600mw supercritical steam turbine nozzle set structure suitable for deep peak shaving

Abstract

This application discloses a nozzle group structure for a 600MW supercritical steam turbine suitable for deep peak shaving, belonging to the field of steam turbine technology. Its main purpose is to adapt to the current deep peak shaving conditions of thermal power generation steam turbine units. By reducing the opening adjustment of the steam turbine regulating valve, it achieves efficient operation of the steam turbine unit under low load conditions and reduces the occurrence of valve stem breakage accidents. The main technical solution of this application is as follows: The nozzle group structure for a 600MW supercritical steam turbine suitable for deep peak shaving includes a steam chamber cavity; four nozzle groups are uniformly arranged circumferentially within the steam chamber cavity; the four nozzle groups are symmetrically arranged, with the symmetry plane being the horizontal midline of the steam chamber cavity; the number of steam passages and the steam flow area of ​​the four nozzle groups are non-uniformly arranged.

Description

Technical Field

[0001] This application belongs to the field of steam turbine technology, specifically relating to a nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving. Background Technology

[0002] The nozzle group flow area of ​​the traditional 600MW supercritical steam turbine is designed based on the rated heat consumption acceptance condition (THA). The regulating stage nozzle group has a flow margin of 8% to 12%, and the flow area is relatively large. In addition, the four nozzle groups adopt a symmetrical arrangement structure with equal flow areas and the same number of steam passages. In the early stage of the unit's construction, due to the tight domestic power supply, it played a role in the thermal power unit to generate more and operate at full capacity to serve economic construction.

[0003] With the widespread construction and application of new energy sources such as wind, solar, and nuclear power, thermal power generating units have shifted from traditional main baseload power sources to system-guaranteed, regulated, and backup power sources. Their core function has changed from "providing stable power at full capacity year-round" to deep and rapid peak shaving and supporting the consumption of new energy sources. When steam turbine units operate under deep peak shaving for extended periods and in low-load ranges, the opening of the turbine regulating valve needs to be significantly reduced to match the low-load output demand, thereby controlling the amount of steam entering the turbine and matching the power generation load demanded by the grid. However, when the turbine regulating valve opening is too small, it is prone to causing severe valve vibration, which can lead to valve stem breakage and seriously affect the operational safety of the unit. At the same time, the turbine regulating valve is in a small-opening throttling state for a long time, resulting in a significant increase in throttling losses, a decrease in high-pressure cylinder efficiency, and a deterioration in the unit's operational economy. Summary of the Invention

[0004] In view of this, this application provides a nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving. The main purpose is to adapt to the current deep peak shaving conditions of thermal power steam turbine units. By reducing the opening adjustment of the steam turbine regulating valve, the steam turbine unit can operate efficiently under low load conditions and reduce the occurrence of valve stem breakage accidents.

[0005] To achieve the above objectives, this application mainly provides the following technical solutions: This application provides a nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving, including: Steam chamber cavity; Four nozzle groups are evenly arranged circumferentially inside the steam chamber. The four nozzle groups are arranged symmetrically, with the plane of symmetry being the horizontal midline of the steam chamber. The number of steam passages and the steam flow area of ​​the four nozzle groups are not uniformly arranged.

[0006] Optionally, the four nozzle groups include a first nozzle group, a second nozzle group, a third nozzle group, and a fourth nozzle group; The first nozzle group and the third nozzle group are located on one side of the horizontal split plane of the steam chamber cavity, and the second nozzle group and the fourth nozzle group are located on the other side of the horizontal split plane of the steam chamber cavity; The number of steam passages in the first nozzle group, the second nozzle group, and the third nozzle group is the same, and all of them have a greater number of steam passages than the fourth nozzle group.

[0007] Optionally, the steam flow areas of the first nozzle group, the second nozzle group, and the third nozzle group are equal and all are larger than the steam flow area of ​​the fourth nozzle group.

[0008] Optionally, the nozzle assembly includes stationary blades with an installation angle of 69°21′, a blade width of 48.39 mm, a blade height of 39 mm, and a steam outlet edge thickness of 0.5 mm.

[0009] Optionally, the height of the stationary blade is 2 mm smaller than the height of the moving blade; The tip height of the moving blade is 1.5 mm higher than the tip height of the stationary blade; The root height of the moving blade is 0.5 mm lower than that of the stationary blade.

