CN114151547A - Rotary-resisting vibration-damping sealing structure of supercritical carbon dioxide rotary machine - Google Patents
Rotary-resisting vibration-damping sealing structure of supercritical carbon dioxide rotary machine Download PDFInfo
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- CN114151547A CN114151547A CN202210009743.XA CN202210009743A CN114151547A CN 114151547 A CN114151547 A CN 114151547A CN 202210009743 A CN202210009743 A CN 202210009743A CN 114151547 A CN114151547 A CN 114151547A
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- sealing ring
- rotation
- carbon dioxide
- supercritical carbon
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/44—Free-space packings
- F16J15/447—Labyrinth packings
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
Abstract
The invention discloses a rotation-resisting vibration-reducing sealing structure of a supercritical carbon dioxide rotating machine, which reduces the sealing leakage amount and the circumferential speed of sealing airflow and comprises a shell and a main shaft, wherein the main shaft is provided with a rotation-resisting sealing ring, a ventilating sealing ring and a low-pressure sealing ring; the inner circular surface of the ventilation sealing ring is provided with a rotation blocking cavity along the circumferential direction, the ventilation sealing ring is provided with a plurality of nozzle holes, the shell is provided with a shell air inlet hole, the shell air inlet hole is communicated with all the nozzle holes through an annular groove formed in the shell and is used for spraying rotation blocking air into the rotation blocking cavity through the shell air inlet hole and the nozzle holes, the flow direction of the rotation blocking air is opposite to the rotation direction of the main shaft, the circumferential air speed in the rotation blocking cavity is reduced, and the circumferential pressure in the rotation blocking cavity is uniformly distributed.
Description
Technical Field
The invention relates to the technical field of supercritical carbon dioxide rotating machinery, in particular to a rotation-resisting vibration-reducing sealing structure of supercritical carbon dioxide rotating machinery.
Background
The sealing element is a key part in the rotary machine, can reduce the leakage of the rotary machine fluid, and along with the increase of the rotary machine rotating speed and the medium pressure, the increase of the rotor flexibility and the reduction of the sealing clearance, the fluid excitation in the sealing cavity can cause the rotor to vibrate strongly and even be unstable. Research shows that seal gas loss stability is mainly caused by cross rigidity generated by circumferential velocity of fluid in the seal. The circumferential velocity of the fluid inside the seal is mainly generated by two aspects: one is that the fluid has a large inlet pre-swirl velocity before entering the seal: and the sealed inner fluid is driven by the viscous friction of the rotating rotor to flow in the circumferential direction. The fluid flows in the circumferential direction of the sealing gap, so that the circumferential pressure of the fluid in the sealing gap is uneven, air loss stability force is generated by uneven pressure distribution, and further, cross rigidity is generated to cause sealing instability.
The supercritical carbon dioxide rotary machine mainly comprises a supercritical carbon dioxide compressor and a turbine, and has the advantages of high rotating speed, long and thin shaft system, high medium pressure, high temperature and high density. Taking a 10MW turbine compression all-in-one machine as an example, the working rotation speed is 27000rpm, the journal size is 76mm, the bearing span is 914mm, the pressure is 8-25 MPa, the temperature is up to 715 ℃, the pressure difference between two ends of a sealing body in the machine set is high, in order to reduce the sealing leakage amount and save the axial arrangement space, a combined sealing form of carbon ring and labyrinth seal is generally adopted, the circumferential speed of a rotor is high, the carbon ring sealing gap is small and is generally smaller than 0.1mm, and the excitation caused when the supercritical carbon dioxide flows at the sealing gap is more severe.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a rotation-resisting vibration-reducing sealing structure of a supercritical carbon dioxide rotating machine, which reduces the circumferential speed of sealing airflow while ensuring that the leakage amount of sealing is reduced, thereby reducing the cross-coupling rigidity of sealing and preventing the phenomena of large vibration and even instability of a rotor caused by sealing excitation.
