CN113431637B - Pure radial type supersonic speed micro turbine structure with air bearing - Google Patents
Pure radial type supersonic speed micro turbine structure with air bearing Download PDFInfo
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- CN113431637B CN113431637B CN202110335189.XA CN202110335189A CN113431637B CN 113431637 B CN113431637 B CN 113431637B CN 202110335189 A CN202110335189 A CN 202110335189A CN 113431637 B CN113431637 B CN 113431637B
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- air bearing
- stator
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- dynamic pressure
- radial
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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
- F01D9/04—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector
- F01D9/041—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector using blades
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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
- F01D17/00—Regulating or controlling by varying flow
- F01D17/10—Final actuators
- F01D17/12—Final actuators arranged in stator parts
- F01D17/14—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits
- F01D17/16—Final actuators arranged in stator parts varying effective cross-sectional area of nozzles or guide conduits by means of nozzle vanes
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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
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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
- F01D5/141—Shape, i.e. outer, aerodynamic form
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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
- F01D5/147—Construction, i.e. structural features, e.g. of weight-saving hollow blades
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Architecture (AREA)
- Magnetic Bearings And Hydrostatic Bearings (AREA)
Abstract
The invention relates to a pure radial type supersonic speed micro turbine structure with an air bearing, which comprises the following components in part by weight: the air flow enters a turbine stator flow passage (5) from the radial direction, and then the flow direction in the turbine is kept radial; the stator consists of stator blades (2), an upper casing (1) and a lower casing (4) to form a scaling flow channel, and the sectional area of the throat part of the stator is equal to the critical area of the designed flow, so that the airflow is accelerated to supersonic speed; the inlet blade of the rotor impeller (3) is blunt to block part of the flow area so as to adapt to the small design flow of the micro turbine; dynamic pressure grooves are formed in the back face and the edge of the rotor impeller (3) and form a dynamic pressure air bearing flow channel with the lower casing (4), and when the rotating speed of the turbine reaches a design value, gas in the dynamic pressure grooves provides supporting force through viscosity to play a role in thrust and radial bearing. The invention can realize the expansion work of small-flow high-pressure gas, and has the characteristics of compact structure, extremely high rotating speed, small required flow, capability of using cold air to do work, high expansion ratio and strong work-doing capacity.
Description
Technical Field
The invention belongs to the field of rotor power mechanical structure design, and relates to a pure radial type supersonic speed micro turbine structure with an air bearing.
Background
The development of rotor power machinery has reached a high technical level, and large-scale gas turbines and steam turbines provide continuous high-power in various fields such as energy, ships, aerospace and the like. On the other hand, the miniaturization of the turbine is always a difficult problem, and the efficiency of the turbine under the condition of small flow and low temperature is far lower than that of the turbine under the ordinary working condition, so that the turbine is frequently powered by solar energy, storage batteries and even piston type heat engines under the low-power application scenes of distributed energy, single-soldier carrying equipment, space satellite functions and the like.
With the development of technology, the power density requirements for low-power application scenarios are also gradually increasing. However, the development of solar energy and storage batteries requires research progress of basic materials science, and the piston type heat engine is close to the theoretical upper limit of efficiency and is difficult to continue to develop. It has become a viable solution to develop a microturbine suitable for low flow, low power applications.
At present, the method of reducing the power drop while miniaturizing the turbine is to increase the expansion ratio. However, the increase of the expansion ratio beyond a certain limit may cause various problems such as supersonic airflow, ultrahigh rotation speed, complex flow field structure, etc., and these problems are difficult to solve in the conventional turbine design.
Therefore, a new turbine structure is proposed to solve or alleviate the above problems, and to achieve further development of power density of small-energy power, which has important practical value.
The invention provides a pure radial type supersonic speed micro turbine structure with an air bearing, which can realize expansion work of small-flow high-pressure gas, and has the characteristics of compact structure, extremely high rotating speed, small required flow, capability of using cold air to do work, high expansion ratio and strong work-doing capacity.