[0010] Optionally, the pitch circle radius of the nozzle assembly is 522.1 mm; the pitch circle throat size of the nozzle assembly is φ4.12 mm.

[0011] Optionally, the nozzle assembly structure for the 600MW supercritical steam turbine suitable for deep peak shaving also includes a reinforcing ring; The reinforcing ring is fixedly installed on the steam outlet side of the steam chamber, and the four nozzle groups are all fixedly installed on the inner wall of the reinforcing ring; The inner wall of the reinforcing ring and the outlet side of the nozzle assembly are provided with a steam seal structure, which is arranged radially opposite to the rotor blade shroud.

[0012] Optionally, the steam seal structure includes two long-tooth steam seal baffles and two short-tooth steam seal baffles arranged sequentially along the axial direction from the outlet side of the nozzle assembly; The sealing tooth height of the long-toothed steam seal barrier is greater than the sealing tooth height of the short-toothed steam seal barrier. Both the long-tooth steam seal plate and the short-tooth steam seal plate are fixedly disposed on the inner wall of the reinforcing ring, and form a radial sealing gap with the moving blade shroud of the rotor.

[0013] Optionally, the steam chamber cavity is provided with a steam chamber inlet passage, and a sealing ring assembly is provided between the steam chamber inlet passage and the steam turbine inlet pipe; The sealing ring assembly is located between the outer wall of the turbine inlet pipe and the inner wall of the steam chamber inlet passage. The sealing ring assembly includes a locking ring, a four-way ring, a guide ring, and a sealing ring. The sealing ring is used to achieve a seal between the steam chamber inlet and the turbine inlet pipe; The guide ring is used to support and guide the sealing ring; The four-ring is used to cooperate with the locking ring to axially press and position the sealing ring and the guide ring.

[0014] Optionally, the sealing ring has a staggered overlapping structure to form a compensating seam.

[0015] By employing the above technical solution, this application has at least the following beneficial effects: The nozzle group structure for a 600MW supercritical steam turbine suitable for deep peak shaving provided in this application, by setting the number of steam passages and steam flow area of ​​the four nozzle groups to a non-uniform structure, allows different nozzle groups to be combined to adapt to the efficient operation of the steam turbine under various operating conditions. When the steam turbine is operating at low load during deep peak shaving, the nozzle group with fewer steam passages and smaller steam flow area can be put into operation first. It can match the low load output demand without relying on drastically closing the steam turbine regulating valve, thereby reducing the opening adjustment of the steam turbine regulating valve, reducing the valve vibration amplitude, avoiding valve stem breakage, ensuring the operating safety of the steam turbine. At the same time, it can avoid the steam turbine regulating valve being in a small opening throttling state for a long time, reducing throttling losses, improving the operating efficiency of the high-pressure cylinder, and improving the operating economy of the steam turbine. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the steam chamber cavity of an optional embodiment of this application; Figure 2 This is a schematic diagram of one side of the horizontal split plane of the steam chamber cavity in one optional embodiment of this application; Figure 3 This is a schematic diagram of the structure of the first nozzle group and the third nozzle group in an optional embodiment of this application; Figure 4 This is a schematic diagram of the structure on the other side of the horizontal split plane of the steam chamber cavity in one optional embodiment of this application; Figure 5 This is a schematic diagram of the structure of the second nozzle group and the fourth nozzle group according to an optional embodiment of this application; Figure 6 This is a top view of the steam chamber cavity of an optional embodiment of this application; Figure 7 This is a schematic diagram of the reinforcing ring in one optional embodiment of this application; Figure 8This is a schematic diagram of the reinforcing rib in one optional embodiment of this application; Figure 9 This is a schematic diagram of the sealing ring assembly according to an optional embodiment of this application; Figure 10 This is a schematic diagram of the sealing ring structure of an optional embodiment of this application.