The purpose of the invention is realized as follows:
a rotary-resisting vibration-damping sealing structure of supercritical carbon dioxide rotary machinery comprises a shell and a main shaft,
the main shaft is sequentially sleeved with a rotation-resistant sealing ring, a ventilating sealing ring and a low-pressure sealing ring from a high-pressure side to a low-pressure side, the ventilating sealing ring is fixedly arranged on the shell, the ventilating sealing ring is respectively and fixedly connected with the rotation-resistant sealing ring and the low-pressure sealing ring, and labyrinth sealing teeth are respectively arranged on the inner circular surfaces of the rotation-resistant sealing ring and the low-pressure sealing ring;
the inner circular surface of the ventilation sealing ring is provided with a rotation blocking cavity along the circumferential direction, the ventilation sealing ring is provided with a plurality of nozzle holes, the plurality of nozzle holes are uniformly distributed along the circumferential direction of the ventilation sealing ring, each nozzle hole extends along the tangential direction of the main shaft, the shell is provided with a shell air inlet hole, the shell air inlet hole is communicated with all the nozzle holes through an annular groove formed in the shell and is used for spraying rotation blocking air into the rotation blocking cavity through the shell air inlet hole and the nozzle holes, the flow direction of the rotation blocking air is opposite to the rotation direction of the main shaft and is used for reducing the circumferential air flow velocity in the rotation blocking cavity and enabling the circumferential pressure in the rotation blocking cavity to be uniformly distributed.
Preferably, the supercritical carbon dioxide rotary machine includes a supercritical carbon dioxide compressor, a supercritical carbon dioxide turbine.
Preferably, labyrinth seal teeth are respectively arranged at two ends of the inner circular surface of the ventilating seal ring, and the rotation-resisting cavity is formed between the labyrinth seal teeth.
Preferably, the rotation-resisting sealing ring and the low-pressure sealing ring are installed on the ventilation sealing ring in a matched mode through hole shafts and are fixed through screws.
Preferably, the high-pressure side of the rotation-resisting sealing ring is provided with a plurality of rotation-resisting grids which are uniformly distributed along the circumferential direction of the rotation-resisting sealing ring, and when the supercritical carbon dioxide medium enters the rotation-resisting sealing ring from the high-pressure side, the rotation-resisting grids are used for breaking the rotational flow of the supercritical carbon dioxide medium in the circumferential direction and reducing the inlet pre-rotation speed when entering the labyrinth sealing teeth of the rotation-resisting sealing ring.
Preferably, be equipped with respectively between the sealing ring of ventilating and the rotation-resisting sealing ring, the low pressure sealing ring and be annular mounting groove, be equipped with three lamella formula carbocycles in each mounting groove respectively, three lamella formula carbocycles are cramped through extension spring, make three lamella formula carbocycles embrace on the main shaft, and three lamella formula carbocycles are through stop pin circumference location.
Preferably, the peripheral surface of the three-petal carbon ring is an inclined surface, and the extension spring is matched with the rotation-resisting sealing ring/the low-pressure sealing ring, so that the three-petal carbon ring axially abuts against the end surface of the rotation-resisting sealing ring/the ventilating sealing ring, and the carbon ring small-gap sealing is formed.
Preferably, the shell air inlet is connected with a high-pressure storage tank of the supercritical carbon dioxide power generation system through an air inlet pipeline, the air inlet pipeline is provided with a flow regulating valve, the spindle is provided with a rotating speed sensor, the rotating speed sensor and the flow regulating valve are in signal connection with a PLC (programmable logic controller), and the PLC is used for controlling air inflow according to the rotating speed of the spindle.
Preferably, simulation calculation is performed according to the relation between the rotating speed of the main shaft and the flow velocity of the nozzle hole to obtain the relation between the rotating speed of the main shaft and the air inflow, and the PLC sets a control algorithm of the flow regulating valve according to the relation between the rotating speed of the main shaft and the air inflow.
