CN110725722A - Dynamic and continuous adjustable structure for movable blade top clearance suitable for impeller machinery - Google Patents
Dynamic and continuous adjustable structure for movable blade top clearance suitable for impeller machinery Download PDFInfo
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- CN110725722A CN110725722A CN201910793849.1A CN201910793849A CN110725722A CN 110725722 A CN110725722 A CN 110725722A CN 201910793849 A CN201910793849 A CN 201910793849A CN 110725722 A CN110725722 A CN 110725722A
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- blade
- seal ring
- air seal
- teeth
- casing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
- F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
- F01D11/14—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing
- F01D11/16—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing by self-adjusting means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
- F01D11/001—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between stator blade and rotor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/24—Casings; Casing parts, e.g. diaphragms, casing fastenings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/12—Blades
- F01D5/14—Form or construction
- F01D5/20—Specially-shaped blade tips to seal space between tips and stator
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D9/00—Stators
- F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/08—Sealings
- F04D29/083—Sealings especially adapted for elastic fluid pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/26—Rotors specially for elastic fluids
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/403—Casings; Connections of working fluid especially adapted for elastic fluid pumps
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
Abstract
The invention relates to a dynamic and continuous adjustable structure of a movable blade top gap suitable for an impeller machine.A plurality of air seal teeth are arranged on an inner ring of an air seal ring, and simultaneously, the sealing function of a static blade casing and the sealing function of the movable blade top are met; the outer side of the air seal ring is provided with an axial adjusting mechanism, a blade top gap monitoring sensor and other parts, and when the impeller machinery runs, the air seal ring is controlled by the stepping motor to move along the axial direction so as to realize dynamic continuous adjustable change of the top gap of the movable blade. The sealing ring is provided with a certain number of sealing teeth with various structures, so that effective sealing of gas between the sealing ring and the stationary blade casing and between the sealing ring and the tops of the movable blades can be guaranteed, the top clearance of the movable blades can be continuously adjusted in the operation process, the impeller machinery can work under the condition of the optimal top clearance, the leakage flow of the blade tops can be reduced, the efficiency of the impeller machinery can be improved, and meanwhile, the structure is also suitable for the research of an internal flow field of the impeller machinery.
Description
Technical Field
The invention belongs to the field of impeller machinery, relates to a movable blade top clearance adjusting structure, and particularly relates to a movable blade top clearance dynamic continuous adjusting structure suitable for impeller machinery.
Background
Turbomachines are widely used in the fields of blowers, compressors, steam turbines, ground gas turbines, aircraft engines, etc., and are the main sources of electricity and various types of power. Blade top gaps exist between rotating blades (namely moving blades) and a casing in the impeller machinery, and working medium leakage at the blade top gaps of the moving blades can reduce the energy conversion efficiency of the impeller machinery, enhance the disturbance of fluid to blade tips, cause energy loss and harm the running safety of the impeller machinery. Most of moving blade top clearances of the impeller machinery are fixed values, and in order to ensure the running reliability of the impeller machinery, a designer can leave a certain margin for the actual value of the top clearance according to a theoretical calculation value, so that the running efficiency of the impeller machinery can be reduced. The invention provides a dynamic and continuously adjustable structure of the top clearance of the movable vane suitable for impeller machinery, so as to improve the reliability and the control effect of the adjustable structure of the top clearance of the movable vane.
Disclosure of Invention
Aiming at the defects and the defects in the prior art, the invention provides a movable blade top clearance dynamic continuous adjustable structure suitable for the impeller machinery, the movable blade of the impeller machinery works under the condition of the optimal top clearance through the dynamic continuous adjustment of the movable blade top clearance in the operation process, the leakage of the movable blade top can be reduced, the efficiency of the impeller machinery and the operation reliability can be improved, meanwhile, the structure is also suitable for the internal flow research of the impeller machinery, and the structure has a good application prospect.