[0017] The reference numerals in the attached figures are as follows: 1. Steam chamber cavity; 11. Steam chamber inlet; 12. Positioning bolt; 13. Fastening bolt; 14. Insert key; 15. Positioning groove; 2. First nozzle group; 3. Second nozzle group; 4. Third nozzle group; 5. Fourth nozzle group; 6. Reinforcing ring; 61. Reinforcing rib; 7. Steam seal structure; 71. Long tooth steam seal baffle; 72. Short tooth steam seal baffle; 8. Sealing ring assembly; 81. Locking ring; 82. Four-way ring; 83. Guide ring; 84. Sealing ring; 841. Compensation joint. Detailed Implementation

[0018] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0020] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0021] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0022] See also Figures 1 to 10 As shown, according to an embodiment of this application, a nozzle group structure for a 600MW supercritical steam turbine suitable for deep peak shaving is provided, including a steam chamber cavity 1; four nozzle groups are uniformly arranged circumferentially inside the steam chamber cavity 1; the four nozzle groups are symmetrically arranged, with the symmetry plane being the horizontal mid-section of the steam chamber cavity 1; the number of steam passages and the steam flow area of ​​the four nozzle groups are non-uniformly arranged.

[0023] The nozzle group structure for a 600MW supercritical steam turbine suitable for deep peak shaving provided in this application embodiment sets the number of steam passages and the steam flow area of ​​the four nozzle groups to be non-uniform, so that different nozzle groups correspond to different flow capacities. When the steam turbine unit is operating at low load during deep peak shaving, the nozzle group with fewer steam passages and smaller steam flow area can be put into operation first. It can match the low load output demand without relying on drastically closing the steam turbine regulating valve, thereby reducing the opening adjustment of the steam turbine regulating valve, reducing the valve vibration amplitude, avoiding valve stem breakage, ensuring the operating safety of the steam turbine unit, and at the same time avoiding the steam turbine regulating valve being in a small opening throttling state for a long time, reducing throttling losses, improving the operating efficiency of the high-pressure cylinder, and improving the operating economy of the steam turbine unit.

[0024] The steam chamber 1 is a pressure-bearing shell with a chamber, located at the steam inlet end of the high- and intermediate-pressure outer cylinder of the steam turbine, and is detachably fixed to the inner side of the high- and intermediate-pressure outer cylinder. In actual application, high-temperature and high-pressure steam first enters the interior of the steam chamber 1, and then is distributed by the steam chamber 1 to each nozzle group.

[0025] Specifically, the steam chamber 1 has a horizontally split structure, comprising an upper half and a lower half. The lower half is fixedly connected to the high-pressure outer cylinder of the turbine via positioning bolts 12, and the upper half is fastened to the lower half via fastening bolts 13, forming a complete steam chamber 1. Further, positioning grooves 15 are formed along the circumference of the upper and lower half of the steam chamber 1 on their opposite sidewalls, and the planes containing the positioning grooves 15 on the upper and lower half are perpendicular to the horizontal midline of the steam chamber 1. The high-pressure outer cylinder of the turbine is provided with a first boss structure that mates with the positioning grooves 15. The first boss structure is embedded in and fits snugly with the positioning grooves 15, restricting the steam chamber 1 from moving axially along the turbine. In addition, mounting slots for embedded keys 14 are respectively provided at the top of the upper half and the bottom of the lower half, and embedded keys 14 are installed within these mounting slots. The high- and intermediate-pressure outer cylinder is also equipped with a second boss structure that mates with the embedded key 14. The second boss structure is embedded in the mounting groove of the embedded key 14, and the embedded key 14 and the second boss structure abut against each other, restricting the steam chamber cavity 1 from rotating in the circumferential direction. This achieves a detachable connection between the steam chamber cavity 1 and the high- and intermediate-pressure outer cylinder of the turbine, allowing for the replacement of the entire nozzle assembly by replacing the steam chamber cavity 1. This adapts to the long-term deep peak-shaving operation of the turbine unit without requiring flow path modifications to the turbine unit, reducing modification costs, shortening the modification cycle, and enhancing applicability.

[0026] The steam chamber cavity 1 has four steam inlet channels 11 symmetrically arranged vertically. Correspondingly, four nozzle groups are evenly arranged circumferentially inside the steam chamber cavity 1. In actual application, high-temperature and high-pressure steam enters the steam chamber cavity 1 through the four steam inlet channels 11, and is then distributed by the steam chamber cavity 1 to the four nozzle groups, providing stable and uniform steam inlet conditions for the nozzle groups.