By adopting the technical scheme, the invention reduces the circumferential speed of the sealing air flow while ensuring that the sealing leakage is reduced, thereby reducing the cross coupling rigidity of the seal and preventing the phenomenon of large vibration and even instability of the rotor caused by the vibration excitation of the seal.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic view of the structure of the cyclone;
fig. 3 is a schematic structural diagram of a rotation-blocking gate.
Reference numerals
In the attached drawings, 1 is a rotation-resisting sealing ring; 1-rotation-resisting grid; 2, elastic cushion; 3-screws; 4, an anti-rotation pin; 5-a three-membered carbocyclic ring; 6, an extension spring; 7-ventilating sealing ring; 7-1-nozzle orifice; 7-2-rotation-resisting cavity; 8, an anti-rotation pin; 9-a three-membered carbocyclic ring; 10-extension spring; 11-spring pad; 12-a screw; 13-low pressure seal ring; 14-a housing; 14-1 — housing inlet port; 15-an air inlet pipeline; 16-flow regulating valve; 17-a high-pressure storage tank; 18-a rotational speed sensor; 19. 21-signal line; 22-main shaft.
Detailed Description
Referring to fig. 1-3, the rotary-resisting vibration-damping sealing structure of the supercritical carbon dioxide rotary machine comprises a rotary-resisting sealing ring 1 provided with labyrinth sealing teeth, the rotary-resisting sealing ring is installed on a ventilating sealing ring 7 in a matched mode through a hole shaft and is compressed through an elastic cushion 2 and a screw 3, a circle of uniformly-distributed rotary-resisting grids 1-1 are arranged on the front portion of the rotary-resisting sealing ring 1, when a supercritical carbon dioxide medium enters the rotary-resisting sealing ring 1 from a high-pressure side, the rotary-resisting grids 1-1 can break the rotary flow in the circumferential direction of the rotary-resisting sealing ring, and the inlet prerotation speed when the rotary-resisting sealing ring enters the sealing ring is reduced.
Three lamella formula carbocycles 5 are cramped through 6 circumference of extension spring to rely on inclined plane and the terminal surface of the sealing ring 7 of ventilating on the three lamella formula carbocycle 5, support 5 axial of three lamella formula carbocycles tightly on hindering the terminal surface of rotary seal ring 1, and set up stop pin 4 and prevent that three lamella formula carbocycles 5 from rotating, make supercritical carbon dioxide medium can only pass through from the radial little clearance of three lamella formula carbocycles 5 and main shaft 22, can not reveal from the terminal surface, reduce the volume of revealing.
The ventilating seal ring 7 is arranged on the shell 14, labyrinth seal teeth are arranged on the left side and the right side of the inside of the ventilating seal ring, the rotation-resistant cavity 7-2 is arranged in the middle of the inside of the ventilating seal ring, the rotation-resistant cavity 7-2 is connected with an air inlet 14-1 on the shell 14 through a circle of nozzle holes 7-1, the rotation direction of the nozzle holes 7-1 when the rotation-resistant air is introduced into the rotation-resistant air is opposite to the rotation direction of the main shaft, the whole circle of the nozzle holes is required to be uniformly distributed, the more the number of the nozzle holes is within a structural allowable range, and the ventilating seal ring is favorable for reducing the circumferential air flow speed in the rotation-resistant cavity 7-2 and uniformly distributing the circumferential pressure in the rotation-resistant cavity 7-2.
