Flow guide device in regulating stage rear transition cavity of steam turbine
By setting up a flow diversion device after the turbine adjustment stage, including the cylinder section and the rotor section, the problems of flow unevenness and large energy loss after the adjustment stage are solved, and the effect of improving the available enthalpy drop of the adjustment stage and pressure stage and the unit performance is achieved.
Patent Information
- Application Number
- CN202510051122.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-13
- Publication Date
- 2025-04-18
AI Technical Summary
Under low load operating conditions, the flow after the adjustment stage has problems with unevenness and non-periodicity in the circumference of the steam flow, resulting in large loss of flow energy in the transition chamber, reducing the available enthalpy drop of the adjustment stage and pressure stage, and thus reducing the operating efficiency of the entire unit.
A flow guide device in the rear transition chamber of the turbine adjustment stage is designed, including a cylinder section and a rotor section. By setting a lower pressure section of the blade top near the top of the blade in the area behind the adjustment stage, the vortex is reduced; by setting a rounded section and a radial inclined section, the local loss of fluid during radial folding is reduced; by setting a top inlet guide section of the pressure stage, the steam flow enters the pressure stage static vanes and reduces energy loss.
The overall performance of the turbine is improved by reducing energy loss in the transition chamber and increasing the available enthalpy drop of the regulation and pressure stages, especially under low load operating conditions.
Smart Images
Figure CN119844170A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of steam turbines, and in particular to a flow guide device in a transition chamber after a regulating stage of a steam turbine. Background Art
[0002] With the current emphasis on energy conservation and emission reduction in the domestic power generation sector, people have higher and higher requirements for the performance of steam turbine units. In the context of the increasing proportion of new energy power generation installed capacity in the power generation sector, thermal power steam turbine units are also receiving more and more attention under low-load operating conditions.
[0003] In a steam turbine with a nozzle steam supply method, the performance of the regulating stage has an important impact on the operating efficiency of the entire unit due to its large enthalpy drop and high work. In the prior art, when the steam turbine operates under partial steam inlet conditions, the flow after the regulating stage has circumferential non-uniformity and non-periodicity problems, and the transition cavity between the regulating stage and the pressure stage often has a large height difference, and due to structural limitations, the axial width of the transition cavity is generally not large, but such a structure will also cause a rapid decrease in the flow radius within a small range, thereby causing a large energy loss. This energy loss will reduce the available enthalpy drop of the regulating stage and the pressure stage, thereby reducing the operating efficiency of the entire unit. Summary of the invention
[0004] In view of the problems in the prior art of large flow energy loss in the transition section chamber and high effective available enthalpy of the regulating stage and the pressure stage, the present application mainly provides a flow guide device in the transition chamber after the regulating stage of a steam turbine.
[0005] In order to achieve the above-mentioned purpose, the technical solution adopted in the present application is: a flow guide device in the transition chamber after the regulating stage of a steam turbine, comprising: a cylinder section, which is located on the inner wall surface of the high-pressure inner cylinder, the cylinder section includes a blade top pressure section, a chamfered section, a radial inclined section and a pressure stage top inlet guide section, and each section is connected in sequence; a rotor section, which is located on the rotor wall surface opposite to the inner wall surface of the high-pressure inner cylinder, the rotor section includes a rotor radial section, a rotor radial inclined section, a rotor chamfered section and a pressure stage root inlet guide section, and each section is connected in sequence; wherein, the cylinder section and the rotor section are located in the annular chamber formed by the annular high-pressure inner cylinder and the rotor of the steam turbine, and are located on the transition section after the regulating stage and before the pressure stage.
[0006] Optionally, the radial inclination angle of the radially inclined section of the rotor, the relative distance between the blade tip down pressure section and the regulating stage moving blade outlet section, the chamfer radius of the chamfer section, the chamfer angle of the chamfer section, and the height difference between the pressure stage top inlet guide section and the blade tip height of the pressure stage stationary blade are adjusted according to the steam flow conditions of the turbine.
[0007] Optionally, the radial height of the blade tip downward pressure section in the cylinder section is 0 to 5 mm greater than the radial height of the blade tip at the outlet of the regulating stage moving blade.
[0008] Optionally, the rounding radius of the rounded section in the cylinder section is 20 to 60 mm.
[0009] Optionally, the angle between the radially inclined section in the cylinder section and the flow vertical plane is 3° to 15°.
[0010] Optionally, the fillet radius of the pressure stage top inlet guide section in the cylinder section is 5 to 20 mm, wherein the pressure stage top inlet guide section is 0 to 5 mm higher than the blade tip height of the pressure stage stationary blade.