[0027] Specifically, the four nozzle groups are arranged symmetrically with the horizontal midline of the steam chamber 1 as the symmetrical plane, and the number of steam passages and the steam flow area of ​​the four nozzle groups are not uniform. In some examples, one nozzle group may have fewer steam passages than the other three groups, making the steam flow area of ​​that nozzle group smaller; in other examples, the number of steam passages and the steam flow area of ​​the four nozzle groups are different, forming a multi-stage flow capacity configuration.

[0028] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figures 2 to 5 As shown, the four nozzle groups include a first nozzle group 2, a second nozzle group 3, a third nozzle group 4, and a fourth nozzle group 5; the first nozzle group 2 and the third nozzle group 4 are located in the upper half of the horizontal mid-section of the steam chamber cavity 1, and the second nozzle group 3 and the fourth nozzle group 5 are located in the lower half of the horizontal mid-section of the steam chamber cavity 1; the first nozzle group 2, the second nozzle group 3, and the third nozzle group 4 have the same number of steam passages, and all of them have a greater number of steam passages than the fourth nozzle group 5.

[0029] In this embodiment, the number of steam passages in the first nozzle group 2, the second nozzle group 3, and the third nozzle group 4 is the same, and all are greater than the number of steam passages in the fourth nozzle group 5. This ensures sufficient flow capacity during high-load operation of the turbine unit while providing a dedicated small-flow nozzle group for low-load deep peak shaving conditions. This allows the turbine unit to operate at low loads by simply engaging the steam inlet combination of the first nozzle group 2 and the fourth nozzle group 5, which has fewer steam passages. It eliminates the need to significantly reduce the opening of the turbine regulating valve controlling the fourth nozzle group 5 to meet the output requirements for deep peak shaving. This reduces the throttling loss and vibration amplitude of the turbine regulating valve, avoids valve stem breakage, and improves the operating efficiency of the high-pressure cylinder and the safety and economy of the turbine unit operation.

[0030] Along the direction of rotor rotation, the four nozzle groups are arranged in the following order: first nozzle group 2, third nozzle group 4, fourth nozzle group 5, and second nozzle group 3. Here, the rotor is a steam turbine rotor, such as a high-pressure or intermediate-pressure rotor.

[0031] Specifically, in this embodiment, the number of steam passages in the first nozzle group 2, the second nozzle group 3 and the third nozzle group 4 are all 46, and the number of steam passages in the fourth nozzle group 5 is 38.

[0032] In the above embodiments, see Figure 2 and Figure 4 As shown, the steam flow areas of the first nozzle group 2, the second nozzle group 3, and the third nozzle group 4 are equal, and all are greater than the steam flow area of ​​the fourth nozzle group 5.

[0033] In this embodiment, the pitch circle radius of the first nozzle group 2, the second nozzle group 3, the third nozzle group 4 and the fourth nozzle group 5 are all 522.1 mm, and the pitch circle throat size is φ4.12 mm.

[0034] Specifically, in this embodiment, the steam flow area of ​​the first nozzle group 2, the second nozzle group 3, and the third nozzle group 4 is all 7391 mm². 2 The steam flow area of ​​the fourth nozzle group 5 is 6106 mm². 2In practical applications, when the turbine unit operates at a low load of 30% to 40% of its rated load, the first nozzle group 2 and the fourth nozzle group 5 are combined. The turbine regulating valve associated with the first nozzle group 2 remains fully open. The power generation load of the turbine unit is controlled by adjusting the opening of the turbine regulating valve associated with the fourth nozzle group 5, achieving efficient operation under low load conditions. When the turbine unit operates at 40% to 75% of its rated load, the first nozzle group 2, the third nozzle group 4, and the fourth nozzle group 5 are combined. The turbine regulating valves associated with the first nozzle group 2 and the third nozzle group 4 remain fully open. The power generation load of the turbine unit is controlled by adjusting the opening of the turbine regulating valve associated with the fourth nozzle group 5. The turbine regulating valve opening controls the power generation load of the steam turbine unit, achieving efficient operation under 40% to 75% rated load conditions. When the steam turbine unit is in a high-load operation state of 75% to 100% rated load, the first nozzle group 2, the second nozzle group 3, the third nozzle group 4 and the fourth nozzle group 5 are combined. The steam turbine regulating valves matched with the first nozzle group 2, the second nozzle group 3 and the fourth nozzle group 5 are kept fully open. The power generation load of the steam turbine unit is controlled by adjusting the opening of the steam turbine regulating valve matched with the third nozzle group 4, achieving efficient operation under high-load conditions of 75% to 100% rated load.