In order to achieve the above object, the technical solution of the present invention is as follows:
a dynamic and continuously adjustable structure of blade top clearance of a movable blade suitable for an impeller machine comprises the movable blade uniformly and fixedly arranged on a main shaft along the circumferential direction, an upstream stationary blade and a downstream stationary blade which are coaxially arranged with the movable blade and are respectively positioned at the upstream and the downstream of the movable blade, and at least one air seal ring axial adjusting mechanism, wherein the blade tops of the upstream stationary blade and the downstream stationary blade are respectively and fixedly arranged on the inner walls of an annular upstream stationary blade casing and an annular downstream stationary blade casing,
an axial gap is arranged between the upstream stator blade casing and the downstream stator blade casing, the axial gap is positioned on the outer side of the blade top in the radial direction,
the outer wall edges of the upstream stationary blade casing and the downstream stationary blade casing close to the axial gap are respectively provided with a main step surface, each main step surface is provided with a sealing tooth arranged along the circumferential direction,
an air seal ring extending along the axial direction is arranged between the two opposite main step surfaces, an annular bulge is formed on the inner wall of the air seal ring, first seal teeth arranged along the circumferential direction are arranged on the annular bulge, and second seal teeth arranged along the circumferential direction are arranged on the inner wall of the air seal ring which is axially positioned at the two sides of the annular bulge;
the movable blade tip is provided with a blade crown, and a meridian plane molded line of the blade crown is in a slope or step shape and is used for being matched with the first sealing tooth to form a movable blade tip gas seal;
second seal teeth positioned at the upstream of the first seal teeth and seal teeth on a main step surface of the upstream stator blade casing are arranged in a staggered mode to form a high-pressure side stator blade outer ring seal;
second seal teeth positioned at the downstream of the first seal teeth and seal teeth on a main step surface of the downstream stator blade casing are arranged in a staggered mode to form a low-pressure side stator blade outer ring seal;
the axial adjusting mechanism of the air seal ring comprises a lead screw or a rack, a nut matched with the lead screw or a gear matched with the rack, a stepping motor, at least one blade top gap monitoring sensor and a control unit, wherein,
the screw rod or the rack extends along the axial direction, and two ends of the screw rod or the rack are fixedly supported on the outer walls of the upstream stationary blade casing and the downstream stationary blade casing through a positioning support respectively;
the nut or the gear is arranged on the air seal ring through a base of the nut or the gear, and the stepping motor is arranged on the base of the nut or the gear and is in transmission connection with the nut or the gear;
the blade top clearance monitoring sensor is fixedly arranged on the annular bulge of the air seal ring and used for dynamically measuring the blade top clearance between the first seal tooth on the annular bulge and the blade crown on the blade top of the movable blade in real time;
the stepping motor and the blade top gap monitoring sensor are in communication connection with the control unit, blade top gap information collected by the blade top gap monitoring sensor is transmitted to the control unit, the control unit controls the stepping motor to rotate according to the blade top gap information, and then dynamic continuous adjustment of the blade top gap of the movable blade is achieved by adjusting axial movement of the air seal ring.
Preferably, shaft seals are arranged between blade roots of the upstream stationary blade and the downstream stationary blade and the main shaft.
Preferably, the annular protrusion on the inner wall of the gas seal ring and the shroud on the top of the movable blade are both partially protruded into the axial gap.
Preferably, a width of the gas seal ring in the axial direction is smaller than a width between main step faces of the upstream and downstream vane casings, and a width of the annular protrusion in the axial direction is smaller than a width of the axial gap, so that the gas seal ring has a space to move in the axial direction.
Preferably, the inner walls of the two ends of the gas seal ring are also formed into stepped surface structures, the main stepped surfaces of the upstream stationary blade casing and the downstream stationary blade casing are respectively provided with a secondary stepped surface matched with the stepped surface on the inner wall of the gas seal ring, and when the gas seal ring moves axially, the stepped surfaces on the inner walls of the two ends of the gas seal ring are overlapped on the secondary stepped surfaces to form surface sealing.