[0011] Optionally, the angle between the rotor radial inclined section in the rotor section and the flow vertical plane is 3° to 15°.
[0012] Optionally, the chamfer radius of the rotor rounded section in the rotor segment is 20 mm to 50 mm.
[0013] Optionally, the relative distance between the cylinder section and the rotor section in the steam turbine is adjusted according to the actual steam flow conditions of the steam turbine. The flow chamber of the flow guide device is a rotating body structure as a whole, which is easy to cast. Without increasing the difficulty of casting processing, it can reduce or completely eliminate the vortex in this area by setting a blade top pressure section in the area near the blade top behind the regulating stage moving blade, thereby reducing the flow energy loss at the blade top; by setting a rounded section and a radially inclined section behind the blade top pressure section of the cylinder section, the local loss generated by the radial deflection of the fluid is reduced; by setting a pressure stage top inlet guide section at the rear section of the cylinder section, the steam can smoothly enter the pressure stage stationary blade after flowing through the rounded section of the pressure stage top inlet guide section. , thereby reducing the energy loss caused by the deflection of the steam flow here, and at the same time reducing or eliminating the existence of small vortices caused by the structural height difference of the stator blades entering the pressure stage, thereby reducing the flow energy loss; by arranging a radial inclined section in the rotor section, the steam flow forms a vortex when flowing through here, and the inclined structure can minimize the size of the vortex, thereby reducing the flow energy loss; by arranging the rotor chamfered section and the pressure stage root inlet guide section, the steam flow is guided to the greatest extent in these two parts, guiding the vortex to the bottom of the mainstream channel, reducing the mixing loss with the mainstream. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0015] Figure 1 It is a schematic diagram of the structure of the transition chamber after the regulating stage in the prior art;
[0016] Figure 2 This is a schematic diagram of the structure of a regulating stage rear transition chamber of a steam turbine regulating stage rear transition chamber of the present application;
[0017] Figure 3 It is a schematic diagram of the steam flow in the transition chamber after the regulating stage in the prior art;
[0018] Figure 4 It is a schematic diagram of steam flow in a transition chamber after a regulating stage of a flow guide device in a transition chamber after a regulating stage of a steam turbine of the present application;
[0019] Figure numerals: 1 is the blade top downward pressure section in the cylinder section, 2 is the rounded section in the cylinder section, 3 is the radial inclined section in the cylinder section, 4 is the pressure stage top inlet guide section in the cylinder section, 5 is the rotor radial section, 6 is the rotor radial inclined section, 7 is the rotor rounded section, 8 is the pressure stage root inlet guide section in the rotor section.
[0020] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION
[0021] The preferred embodiments of the present application are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present application can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present application.
[0022] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.
[0023] With the current emphasis on energy conservation and emission reduction in the domestic power generation sector, people have higher and higher requirements for the performance of steam turbine units. In the context of the increasing proportion of new energy power generation installed capacity in the power generation sector, thermal power steam turbine units are also receiving more and more attention under low-load operating conditions.
[0024] In a steam turbine with a nozzle steam supply method, the performance of the regulating stage has an important impact on the operating efficiency of the entire unit due to its large enthalpy drop and high work. In the prior art, when the steam turbine operates under partial steam inlet conditions, the flow after the regulating stage has circumferential non-uniformity and non-periodicity problems of steam flow, and there is often a large height difference between the transition cavity between the regulating stage and the pressure stage. Due to structural limitations, the axial width of the transition cavity is generally not large, but such a structure will also cause a rapid decrease in the flow radius within a small range, thereby causing a large energy loss. This energy loss will reduce the available enthalpy drop of the regulating stage and the pressure stage, thereby reducing the operating efficiency of the entire unit.
[0025] In response to the above problems, the present application sets a flow guide structure after the turbine regulating stage to reduce the energy loss in the transition chamber after the regulating stage, thereby increasing the available enthalpy drop of the regulating stage and the pressure stage and improving the overall performance of the unit.
[0026] Figure 2 Schematic diagram of the structure of the transition chamber after the adjustment stage of a flow guiding device of the present application, such as Figure 2 As shown, the flow guide device of the present application includes: a cylinder section, which is located on the inner wall surface of the high-pressure inner cylinder, and the cylinder section includes a blade top pressure section, a chamfered section, a radial inclined section and a pressure stage top inlet flow guide section, and each section is connected in sequence; a rotor section, which is located on the rotor wall surface opposite to the inner wall surface of the high-pressure inner cylinder, and includes a rotor radial section, a rotor radial inclined section, a rotor chamfered section and a pressure stage root inlet flow guide section, and each section is connected in sequence; wherein, the cylinder section and the rotor section are located in the annular chamber formed by the annular high-pressure inner cylinder and the rotor of the steam turbine, and are located on the transition section after the regulating stage and before the pressure stage.