[0035] In the above embodiments, see Figure 2 As shown, the first nozzle group 2 and the third nozzle group 4, located on one side of the horizontal dividing plane of the steam chamber 1, together constitute the upper half-blade assembly. (See Figure 1) Figure 4 As shown, the second nozzle group 3 and the fourth nozzle group 5, located on the other side of the horizontal dividing surface of the steam chamber cavity 1, together constitute the lower half-blade assembly.

[0036] The upper half-blade assembly consists of the upper half-blade head piece, the stationary blade, and the upper half-blade tail piece welded together to form a semi-circular ring structure with a pitch circle radius of 522.1 mm. The steam passage structure of the stationary blade is described in [reference needed]. Figure 3 As shown, the number of steam passages in both sections of the first nozzle group 2 and the third nozzle group 4 is 46. The lower half-blade assembly is a semi-circular ring structure formed by welding the lower half-blade head piece, the stationary blade, and the lower half-blade tail piece. The pitch circle radius is also 522.1 mm. The steam passage structure of its stationary blade is shown in [reference needed]. Figure 5 As shown, the number of steam passages in the second nozzle group 3 and the fourth nozzle group 5 are 46 and 38, respectively.

[0037] Specifically, the first and last pieces of the upper half-blade grid are the two end pieces of the upper half-blade grid assembly, respectively. They are used to fix the end positions of the stationary blades in the upper half-blade grid assembly, ensuring the installation accuracy and uniform distribution of the stationary blades along the pitch circle. At the same time, they form a complete annular boundary of the upper half-blade grid assembly, ensuring the continuity and sealing of the steam flow channel, and providing a reliable positioning reference and welding carrier for the assembly welding of the stationary blades in the upper half-blade grid assembly. Similarly, the first and last pieces of the lower half-blade grid are the two end pieces of the lower half-blade grid assembly, respectively. They are used to fix the end positions of the stationary blades in the lower half-blade grid assembly, ensuring the installation accuracy and uniform distribution of the stationary blades along the pitch circle. At the same time, they form a complete annular boundary of the lower half-blade grid assembly, ensuring the continuity and sealing of the steam flow channel, and providing a reliable positioning reference and welding carrier for the assembly welding of the stationary blades in the lower half-blade grid assembly.

[0038] The installation angle of the stationary blades in both the upper and lower half-blade assemblies is 69°21′, the blade width is 48.39 mm, the blade height is 39 mm, and the thickness of the steam outlet edge is 0.5 mm.

[0039] Specifically, in this embodiment, the blade height of the stationary blades in the upper and lower blade assemblies is 2 mm smaller than the blade height of the moving blades on the turbine rotor. After assembly, the tip height of the moving blade is 1.5 mm higher than the tip height of the stationary blade, and the root height of the moving blade is 0.5 mm lower than the root height of the stationary blade. This ensures a continuous and regular axial flow channel between the stationary and moving blades, reduces flow disturbance and eddy current losses, improves turbine flow efficiency, and simultaneously meets the requirements for thermal expansion and assembly tolerance during turbine start-up, shutdown, and variable operating conditions.

[0040] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 6 and Figure 7 As shown, the nozzle group structure of the 600MW supercritical steam turbine suitable for deep peak shaving also includes a reinforcing ring 6; the reinforcing ring 6 is fixedly installed on the steam outlet side of the steam chamber cavity 1, and the four nozzle groups are all fixedly installed on the inner wall of the reinforcing ring 6; a steam seal structure 7 is provided on the inner wall of the reinforcing ring 6 and on the outlet side of the nozzle group, and the steam seal structure 7 and the rotor blade shroud are arranged radially opposite to each other.

