently considered as the most convenient and preferred, it should be understood that the invention is not limited to those disclosed by the embodiment, but rather covers various modifications and equivalent devices according to the nature and scope of the claims appended claims.

1. Inlet for the steam in the steam turbine, containing

in General, the annular casing (10, 12)having an outer surrounding peripheral wall (24) and a pair located at a distance in the axial direction of the side walls (26), passing inside to determine essentially the annular chamber (22) inside the said casing, and at least one thing in common annular outlet opening (18) for a couple, located essentially in the center of the casing being in communication with the chamber for the passage of steam in the axial direction to the outside through the mentioned discharge port in the first stage of the turbine,

a couple of Windows (20) inlet for steam, located at a distance from each other relative to the casing, for receiving steam and send the pair to the camera,

said camera having, essentially, gradually what about decreasing the cross-sectional area in General in the circumferential direction from Windows inlet for steam to ensure that essentially uniform flow of steam relative to the camera in General in radial inner direction.

2. Inlet for steam according to claim 1, comprising guide vanes (28) in Windows inlet for directing steam in opposite directions relative to the camera from the window of the inlet.

3. Inlet for steam according to claim 1, in which the decreasing cross-sectional area provides uniform steam velocity in radial inner direction relative to the said chamber.

4. Inlet for steam according to claim 1, in which the decreasing cross-sectional area provides a uniform axial flow of steam from the axial outlet.

5. Inlet for steam according to claim 1, comprising a second outlet (18) for a couple, located generally in the center of the casing for the passage of steam from the chamber in the axial direction opposite to the axial direction of the steam passing through the first exhaust hole pair.

6. Inlet for steam according to claim 6, in which is mentioned the decreasing cross-sectional area provides uniform steam velocity in radial inner direction relative to the camera and essentially uniform axial flow at the outlet.

7. Inlet for the pair P1, in which the annular casing includes upper and lower sections (10, 12) of the housing, where each section includes a pair of arcuate flow channel of decreasing cross-sectional area in the direction from the respective Windows inlet, ending with a minimum cross-sectional area essentially in the middle between the Windows of the inlet.

8. The modification of the inlet for steam in the steam turbine divided by the axial flow having a housing with a ring-shaped part for receiving the pair of the pair located at a distance along the circumference of the window (20) inlet for steam and vapors located at a distance in the axial direction of the outlet (18) for a pair of radially inward of the annular part for receiving a pair of annular parts with the aim of passing in opposite axial directions to the turbine stages, where the specified modification to the inlet for steam in order to obtain uniform velocity of steam flowing in the axial direction through the mentioned outlet for steam and about them includes the stages of education many of the arcuate housings (10, 12), each of which has an outer peripheral wall (24, 30) and a pair located at a distance in the axial direction of the side walls (26, 32), passing inside from the outside the first wall, to determine, essentially, the arcuate flow channel for a pair of decreasing cross-sectional area from one end to the opposite end, the installation of casings in the form of a single enclosures or as a separate peripheral wall and side walls in the annular part of the housing with its ends of greater cross-section, is in communication with Windows inlet and channels that are in communication with the axial exhaust hole pair, with the aim of passing a pair of essentially uniform speed relative to the outlet openings in opposite axial directions.

9. The method of claim 8, comprising an enclosure inside the enclosure in the form of a single shrouds.

10. The method according to claim 8, which includes the installation of separate walls in the housing to education casings inside.