[0027] The device has a simple casting process by making the flow chamber as a whole a rotating body structure. Without increasing the difficulty of casting processing, the device can reduce or completely eliminate the vortex in this area by setting a blade top pressure section in the area near the blade top behind the regulating stage moving blade, thereby reducing the flow energy loss at the blade top; by setting a rounded section and a radially inclined section behind the blade top pressure section of the cylinder section, the local loss of the fluid during radial deflection is reduced; by setting a pressure stage top inlet guide section at the rear section of the cylinder section, the steam can smoothly enter the pressure stage stationary blade after flowing through the rounded section of the pressure stage top inlet guide section. Thereby reducing the energy loss caused by the deflection of the steam flow here, and at the same time reducing or eliminating the existence of small vortices caused by the structural height difference of the stator blades entering the pressure stage, thereby reducing the flow energy loss; by arranging a radial inclined section in the rotor section, a vortex is formed when the steam flow flows through this point, and the inclined structure can minimize the size of the vortex, thereby reducing the flow energy loss; by arranging the rotor chamfered section and the pressure stage root inlet guide section, the steam flow is guided to the greatest extent in these two parts, guiding the vortex to the bottom of the mainstream channel, thereby reducing the mixing loss with the mainstream.
[0028] Specifically, the cylinder section and the rotor section are located in a transition section after the regulating stage outlet and before the pressure stage inlet, and in actual application, according to the steam flow conditions of the steam turbine, the radial inclination angle of the radial inclined section and the vertical plane of the flow, the height of the blade top down-pressure section, the chamfer angle of the chamfered section, the height difference between the outlet straight section in the pressure stage top inlet guide section and the blade top height of the pressure stage stator blade are adjusted. In addition, according to the actual steam flow conditions of the steam turbine, the distance between the cylinder section and the rotor section in the steam turbine is adjusted, thereby reducing the energy loss caused by the upper and lower vortices, thereby further improving the performance.
[0029] Preferably, the height of the blade tip downward pressure section in the cylinder section is 0 to 5 mm greater than the blade tip height of the regulating stage moving blade outlet, the radius of the rounded section in the cylinder section varies in the range of 20 to 60 mm, the angle between the radial inclined section in the cylinder section and the vertical plane of the flow is 3° to 15°, the radius of the rounded section in the pressure stage top inlet guide section in the cylinder section varies in the range of 5 to 20 mm, wherein the pressure stage top inlet guide section is 0 to 5 mm higher than the blade tip height of the pressure stage stationary blade, the angle between the rotor radial inclined section in the rotor section and the vertical plane of the flow is 3° to 15°, and the radius of the chamfered section of the rotor in the rotor section varies in the range of 20 mm to 50 mm.
[0030] For example, taking a 300MW direct air-cooled condensing steam turbine with a flow rate of 256.7kg / s, a total pressure of 16.2MPa at the regulating stage inlet, and a total temperature of 535℃ as an example, the blade tip downward pressure section (1) is 4mm higher than the blade tip of the regulating stage moving blade outlet; the radius R1 of the rounded section (2) is 40mm, and the angle between the radially inclined section (3) and the flow vertical plane is 10°; the rounded R2 in the pressure stage top inlet guide section (4) is 15mm, and the straight section is 1mm higher than the pressure stage inlet top. Among them, the angle between the rotor radially inclined section (6) in the rotor section and the flow vertical plane is 10°; the rounded radius R3 of the rotor rounded section (7) is 50mm; the pressure stage root inlet guide section (8) is consistent with the rotor radius at the pressure stage stator blade outlet.
[0031] In a specific embodiment of the present application, Figure 1 Schematic diagram of the structure of the transition chamber after the adjustment stage in the prior art. Figure 2 and Figure 1 Through CFD analysis of the structure, it can be known that the available enthalpy drop of the regulating stage of this application is increased by 1.51%, the available enthalpy drop of the first stage of the pressure stage is increased by 1.19%, and the power of the regulating stage and the first stage of the pressure stage is increased by 326kW, accounting for 1.41% of the total power of the two stages and 0.35% of the total power of the high-pressure cylinder of this steam turbine. In other words, the structure adopted in this application can improve the efficiency of the high-pressure cylinder of a 300MW steam turbine by about 0.35%.