[0041] In this embodiment, by fixing the reinforcing ring 6 to the steam outlet side of the steam chamber cavity 1, and fixing the four nozzle groups as a whole to the inner wall of the reinforcing ring 6, reliable circumferential positioning and axial limiting of each nozzle group can be formed, ensuring the assembly position accuracy of the nozzle group and the overall structural stability. At the same time, a steam seal structure 7 is set on the inner wall of the reinforcing ring 6 and at the outlet side of the nozzle group, so that the steam seal structure 7 and the moving blade shroud of the turbine rotor are arranged radially opposite each other. This can prevent the steam at the outlet of the nozzle group from leaking outward radially, reduce the energy loss caused by steam leakage, optimize the steam flow state, improve the overall flow efficiency of the high-pressure cylinder, and also reduce the interference of steam leakage on the operating conditions of the turbine unit, ensuring the operating stability and economic performance of the turbine unit during the load change and peak shaving process.

[0042] Among them, the reinforcing ring 6 serves as the mounting carrier for the nozzle assembly, which is used to fix the four nozzle assemblies at the outlet position of the steam chamber cavity 1 to ensure accurate positioning and structural strength that meets operational requirements.

[0043] Specifically, the reinforcing ring 6 is fixedly connected to the steam outlet side of the steam chamber 1 by welding, which is the position where the steam just comes out of the steam chamber and is about to enter the nozzle assembly.

[0044] All four nozzle groups are fixed on the inner wall of the reinforcing ring 6, forming a complete adjustable nozzle group channel.

[0045] Specifically, the four nozzle groups are arranged circumferentially and fixed to the inner wall of the reinforcing ring 6 by welding. The reinforcing ring 6 provides reliable support, positioning and structural fixation for the four nozzle groups, ensuring the positional accuracy and structural stability of the nozzle groups during operation.

[0046] Among them, the reinforcing ring 6 is provided with reinforcing ribs 61 distributed along the circumference. The reinforcing ribs 61 are used to improve the overall rigidity of the nozzle assembly and bear the steam load.

[0047] Specifically, see Figure 8 As shown, except for five steam flow channels reserved at the beginning and end positions near the upper and lower half-blade assemblies, the reinforcing ribs 61 and stationary blades at other positions on the reinforcing ring 6 are arranged in a fixed ratio. Each reinforcing rib 61 corresponds to two stationary blades, which is used to improve the overall structural rigidity of the reinforcing ring 6 and the nozzle assembly, withstand the steam force during the operation of the turbine unit, and ensure the structural stability and operational reliability of the nozzle assembly under variable operating conditions.

[0048] Among them, the reinforcing ring 6 is also equipped with a steam seal structure 7. The steam seal structure 7 and the moving blade shroud of the turbine rotor are arranged radially opposite to each other to form a radial sealing gap, which is used to prevent the steam at the nozzle group outlet from leaking out radially, reduce steam leakage loss, optimize the steam flow state, improve the turbine flow efficiency, and ensure the economy and safety of the turbine unit during deep peak shaving operation.

[0049] Specifically, the steam seal structure 7 is fixed to the inner wall of the reinforcing ring 6 by welding and is located on the outlet side of the nozzle assembly.

[0050] In the above embodiments, see Figure 7 As shown, the steam seal structure 7 includes two long-tooth steam seal baffles 71 and two short-tooth steam seal baffles 72 arranged sequentially from the outlet side of the nozzle assembly along the axial direction; the sealing tooth height of the long-tooth steam seal baffles 71 is greater than the sealing tooth height of the short-tooth steam seal baffles 72; both the long-tooth steam seal baffles 71 and the short-tooth steam seal baffles 72 are fixedly arranged on the inner wall of the reinforcing ring 6 and form a radial sealing gap with the rotor blade shroud.

[0051] It should be noted that by sequentially arranging two long-tooth steam seal plates 71 and two short-tooth steam seal plates 72 along the axial direction on the outlet side of the nozzle group, both the long-tooth steam seal plates 71 and the short-tooth steam seal plates 72 are fixed to the inner wall of the reinforcing ring 6 and form a radial sealing gap with the rotor blade shroud. This multi-stage sealing method with long and short teeth can enhance the sealing effect, prevent steam from leaking radially outward from the nozzle group outlet, reduce the energy loss caused by steam leakage, optimize the steam flow state, improve the turbine flow efficiency, and enhance the economy and operational stability of the turbine unit during deep peak shaving operation.