Preferably, the second seal tooth disposed on the inner wall of the gas seal ring, the first seal tooth disposed on the annular protrusion, and the seal teeth disposed on the step surfaces of the upstream stationary blade casing and the downstream stationary blade casing are all disposed by means of embedding or welding, and the seal teeth at each position are in the form of comb teeth, fir-tree teeth, J-type gas seals, honeycomb seal teeth, or brush seal teeth.
In the structure with the dynamic and continuously adjustable gap between the top of the movable blade and the top of the movable blade suitable for the impeller machinery, the air seal ring is mainly used for effectively sealing the gas flowing between the air seal ring and the step surface on the outer wall of the stationary blade casing and between the air seal ring and the top of the movable blade, a certain number of seal teeth are arranged on the inner wall of the air seal ring, a certain number of seal teeth are arranged on the step surface on the outer wall of the stationary blade casing, and the step surface on the outer wall of the stationary blade casing and the seal teeth on the inner wall of the air seal ring are arranged in a staggered mode and are used for fluid sealing at the corresponding position. The sealing teeth mainly have a sealing function, but also have a certain auxiliary supporting function. The length of the sealing section and the design of the sealing teeth are designed according to the pressure class.
Preferably, the bottom of each positioning support is provided with an adjusting block, the concentricity of the air seal ring with the upstream stationary blade casing, the downstream stationary blade casing and the main shaft is adjusted by adjusting the thickness of the adjusting block, and the axial movement of the air seal ring is realized by controlling the axial position of the nut or the gear on the screw rod or the rack.
Preferably, the lead screw and the stepping motor have the advantages of light weight, low cost and high positioning precision, so that the axial adjustment mechanism of the air seal ring disclosed by the invention realizes the axial movement of the air seal ring in a mode that the lead screw and the stepping motor are matched with each other. After the assembly is completed, the relative position between the gas seal ring and the static part needs to be calibrated and is used as an input parameter for controlling the blade top clearance in the operation process of the impeller machine. Cushion blocks below the positioning supports at the two ends of the lead screw can adjust the coaxiality of the air seal ring and the rotor. The direction of rotation of lead screw is equipped with lead screw positioning bolt, and the keyway has been seted up to the correspondence on the surface of lead screw, and the keyway has certain length along the axial, guarantees to be adjustable, and after whole regulations, must carry out the axial spacing. Preferably, the two sides of the positioning support at the two ends of the screw rod along the circumferential direction are provided with fastening bolts so as to save the axial length of the whole mechanical structure. In the axial adjusting mechanism of the air seal ring, the thrust generated by the stepping motor during operation is larger than the sum of the maximum axial thrust borne by the air seal ring and the friction force of the contact between the seal teeth and the static part, so that the air seal ring can move smoothly along the axial direction.
Preferably, a plurality of blade tip clearance monitoring sensors are uniformly arranged on the annular bulge of the air seal ring along the circumferential direction of the annular bulge, each blade tip clearance monitoring sensor is in communication connection with the control unit, and the control unit judges the eccentricity of the air seal ring relative to the main shaft according to blade tip clearance information acquired by the plurality of blade tip clearance monitoring sensors.
In the structure suitable for dynamically and continuously adjusting the movable blade tip clearance of the impeller machinery, the tip clearance monitoring sensor is used for measuring the tip clearance between the sealing teeth on the annular bulge on the inner wall of the air seal ring and the movable blade tip shroud, a plurality of tip clearance monitoring sensors are arranged all around to calculate the eccentricity condition, and relevant data are fed back to the measurement and control unit for analysis and control.
Preferably, the impeller machine is a compressor, the blade tips of the moving blades are not provided with a blade crown, the annular bulge of the air seal ring is not provided with a first seal tooth, and the annular bulge is formed into a conical ring with the same inclination as that of the blade tips of the moving blades. Because the blade top of the compressor is not provided with the blade crown generally, when the sealing structure of the blade top of the compressor is applied, the annular bulge corresponding to the blade top is set to be a conical ring with the same inclination as the blade top.