Disclosure of Invention
Technical problem to be solved
The invention provides a pure radial type supersonic speed micro turbine structure with an air bearing, which solves the problems of supersonic speed airflow, ultrahigh rotating speed and complicated flow field structure of the existing small-flow turbine machinery under the high expansion ratio design.
(II) technical scheme
In order to solve the above technical problem, an embodiment of the present invention provides a pure radial supersonic microturbine structure with an air bearing, including:
the air compressor comprises an upper casing 1 and a lower casing 4, wherein a stator blade 2 and a rotor blade wheel 3 are clamped between the upper casing 1 and the lower casing 4, the rotor blade wheel 3 rotates around a rotating shaft R, every two pieces of the stator blade 2 are matched with the upper casing and the lower casing to form a stator airflow channel 5, and the rotor blade wheel 3 is matched with the lower casing 4 to form a dynamic pressure air bearing channel.
In one embodiment, the stator blade 2 is tightly connected to the upper casing 1 and the lower casing 4 without a tip clearance.
In one embodiment, the stator blades 2 are plural in number and are arranged equidistantly in the circumferential direction of the casing.
In one embodiment, every two blades between the stator blades 2 are in a group, and a stator airflow channel 5 generated by matching one group of stator blades with the upper casing 1 and the lower casing 4 has a change rule that the cross-sectional area of the channel is firstly contracted and then expanded.
In one embodiment, the narrowest cross-sectional area A of the stator flow channel 5 cr Comprises the following steps:
where G is the design point mass flow, ρ cr Critical density of gas at design point, c cr And n is the number of the stator blades for the design point gas critical sound velocity.
In one embodiment, the shape of the blades at the inlet of the rotor wheel 3 is blunt and the blade area occupies more than 50% of the inlet area.
In one embodiment, the blades of the rotor wheel 3 are flush in the blade height direction and do not change with radial position changes.
In one embodiment, the disk of the rotor wheel 3 is engraved with dynamic pressure grooves, including radial dynamic pressure grooves 71 and thrust dynamic pressure grooves 72, at the rim and back of the disk.
In one embodiment, the rotor wheel 3 is supported by the hydrodynamic air bearing flow passages without any direct or indirect mechanical connection or contact between the upper casing 1, the lower casing 4 and the stator blades 2.
In one embodiment, the hydrodynamic bearing flow passages include radial bearing flow passages 61 and thrust bearing flow passages 62.
(III) advantageous effects
The invention provides a pure radial type supersonic speed micro turbine structure with an air bearing, which has the following advantages: 1. the blades are used for forming the convergent-divergent flow channel, so that the supersonic speed airflow can be provided, and meanwhile, the partial air inlet problem caused by the use of the convergent-divergent straight nozzle in the traditional method is avoided; 2. the dynamic pressure groove is etched on the rotor impeller wheel disc and is matched with the casing to form a dynamic pressure air bearing structure, so that the problem of a mechanical bearing without adaptation at ultrahigh rotating speed is solved; 3. compared with the variable-vane-height radial rotating axial design of the conventional centripetal turbine, the variable-vane-height radial design has the advantages that the internal flow field is changed from three dimensions to quasi two dimensions, and the design and analysis difficulty is greatly reduced.
Drawings
FIG. 1 is a schematic cross-sectional view of a pure radial supersonic micro-turbine structure with an air bearing of the present invention;
FIG. 2 is a schematic top view of a pure radial supersonic micro-turbine structure with an air bearing (without an upper casing) according to the present invention;
FIG. 3 is a schematic view of a rotor disk radial dynamic pressure groove of a pure radial supersonic speed micro-turbine structure with an air bearing of the present invention;
FIG. 4 is a schematic view of a thrust dynamic pressure groove of a rotor disk of a pure radial supersonic speed micro turbine structure with an air bearing of the invention.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention.