[0052] Among them, the steam seal structure 7 is arranged along the axial direction of the rotor on the outlet side of the nozzle group. The steam seal structure 7 is composed of two long-tooth steam seal blocking plates 71 and two short-tooth steam seal blocking plates 72 arranged in sequence. The sealing tooth height of the long-tooth steam seal blocking plate 71 is greater than the sealing tooth height of the short-tooth steam seal blocking plate 72.

[0053] Specifically, the long-tooth steam seal and the short-tooth steam seal 72 are both fixedly installed on the inner wall of the reinforcing ring 6, and form a radially opposite fit with the moving blade shroud on the rotor to form a stepped sealing structure.

[0054] In some possible implementations disclosed in this application, see [link to relevant documentation]. Figure 1 and Figure 9 As shown, the steam chamber cavity 1 is provided with a steam chamber inlet passage 1111, and a sealing ring assembly 8 is provided between the steam chamber inlet passage 11 and the turbine inlet pipe. The sealing ring assembly 8 is located between the outer wall of the turbine inlet pipe and the inner wall of the steam chamber inlet passage 11. The sealing ring assembly 8 includes a locking ring 81, a four-ring 82, a guide ring 83, and a sealing ring 84. The sealing ring 84 is used to achieve a seal between the steam chamber inlet passage 11 and the turbine inlet pipe. The guide ring 83 is used to support and guide the sealing ring 84. The four-ring 82 is used to cooperate with the locking ring 81 to axially press and position the sealing ring 84 and the guide ring 83.

[0055] In this embodiment, by setting the sealing ring assembly 8, the steam chamber inlet 11 and the turbine inlet pipe can be sealed, thereby preventing high-temperature and high-pressure steam from leaking outward from the gap between the steam chamber inlet 11 and the turbine inlet pipe, avoiding steam loss, and improving the safety and economy of the turbine unit operation.

[0056] Multiple sealing rings 84 and guide rings 83 are provided, arranged alternately along the insertion direction of the turbine inlet pipe. The circumferential length of the sealing ring 84 can change with the deformation of the inlet pipe to maintain a sealed assembly. In practical applications, the sealing rings 84 and guide rings 83 are fitted onto the outer wall of the turbine inlet pipe and arranged alternately, thereby increasing the number of sealing layers and improving the sealing effect between the turbine inlet pipe and the steam inlet passage 11 of the steam chamber, thus preventing steam leakage.

[0057] Specifically, the guide ring 83 has a stepped structure, with a first annular step formed on the side facing the outside of the turbine inlet pipe. Different steps of the first annular step are used to provide axial limiting and radial support for the sealing ring 84, ensuring that the sealing ring 84 is stably fitted between the turbine inlet pipe and the steam chamber inlet 11, ensuring that the sealing ring 84 always maintains a reliable sealing state, and improving the sealing stability and assembly adaptability of the mating position between the steam chamber inlet 11 and the turbine inlet pipe.

[0058] Among them, the locking ring 81 and the four-way ring 82 are arranged on one side of the sealing ring 84 and the guide ring 83 in the opposite direction to the insertion direction of the steam inlet pipe of the steam turbine. The locking ring 81 is used to cooperate with the four-way ring 82 to limit the locking ring 81 and the four-way ring 82 in the opposite direction to the insertion direction of the steam inlet pipe of the steam turbine.

[0059] Specifically, the locking ring 81 is also a stepped structure, with a second annular step formed on the side facing the inner wall of the steam inlet duct 11 of the steam chamber. An annular insertion groove is provided in the inner wall of the steam inlet duct 11 of the steam chamber at a position relative to the second annular step. A part of the four-ring 82 is embedded in the annular insertion groove, and the other part abuts against the second annular step.

[0060] The sealing ring assembly 8 also includes multiple pins extending radially along the turbine inlet pipe. The multiple pins are evenly arranged circumferentially along the turbine inlet pipe. One end of the pin is inserted into the locking ring 81, and the other end is connected to the steam inlet passage 11 of the steam chamber.

[0061] In the above embodiments, participants Figure 10 As shown, the sealing ring 84 has a staggered overlapping structure to form a compensating seam 841.