Preferably, a pneumatic parameter measuring sensor is further arranged on the air seal ring, and the pneumatic parameter measuring sensor is arranged between each movable blade row or between the seal teeth and the blade rows and moves along with the air seal ring along the axial direction.
Preferably, the air seal ring is of an integral cylindrical structure or a split structure which is split at a middle split surface and connected by a fastener, and the thickness and the axial length of the air seal ring are determined according to the pressure difference and the temperature of the inner leakage position and the outer leakage position.
According to another aspect of the invention, the impeller machine is characterized in that the impeller machine is provided with the structure which is provided with the dynamic and continuously adjustable top clearance of the movable blades suitable for the impeller machine.
The structure for dynamically and continuously adjusting the movable vane top clearance suitable for the impeller machinery has the advantages that the movable vane top clearance can be adjusted within a certain range, the running efficiency of the impeller machinery can be improved to the maximum extent, an axial limiting and concentricity adjusting scheme is designed, the practicability of machining, assembling and running is good, and the structure is also suitable for relevant researches on clearance leakage characteristics and influences on rotor dynamics and the like.
Compared with the prior art, the invention has the advantages and beneficial effects that:
1. the movable blade top clearance dynamic continuous adjustable structure suitable for the impeller machinery enables the movable blade of the impeller machinery to work under the condition of the optimal blade top clearance through the dynamic continuous adjustment of the movable blade top clearance in the operation process, can reduce the leakage of the movable blade top, and improve the efficiency and the operation reliability of the impeller machinery, and is also suitable for the internal flow research of the impeller machinery.
2. Compared with the existing air pressure and spring combined structure, the air seal ring moves axially under the control of the axial adjusting mechanism of the air seal ring, the control precision, the repeated positioning precision and the reliability are higher, the reaction is sensitive, and the control process has no lag or overshoot phenomenon.
3. Compared with a blade top gap adjustable structure of a sheet corrugated pipe or a spring piece casing, the air seal ring adopted by the invention has good rigidity, can bear larger pressure difference, cannot generate non-uniform deformation due to non-uniform circumferential distribution of internal air pressure, and cannot generate plastic deformation after long-term operation.
Drawings
FIG. 1 is a schematic view of a dynamic and continuously adjustable structure of a bucket tip clearance for a turbomachine;
FIG. 2 is an enlarged view of a portion of gaps a-c of FIG. 1;
FIG. 3 is a partial enlarged view of the gaps d-i in FIG. 1.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and examples.
Embodiments of the present invention are shown in FIGS. 1 to 3. Fig. 1 is a schematic diagram of an overall structure of a dynamic and continuously adjustable structure of a blade top gap of a movable blade suitable for an impeller machine according to the present invention, and the dynamic and continuously adjustable structure of the blade top gap of the movable blade mainly comprises a main shaft 1, a movable blade 2, a stationary blade casing 3, a shaft seal 4, a high-pressure side stationary blade outer ring seal 5, a blade shroud 6, a movable blade top air seal 7, a low-pressure side stationary blade outer ring seal 8, an air seal ring 9, a lead screw 10, a stepping motor 11, a positioning support 12, a blade top gap monitoring sensor 13, a lead screw positioning bolt 14, a lead screw locking nut 15, and the like, wherein R represents a rotor movable blade, and S represents a stationary blade. After the concentricity of the screw 10 is adjusted, the screw is limited by double nuts beside the positioning support 12, or a single nut is adopted to add a flat cushion and an elastic cushion. Specifically, the structure for dynamically and continuously adjusting the blade tip clearance of the movable blade applicable to the impeller machinery comprises the movable blade 2 uniformly and fixedly arranged on the main shaft 1 along the circumferential direction, the upstream stationary blade 3 and the downstream stationary blade 3 which are coaxially arranged with the movable blade 2 and are respectively positioned at the upstream and the downstream of the movable blade 2, and at least one air seal ring axial adjusting mechanism, wherein the blade tips of the upstream stationary blade 3 and the downstream stationary blade 3 are respectively and fixedly arranged on the inner walls of an annular upstream stationary blade casing 16 and an annular downstream stationary blade casing 