As shown in fig. 1, the structure includes:
the air compressor comprises an upper casing 1 and a lower casing 4, wherein a stator blade 2 and a rotor blade wheel 3 are clamped between the upper casing 1 and the lower casing 4, the rotor blade wheel 3 rotates around a rotating shaft R, every two pieces of the stator blade 2 are matched with the upper casing and the lower casing to form a stator airflow channel 5, and the rotor blade wheel 3 is matched with the lower casing 4 to form a dynamic pressure air bearing channel.
The dynamic pressure gas bearing flow passage comprises a radial dynamic pressure gas bearing flow passage 61 and a thrust dynamic pressure gas bearing flow passage 62. The rim and the back of the rotor wheel 3 are engraved with dynamic pressure grooves including a radial dynamic pressure groove 71 and a thrust dynamic pressure groove 72.
When the turbine works, working medium gas uniformly flows into the stator airflow channel 5 from the circumferential direction, then flows into the rotor impeller 3, and finally is discharged from the gas outlet of the upper casing 1. In the whole working process, gas flows along the radial direction, the gas is discharged axially after the working is finished, and the height of the blade is not changed, so that the flow field is quasi-two-dimensional.
Further, the purely radial design may allow for a tight connection between the stator blades 5 and the upper and lower casings 1, 4 without tip clearance leakage flow.
Furthermore, the blades are used as the supersonic speed stator flow channel to replace a common Laval nozzle, so that full circumferential air inlet can be realized, and the unsteady effect caused by partial air inlet of the nozzle is avoided.
The complexity of flow field design is greatly reduced, and a foundation is laid for using supersonic airflow next time.
As shown in fig. 2, every two blades between every two stator blades 2 are in a group, and a stator airflow channel 5 is generated by the cooperation of one group of stator blades with the upper casing 1 and the lower casing 4, and the sectional area of the channel is changed by first contracting and then expanding.
In one embodiment, the narrowest cross-sectional area A of the stator flow channel 5 cr Comprises the following steps:
where G is the design point mass flow, ρ, for this example cr Critical density of gas at design point, c cr And n is the number of the stator blades for the design point gas critical sound velocity.
In one embodiment, the smallest cross-sectional area of the stator flowpath is located proximate the outlet. However, the position of the minimum cross-sectional area may be adjusted according to specific situations, and different exit airflow mach numbers may be obtained by adjusting the position, which is not limited in the embodiment of the present invention.
By the design, supersonic air flow can be obtained on the premise of not adopting partial air inlet.
As shown in fig. 3, the disk of the rotor wheel 3 is engraved with radial dynamic pressure grooves 71 at the disk edge.
As shown in fig. 4, the disk of the rotor wheel 3 is engraved with thrust dynamic pressure grooves 72 on the back surface of the disk.
In one embodiment, the radial dynamic pressure grooves take a herringbone groove shape, and the thrust dynamic pressure grooves take a spiral groove shape. However, the shape, number, and size of the dynamic pressure grooves may be adjusted according to specific situations, and different bearing capacities and stabilities may be obtained by different adjustments, which is not limited in the embodiments of the present invention.
The rotating speed of the turbine adopting the dynamic pressure air bearing can reach more than one million revolutions per minute, which far exceeds the upper limit of the allowable rotating speed of the existing mechanical bearing, and the micro-engine is easier to realize than the mechanical bearing. The dynamic pressure air bearing is directly etched on the turbine, so that the upper limit of the rotating speed of the turbine can be improved on the premise of compactness.
In conclusion, the invention adopts the stator blades with the convergent-divergent flow channels to realize supersonic airflow under the condition of full circumferential air inlet, adopts the self-provided air bearing to realize ultrahigh rotating speed under the compact condition, adopts the pure radial design to relieve the problem of complicated flow field structure, and realizes the miniaturization of the turbine by solving the three problems.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that are within the spirit and principle of the present invention are intended to be included therein.