[0032] In a specific embodiment of the present application, Figure 3 is a schematic diagram of the steam flow in the transition chamber after the regulating stage in the prior art, and Figure 4 It is a schematic diagram of the steam flow in the transition chamber after the regulating stage of the flow guide device of the present application.
[0033] Specifically, Figure 3 and Figure 4 As shown, the steam flow direction of the present application is compared with the steam flow direction in the transition chamber after the regulating stage of the prior art. The present application reduces the vortex in this area by setting a blade tip down pressure section in the area near the blade tip behind the regulating stage moving blade, thereby reducing the flow energy loss at the blade tip; by setting a radial inclined section in the rotor section, a vortex is formed when the steam flow flows through this area, and the inclined structure can minimize the size of the vortex, thereby reducing the flow energy loss; by setting the rotor chamfer section and the pressure stage root inlet guide section, the steam flow is guided to the maximum extent in these two parts, and the vortex is guided to the bottom of the mainstream channel, thereby reducing the mixing loss with the mainstream.
[0034] In a specific embodiment of the present application, the flow guide device of the present application is applicable to a nozzle-regulated steam turbine, and is applicable to improving the efficiency of the steam turbine under all operating conditions, and is particularly applicable to a steam turbine in which the regulating stage and the pressure stage are close and the height difference is large. The flow guide device of the present application includes two parts, a cylinder section structure and a rotor section structure. In practical applications, one part can be used alone or both structures can be used at the same time, that is, only using any one of the above two structures can effectively reduce the energy loss of the transition chamber, and improve the available enthalpy drop of the regulating stage and the pressure stage.
[0035] The above description is only an embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structural transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.
Claims
1. A flow guide device in a transition chamber after a steam turbine regulating stage, characterized in that: include: The cylinder section is located on the inner wall of the high-pressure inner cylinder, and includes a blade tip downward pressure section, a rounded section, a radially inclined section, and a pressure stage top inlet guide section, and each section is connected in sequence; A rotor section, which is located on the rotor wall surface opposite to the inner wall of the high-pressure inner cylinder, and comprises a rotor radial section, a rotor radial inclined section, a rotor rounded section and a pressure stage root inlet guide section, and each section is connected in sequence; The cylinder section and the rotor section are located in an annular chamber formed by an annular high-pressure inner cylinder and a rotor of the steam turbine, and are located on a transition section after the regulating stage and before the pressure stage.
2. The flow guide device in the transition chamber after the regulating stage of the steam turbine according to claim 1, characterized in that: The radial inclination angle of the rotor radial inclination section, the relative distance between the blade top pressure section and the regulating stage moving blade outlet section, the chamfer radius of the chamfer section, the chamfer angle of the chamfer section, and the height difference between the pressure stage top inlet guide section and the blade top height of the pressure stage stationary blade are adjusted according to the steam flow conditions of the turbine.
3. The flow guide device in the transition chamber after the regulating stage of the steam turbine according to claim 1, characterized in that: The radial height of the blade tip downward pressure section in the cylinder section is 0 to 5 mm greater than the radial height of the blade tip at the outlet of the regulating stage moving blade.
4. The flow guide device in the transition chamber after the regulating stage of a steam turbine according to claim 1, characterized in that: The rounding radius of the rounded section in the cylinder section is 20 to 60 mm.
5. The flow guide device in the transition chamber after the regulating stage of a steam turbine according to claim 1, characterized in that: The angle between the radially inclined section in the cylinder section and the flow vertical plane is 3° to 15°.
6. The flow guide device in the transition chamber after the regulating stage of a steam turbine according to claim 1, characterized in that: The rounding radius of the pressure stage top inlet guide section in the cylinder section is 5 to 20 mm, wherein the pressure stage top inlet guide section is 0 to 5 mm higher than the blade tip height of the pressure stage stationary blade.
7. The flow guide device in the transition chamber after the regulating stage of a steam turbine according to claim 1, characterized in that: The included angle between the rotor radial inclined section in the rotor section and the flow vertical plane is 3° to 15°.
8. The flow guide device in the transition chamber after the regulating stage of a steam turbine according to claim 1, characterized in that: The chamfer radius of the rotor rounded section in the rotor section is 20 mm to 50 mm.
9. The flow guide device in the transition chamber after the regulating stage of a steam turbine according to claim 1, characterized in that: The relative distance between the cylinder section and the rotor section in the steam turbine is adjusted according to the actual steam flow conditions of the steam turbine.