Be provided with the low pressure sealing ring 13 of labyrinth seal tooth, install on ventilating sealing ring 7 through the hole axle cooperation, and compress tightly through bullet pad 11 and screw 12, three lamella formula carbocycles 9 are cramped through extension spring 10 circumference, and rely on the terminal surface of inclined plane on the three lamella formula carbocycles 9 and low pressure sealing ring 13, support tightly three lamella formula carbocycles 9 axial on ventilating sealing ring 7's terminal surface, and set up stop pin 8 and prevent that three lamella formula carbocycles 9 from rotating, make supercritical carbon dioxide medium can only follow three lamella formula carbocycles 9 and main shaft 22's radial little clearance and pass through, can not reveal from the terminal surface, reduce the volume of revealing.
In order to passively reduce the sealing circumferential speed structurally and more accurately control the circumferential flow speed and circumferential pressure uniformity inside the seal, a shell air inlet 14-1 is connected with a self-contained high-pressure storage tank 17 in a supercritical carbon dioxide power generation system through an air inlet pipeline 15, the air inlet pipeline 15 is provided with a flow regulating valve 16, a main shaft 22 is provided with a rotating speed sensor 18, a rotating speed signal is input into a PLC (programmable logic controller) 20 through a signal line 19, and after the rotating speed signal is calculated through a control algorithm built in the PLC, the signal is transmitted to the flow regulating valve 16 through a signal line 21, so that the flow of the rotation blocking gas is controlled, namely the ventilation flow speed of a nozzle hole 7-1 is controlled, and the circumferential air flow speed in the rotation blocking cavity 7-2 and the circumferential pressure distribution in the uniform rotation blocking cavity 7-2 are controlled.
Interpretation of the built-in control algorithm: according to the numerical analysis and experimental research on the consistency of the reverse rotational flows of the rotor sealing system, disclosed by Lujiang et al, for a unit with a determined structure, an optimal flow rate exists in the nozzle hole 7-1 at the same rotating speed, so that the circumferential flow rate of air flow in the sealing cavity is minimum, the circumferential pressure distribution is most uniform, the flow rate of the nozzle hole 7-1 is determined, the flow rate is determined, and each rotating speed corresponds to one vortex-resistant flow rate when the unit is in a variable working condition. Therefore, the corresponding data of the 'rotating speed-flow rate' obtained by simulation calculation is input into the PLC, and for each measured rotating speed, a corresponding flow rate is output.
Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.
Claims (9)
1. The utility model provides a super supercritical carbon dioxide rotary machine hinder revolves damping seal structure, includes casing, main shaft, its characterized in that:
the main shaft is sequentially sleeved with a rotation-resistant sealing ring, a ventilating sealing ring and a low-pressure sealing ring from a high-pressure side to a low-pressure side, the ventilating sealing ring is fixedly arranged on the shell, the ventilating sealing ring is respectively and fixedly connected with the rotation-resistant sealing ring and the low-pressure sealing ring, and labyrinth sealing teeth are respectively arranged on the inner circular surfaces of the rotation-resistant sealing ring and the low-pressure sealing ring;
the inner circular surface of the ventilation sealing ring is provided with a rotation blocking cavity along the circumferential direction, the ventilation sealing ring is provided with a plurality of nozzle holes, the plurality of nozzle holes are uniformly distributed along the circumferential direction of the ventilation sealing ring, each nozzle hole extends along the tangential direction of the main shaft, the shell is provided with a shell air inlet hole, the shell air inlet hole is communicated with all the nozzle holes through an annular groove formed in the shell and is used for spraying rotation blocking air into the rotation blocking cavity through the shell air inlet hole and the nozzle holes, the flow direction of the rotation blocking air is opposite to the rotation direction of the main shaft and is used for reducing the circumferential air flow velocity in the rotation blocking cavity and enabling the circumferential pressure in the rotation blocking cavity to be uniformly distributed.
2. The rotary vibration damping seal structure of a supercritical carbon dioxide rotary machine according to claim 1, characterized in that: the supercritical carbon dioxide rotary machine includes a supercritical carbon dioxide compressor and a supercritical carbon dioxide turbine.