16, and shaft seals 4 are respectively arranged between the upstream stationary blade 3, the downstream stationary blade 3 and the main shaft 1. An axial gap is formed between the upstream stationary blade casing 16 and the downstream stationary blade casing 16, and the axial gap is located outside the blade tip of the movable blade 2 in the circumferential direction; step surfaces are formed on the outer wall edges of the upstream stationary blade casing 16 and the downstream stationary blade casing 16 close to the axial gap, and each step surface is provided with a sealing tooth arranged along the circumferential direction; an air seal ring 9 extending along the axial direction is arranged between the two opposite step surfaces, an annular bulge is formed on the inner wall of the air seal ring 9, first seal teeth arranged along the circumferential direction are arranged on the annular bulge, and second seal teeth arranged along the circumferential direction are arranged on the inner wall of the air seal ring positioned on the two sides of the annular bulge in the axial direction; the movable blade tip is provided with a blade crown 6, the meridian plane molded line of the blade crown 6 is in a slope or step shape and is used for being matched with the first sealing tooth to form a movable blade tip air seal 7, and the annular bulge on the inner wall of the air seal ring 9 and the blade crown 6 on the movable blade tip both partially extend into the axial gap; the second seal teeth positioned at the upstream of the first seal teeth and the seal teeth on the step surface of the upstream stator blade casing 16 are staggered to form a high-pressure side stator blade outer ring seal 5; the second seal teeth positioned at the downstream of the first seal teeth and the seal teeth on the step surface of the downstream stator blade casing 16 are staggered to form a low-pressure side stator blade outer ring seal 8; the width of the gas seal ring 9 in the axial direction is smaller than the width between the main step surfaces of the upstream stationary blade casing 16 and the downstream stationary blade casing 16, and the width of the annular protrusion in the axial direction is smaller than the width of the axial gap, so that the gas seal ring 9 has a space for moving in the axial direction; the inner walls of two ends of the gas seal ring 9 are also formed into stepped surface structures, secondary stepped surfaces matched with the stepped surfaces on the inner wall of the gas seal ring 9 are respectively formed on the main stepped surfaces of the upstream stationary blade casing 16 and the downstream stationary blade casing 16, and when the gas seal ring 9 moves axially, the stepped surfaces on the inner walls of the two ends of the gas seal ring are overlapped on the secondary stepped surfaces to form surface sealing. The axial adjusting mechanism of the air seal ring comprises a lead screw, a nut matched with the lead screw for use, a stepping motor 11, at least one blade top gap monitoring sensor 13 and a control unit, wherein the lead screw 10 extends along the axial direction, and two ends of the lead screw are fixedly supported on the outer walls of an upstream stationary blade casing 16 and a downstream stationary blade casing 16 through a positioning support 12 respectively; the nut is arranged on the air seal ring 9 through a base, and the stepping motor 11 is arranged on the base of the nut and is in transmission connection with the nut; the blade top gap monitoring sensor 13 is fixedly arranged on the annular bulge of the gas seal ring 9 and used for dynamically measuring the blade top gap between the first seal tooth on the annular bulge and the blade crown on the blade top of the movable blade in real time; the stepping motor 11 and the blade top gap monitoring sensor 13 are in communication connection with the control unit, blade top gap information collected by the blade top gap monitoring sensor 13 is transmitted to the control unit, the control unit controls the stepping motor 11 to rotate according to the blade top gap information, and then dynamic continuous adjustment of the blade top gap of the movable blade is achieved by adjusting the left-right movement of the air seal ring 9.
In the above structure, the gas seal ring 9 is mainly used for effectively sealing the gas flow between the gas seal ring and the outer wall of the stationary blade casing and between the gas seal ring and the top of the movable blade, a certain number of seal teeth are embedded in the inner ring of the gas seal ring, a certain number of seal teeth are embedded in the outer ring of the stationary blade ring, and the seal teeth of the outer ring of the stationary blade ring and the inner ring of the gas seal ring are arranged in a staggered manner and used for fluid sealing at corresponding positions. The sealing teeth mainly have a sealing function, but also have a certain auxiliary supporting function. The length of the sealing section and the design of the sealing teeth are designed according to the pressure class.