[0062] Specifically, the sealing ring 84 is a non-sealed circular ring with a staggered overlapping structure, forming a compensating joint 841 at the staggered overlapping point. This allows the inner diameter of the sealing ring 84 to match the outer diameter of the turbine inlet pipe. For example, when the turbine inlet pipe has a variable diameter structure, the sealing ring 84 can adaptively adjust its radial dimension through the compensating joint 841 to compensate for deviations in the turbine inlet pipe diameter and thermal expansion deformation during operation. This ensures a tight fit with the outer wall of the turbine inlet pipe, guaranteeing a stable and reliable seal under different operating conditions. This further improves the sealing effect and assembly compatibility between the steam chamber inlet duct 11 and the turbine inlet pipe.

[0063] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0064] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving, characterized in that, include: Steam chamber cavity; Four nozzle groups are evenly arranged circumferentially inside the steam chamber. The four nozzle groups are arranged symmetrically, with the plane of symmetry being the horizontal midline of the steam chamber. The number of steam passages and the steam flow area of ​​the four nozzle groups are not uniformly arranged.

2. The nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving as described in claim 1, characterized in that, The four nozzle groups include a first nozzle group, a second nozzle group, a third nozzle group, and a fourth nozzle group; The first nozzle group and the third nozzle group are located on one side of the horizontal split plane of the steam chamber cavity, and the second nozzle group and the fourth nozzle group are located on the other side of the horizontal split plane of the steam chamber cavity; The number of steam passages in the first nozzle group, the second nozzle group, and the third nozzle group is the same, and all of them have a greater number of steam passages than the fourth nozzle group.

3. The nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving as described in claim 2, characterized in that, The steam flow areas of the first nozzle group, the second nozzle group, and the third nozzle group are equal, and all are larger than the steam flow area of ​​the fourth nozzle group.

4. The nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving as described in claim 1, characterized in that, The nozzle assembly includes stationary blades with an installation angle of 69°21′, a blade width of 48.39 mm, a blade height of 39 mm, and a steam outlet edge thickness of 0.5 mm.

5. The nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving according to claim 4, characterized in that, The height of the stationary blade is 2mm smaller than that of the moving blade; The tip height of the moving blade is 1.5 mm higher than the tip height of the stationary blade; The root height of the moving blade is 0.5 mm lower than that of the stationary blade.

6. The nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving according to claim 4, characterized in that, The pitch circle radius of the nozzle assembly is 522.1 mm; the pitch circle throat dimension of the nozzle assembly is φ4.12 mm.

7. The nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving according to claim 1, characterized in that, It also includes reinforcing rings; The reinforcing ring is fixedly installed on the steam outlet side of the steam chamber, and the four nozzle groups are all fixedly installed on the inner wall of the reinforcing ring; The inner wall of the reinforcing ring and the outlet side of the nozzle assembly are provided with a steam seal structure, which is arranged radially opposite to the rotor blade shroud.

8. The nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving according to claim 7, characterized in that, The steam seal structure includes two long-tooth steam seal baffles and two short-tooth steam seal baffles arranged sequentially along the axial direction from the outlet side of the nozzle assembly. The sealing tooth height of the long-toothed steam seal barrier is greater than the sealing tooth height of the short-toothed steam seal barrier. Both the long-tooth steam seal plate and the short-tooth steam seal plate are fixedly disposed on the inner wall of the reinforcing ring, and form a radial sealing gap with the moving blade shroud of the rotor.

9. The nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving according to claim 1, characterized in that, The steam chamber cavity is provided with a steam chamber inlet passage, and a sealing ring assembly is provided between the steam chamber inlet passage and the steam turbine inlet pipe; The sealing ring assembly is located between the outer wall of the turbine inlet pipe and the inner wall of the steam chamber inlet passage. The sealing ring assembly includes a locking ring, a four-way ring, a guide ring, and a sealing ring. The sealing ring is used to achieve a seal between the steam chamber inlet and the turbine inlet pipe; The guide ring is used to support and guide the sealing ring; The four-ring is used to cooperate with the locking ring to axially press and position the sealing ring and the guide ring.

10. The nozzle assembly structure for a 600MW supercritical steam turbine suitable for deep peak shaving according to claim 9, characterized in that, The sealing ring has a staggered overlapping structure to form a compensating seam.

Images