3. The rotary vibration damping seal structure of a supercritical carbon dioxide rotary machine according to claim 1, characterized in that: labyrinth seal teeth are respectively arranged at two ends of the inner circular surface of the ventilating seal ring, and the rotation-resisting cavity is formed between the labyrinth seal teeth.
4. The rotary vibration damping seal structure of a supercritical carbon dioxide rotary machine according to claim 1, characterized in that: the rotation-resisting sealing ring and the low-pressure sealing ring are installed on the ventilating sealing ring in a matched mode through a hole shaft and are fixed through screws.
5. The rotary vibration damping seal structure of a supercritical carbon dioxide rotary machine according to claim 1, characterized in that: the high-pressure side of the rotation-resisting sealing ring is provided with a plurality of rotation-resisting grids which are uniformly distributed along the circumferential direction of the rotation-resisting sealing ring, and when a supercritical carbon dioxide medium enters the rotation-resisting sealing ring from the high-pressure side, the rotation-resisting grids are used for breaking the rotational flow of the supercritical carbon dioxide medium in the circumferential direction, so that the inlet pre-rotation speed when the supercritical carbon dioxide medium enters the labyrinth sealing teeth of the rotation-resisting sealing ring is reduced.
6. The rotary vibration damping seal structure of a supercritical carbon dioxide rotary machine according to claim 1, characterized in that: the ventilating sealing ring and the rotation-resisting sealing ring and the low-pressure sealing ring are respectively provided with an annular mounting groove, three-petal carbon rings are respectively arranged in the mounting grooves, the three-petal carbon rings are hooped tightly through a tension spring, the three-petal carbon rings are encircled on the main shaft, and the three-petal carbon rings are circumferentially positioned through rotation-resisting pins.
7. The rotary vibration damping seal structure of a supercritical carbon dioxide rotary machine according to claim 6, characterized in that: the peripheral face of three lamella formula carbocycles is the inclined plane, and extension spring and the cooperation of hindering rotary seal ring/low pressure sealing ring make three lamella formula carbocycles axial conflict on hindering rotary seal ring/ventilating seal ring's terminal surface, form the little clearance seal of carbocycle.
8. The rotary vibration damping seal structure of a supercritical carbon dioxide rotary machine according to claim 1, characterized in that: the air inlet of the shell is connected with a high-pressure storage tank of the supercritical carbon dioxide power generation system through an air inlet pipeline, a flow regulating valve is arranged on the air inlet pipeline, a rotating speed sensor is arranged on the main shaft, the rotating speed sensor and the flow regulating valve are in signal connection with a PLC (programmable logic controller), and the PLC is used for controlling air inflow according to the rotating speed of the main shaft.
9. The rotary vibration damping seal structure of a supercritical carbon dioxide rotary machine according to claim 8, characterized in that: and carrying out simulation calculation according to the relation between the rotating speed of the main shaft and the flow velocity of the nozzle hole to obtain the relation between the rotating speed of the main shaft and the air inflow, and setting a control algorithm of the flow regulating valve by the PLC according to the relation between the rotating speed of the main shaft and the air inflow.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210009743.XA CN114151547A (en) | 2022-01-06 | 2022-01-06 | Rotary-resisting vibration-damping sealing structure of supercritical carbon dioxide rotary machine |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210009743.XA CN114151547A (en) | 2022-01-06 | 2022-01-06 | Rotary-resisting vibration-damping sealing structure of supercritical carbon dioxide rotary machine |
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| CN114151547A true CN114151547A (en) | 2022-03-08 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114876856A (en) * | 2022-06-07 | 2022-08-09 | 上海齐耀动力技术有限公司 | Supercritical carbon dioxide compressor sealing system and compressor |
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- 2022-01-06 CN CN202210009743.XA patent/CN114151547A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114876856A (en) * | 2022-06-07 | 2022-08-09 | 上海齐耀动力技术有限公司 | Supercritical carbon dioxide compressor sealing system and compressor |
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