Further, the second seal tooth provided on the inner wall of the gas seal ring 9, the first seal tooth provided on the annular projection, and the seal teeth provided on the step surfaces of the upstream stationary blade casing 16 and the downstream stationary blade casing 16 are all provided by means of insert or welding, and the seal teeth at each position are structured in the form of comb teeth, fir-tree teeth, J-type gas seals, honeycomb seal teeth, or brush seal teeth. Because the lead screw and the stepping motor have the advantages of light weight, low cost and high positioning precision, the axial adjusting mechanism of the air seal ring disclosed by the invention realizes the axial movement of the air seal ring by preferably selecting a mode of mutually matching the lead screw and the stepping motor. After the assembly is completed, the relative position between the gas seal ring and the static part needs to be calibrated and is used as an input parameter for controlling the blade top clearance in the operation process of the impeller machine. The cushion blocks below the positioning supports 12 at the two ends of the screw rod can adjust the coaxiality of the air seal ring and the rotor. The rotation direction of lead screw 10 is equipped with lead screw positioning bolt 14, and the keyway has been seted up on the correspondence of lead screw 10 on the surface, and the keyway has certain length along the axial, guarantees to be adjustable, and after whole regulations, must carry out the axial spacing. Preferably, the positioning supports 12 at both ends of the screw are provided with fastening bolts at both sides in the circumferential direction to save the axial length of the whole mechanical structure. In the axial adjusting mechanism of the air seal ring, the thrust generated by the stepping motor during operation is larger than the sum of the maximum axial thrust borne by the air seal ring and the friction force of the contact between the seal teeth and the static part, so that the air seal ring can move smoothly along the axial direction. In addition, a plurality of blade top gap monitoring sensors 13 are uniformly arranged on the annular bulge of the gas seal ring 9 along the circumferential direction of the annular bulge, each blade top gap monitoring sensor 13 is in communication connection with the control unit, the control unit judges the eccentricity of the gas seal ring relative to the main shaft 1 through blade top gap information acquired by the plurality of blade top gap monitoring sensors 13, and relevant data are fed back to the measurement and control unit for analysis and control. The air seal ring 9 can also be provided with a pneumatic parameter measuring sensor which is arranged between the movable blade rows or between the seal teeth and the blade rows and moves along the axial direction along with the air seal ring.
It should be noted that, because the blade tip of the compressor generally does not have a blade tip shroud, when the sealing structure of the blade tip of the compressor is applied, the annular protrusion corresponding to the top of the movable blade is only required to be a conical ring with the same inclination as the blade tip.
In addition, the gas seal ring 9 is an integral cylindrical structure or a split structure which is split at a middle surface and is connected by a fastener, and the thickness and the axial length of the gas seal ring are determined according to the pressure difference and the temperature of the inner and outer leakage positions.
The second seal tooth arranged on the inner wall of the air seal ring, the first seal tooth arranged on the annular bulge and the seal teeth arranged on the step surfaces of the upstream stator blade casing 16 and the downstream stator blade casing 16 are all arranged in an embedding or welding mode, and the seal teeth at each position are in the structural form of comb teeth, fir-tree teeth, J-shaped air seals, honeycomb seal teeth or brush seal teeth. In fig. 2 and 3, the value of the J-shaped air seal gap a is 0-0.02 mm, the inner wall of the air seal ring can contact with the top of the J-shaped air seal on the step surface of the stationary blade casing to play a certain supporting role, and the value of the sharp tooth air seal gap b is 0.02-0.05 mm. The top of the movable blade in the figure shows two sealing structures, namely a step structure and a high-low step structure, wherein the step is arranged into an inclined surface. The gaps c, d and e near the blade crown are designed to be limited, values are taken according to the length of the air seal ring allowed to move along the axial direction, the influence of misoperation on the running safety of the impeller machine is avoided, the current blade top gap condition can be obtained through the size of the axial relative position c or d of the air seal ring and the static part, and the initial value is recorded. f is the radial clearance of the inclined plane of the blade shroud, and when the air seal ring moves to the right side in the graphs 2 and 3, the air seal clearance of the blade shroud is reduced, and when the air seal ring moves to the left side, the air seal clearance is increased. The clearance g is the distance between the gas seal tooth and the step of the blade shroud, the clearances h and i are the axial distances between the fir-tree gas seal tooth and the blade shroud, and the smaller the values of h and i are for the side tooth of the fir-tree tooth, the better the blade tip sealing effect is, so that the movement of the gas seal ring needs to be controlled according to the design value and the actual measurement value, and the leakage amount of the equipment is minimized.
The object of the patent is fully effectively achieved by the above embodiments. One skilled in the art will appreciate that this patent includes, but is not limited to, the figures and the description of the specific embodiments above. While this patent has been described in terms of what are presently considered to be practical and preferred embodiments, it is to be understood that the patent is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications within the scope of the appended claims.
Claims (10)
1. A dynamic and continuously adjustable structure of blade top clearance of a movable blade suitable for an impeller machine comprises the movable blade uniformly and fixedly arranged on a main shaft along the circumferential direction, an upstream stationary blade and a downstream stationary blade which are coaxially arranged with the movable blade and are respectively positioned at the upstream and the downstream of the movable blade, and at least one air seal ring axial adjusting mechanism, wherein the blade tops of the upstream stationary blade and the downstream stationary blade are respectively and fixedly arranged on the inner walls of an annular upstream stationary blade casing and an annular downstream stationary blade casing,
an axial gap is arranged between the upstream stator blade casing and the downstream stator blade casing, the axial gap is positioned on the outer side of the blade top in the radial direction,
the outer wall edges of the upstream stationary blade casing and the downstream stationary blade casing close to the axial gap are respectively provided with a main step surface, each main step surface is provided with a sealing tooth arranged along the circumferential direction,
an air seal ring extending along the axial direction is arranged between the two opposite main step surfaces, an annular bulge is formed on the inner wall of the air seal ring, first seal teeth arranged along the circumferential direction are arranged on the annular bulge, and second seal teeth arranged along the circumferential direction are arranged on the inner wall of the air seal ring which is axially positioned at the two sides of the annular bulge;
the movable blade tip is provided with a blade crown, and a meridian plane molded line of the blade crown is in a slope or step shape and is used for being matched with the first sealing tooth to form a movable blade tip gas seal;
second seal teeth positioned at the upstream of the first seal teeth and seal teeth on a main step surface of the upstream stator blade casing are arranged in a staggered mode to form a high-pressure side stator blade outer ring seal;
second seal teeth positioned at the downstream of the first seal teeth and seal teeth on a main step surface of the downstream stator blade casing are arranged in a staggered mode to form a low-pressure side stator blade outer ring seal;
the axial adjusting mechanism of the air seal ring comprises a lead screw or a rack, a nut matched with the lead screw or a gear matched with the rack, a stepping motor, at least one blade top gap monitoring sensor and a control unit, wherein,
the screw rod or the rack extends along the axial direction, and two ends of the screw rod or the rack are fixedly supported on the outer walls of the upstream stationary blade casing and the downstream stationary blade casing through a positioning support respectively;
the nut or the gear is arranged on the air seal ring through a base of the nut or the gear, and the stepping motor is arranged on the base of the nut or the gear and is in transmission connection with the nut or the gear;
the blade top clearance monitoring sensor is fixedly arranged on the annular bulge of the air seal ring and used for dynamically measuring the blade top clearance between the first seal tooth on the annular bulge and the blade crown on the blade top of the movable blade in real time;
the stepping motor and the blade top gap monitoring sensor are in communication connection with the control unit, blade top gap information collected by the blade top gap monitoring sensor is transmitted to the control unit, the control unit controls the stepping motor to rotate according to the blade top gap information, and then dynamic continuous adjustment of the blade top gap of the movable blade is achieved by adjusting axial movement of the air seal ring.
2. The structure of claim, wherein shaft seals are disposed between the blade roots of the upstream and downstream stationary blades and the main shaft.
3. The structure of the dynamic and continuous adjustable gap between the top of the movable vane and the top of the movable vane suitable for the impeller machine as claimed in the preceding claim, wherein the annular protrusion on the inner wall of the air seal ring and the tip shroud on the top of the movable vane partially protrude into the axial gap.
4. The structure of dynamic and continuously adjustable blade tip clearance for an impeller machine as claimed in the preceding claim, wherein the width of the gas seal ring in the axial direction is smaller than the width between the main step surfaces of the upstream and downstream stationary blade casings, and the width of the annular protrusion in the axial direction is smaller than the width of the axial clearance, so that the gas seal ring has a space to move in the axial direction.
5. The structure as claimed in any preceding claim, wherein the dynamic and continuously adjustable tip clearance of the movable blade for the turbomachine is further configured to have a stepped surface structure on inner walls of both ends of the air seal ring, and the main stepped surfaces of the upstream stationary blade casing and the downstream stationary blade casing are respectively formed with a secondary stepped surface that is engaged with the stepped surface on the inner wall of the air seal ring, and when the air seal ring moves axially, the stepped surfaces on the inner walls of both ends of the air seal ring overlap with the secondary stepped surface to form a surface seal.
6. The dynamic and continuously adjustable structure for the tip clearance of the movable blade suitable for the impeller machine according to the above claims, wherein the second seal tooth provided on the inner wall of the seal ring, the first seal tooth provided on the annular protrusion, and the seal teeth provided on the step surfaces of the upstream stationary blade casing and the downstream stationary blade casing are all provided by means of embedding or welding, and the seal teeth at each position are in the form of comb teeth, fir-tree teeth, J-type seals, honeycomb seal teeth, or brush seal teeth.
7. The structure as claimed in the preceding claim, wherein the bottom of each positioning support is provided with an adjusting block, the concentricity of the air seal ring with the upstream stationary blade casing, the downstream stationary blade casing and the main shaft is adjusted by adjusting the thickness of the adjusting block, and the axial movement of the air seal ring is realized by controlling the axial position of the nut or the gear on the screw or the rack.
8. The structure of claim, wherein the annular protrusion of the air seal ring is uniformly provided with a plurality of blade tip clearance monitoring sensors along a circumferential direction thereof, each blade tip clearance monitoring sensor is in communication connection with the control unit, and the control unit determines an eccentricity of the air seal ring relative to the main shaft according to blade tip clearance information collected by the plurality of blade tip clearance monitoring sensors.
9. The structure of dynamic and continuous adjustable gap between blade tips of moving blades suitable for impeller machinery as claimed in the preceding claim, wherein the impeller machinery is a compressor, the blade tips of the moving blades are not provided with a tip shroud, the annular protrusion of the air seal ring is not provided with the first seal tooth, and the annular protrusion is formed into a tapered circular ring with the same pitch as that of the blade tips of the moving blades. Preferably, the air seal ring is of an integral cylindrical structure or a split structure which is split at a middle split surface and connected by a fastener.
10. A turbo machine, characterized in that the structure of any preceding claim is arranged in the turbo machine, and the structure is suitable for a turbo machine, and the dynamic and continuous gap between the top of the moving blades is adjustable.
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| CN201910793849.1A CN110725722B (en) | 2019-08-27 | 2019-08-27 | Dynamic and continuous adjustable structure for movable blade top clearance suitable for impeller machinery |
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| CN201910793849.1A CN110725722B (en) | 2019-08-27 | 2019-08-27 | Dynamic and continuous adjustable structure for movable blade top clearance suitable for impeller machinery |
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| CN110725722B (en) | 2022-04-19 |
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