Claims (5)
1. A pure radial supersonic speed microturbine structure with an air bearing is characterized in that the structure comprises:
the rotor type engine comprises an upper casing (1) and a lower casing (4), wherein a stator blade (2) and a rotor impeller (3) are clamped between the upper casing (1) and the lower casing (4), and the rotor impeller (3) rotates around a rotating shaft (R);
the stator blades (2) are tightly connected with the upper casing (1) and the lower casing (4), no blade tip clearance exists, every two stator blades (2) are matched with the upper casing and the lower casing to form a stator airflow channel (5), and the sectional area of the channel is in a change rule of contracting and expanding firstly;
the rotor impeller (3) and the lower casing (4) are matched to form a dynamic pressure air bearing flow channel, the dynamic pressure air bearing flow channel comprises a radial air bearing flow channel (61) and a thrust air bearing flow channel (62), no direct or indirect mechanical connection or contact exists among the rotor impeller (3), the upper casing (1), the lower casing (4) and the stator blade (2), the rotor impeller is supported by the dynamic pressure air bearing flow channel, and the blade of the rotor impeller (3) is flush in the blade height direction and does not change along with the change of the radial position.
2. The pure radial supersonic microturbine structure with self-contained air bearing according to claim 1, characterized in that said stator blades (2) are plural in number and arranged equidistantly along the casing circumference.
3. The pure radial supersonic microturbine structure with self-contained aerostatic bearing according to claim 1, characterized in that the narrowest cross-sectional area A of the stator airflow channel (5) cr Comprises the following steps:
where G is the design point mass flow, ρ cr Critical density of gas at design point, c cr And n is the number of the stator blades for the design point gas critical sound velocity.
4. The pure radial supersonic microturbine structure with self-contained air bearing as claimed in claim 1, wherein the shape of the blade at the inlet of the rotor wheel (3) is blunt and the blade area occupies more than 50% of the inlet area.
5. The pure radial supersonic microturbine structure with self-bearing air bearing according to claim 1, wherein the wheel disk of said rotor wheel (3) is engraved with dynamic pressure grooves at the edge and back of the wheel disk, including radial dynamic pressure groove (71) and thrust dynamic pressure groove (72).
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110335189.XA CN113431637B (en) | 2021-03-29 | 2021-03-29 | Pure radial type supersonic speed micro turbine structure with air bearing |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110335189.XA CN113431637B (en) | 2021-03-29 | 2021-03-29 | Pure radial type supersonic speed micro turbine structure with air bearing |
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| CN113431637A CN113431637A (en) | 2021-09-24 |
| CN113431637B true CN113431637B (en) | 2022-08-02 |
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| CN114592925B (en) * | 2022-03-31 | 2023-01-31 | 北京大臻科技有限公司 | Magnetic suspension hydrogen turbine expansion device and method |
| CN114857044B (en) * | 2022-05-13 | 2023-09-12 | 清华大学 | Multi-stage convection shaft air compressor with full air-floating support |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20060034475A (en) * | 2004-10-19 | 2006-04-24 | 한국과학기술연구원 | Micro power generating device |
| CN102046954A (en) * | 2008-03-25 | 2011-05-04 | 友好发明有限责任公司 | Subsonic and stationary ramjet engines |
| CN105387066A (en) * | 2015-11-30 | 2016-03-09 | 北京航空航天大学 | Air bearing system for supporting micro-rotors with high rotation speed and small length-diameter ratio |
| CN110043323A (en) * | 2019-05-16 | 2019-07-23 | 广东索特能源科技有限公司 | A kind of supersonic speed radial-inward-flow turbine |
| CN110714985A (en) * | 2019-10-29 | 2020-01-21 | 北京航空航天大学 | Microminiature air bearing system with middle air supply |
-
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- 2021-03-29 CN CN202110335189.XA patent/CN113431637B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20060034475A (en) * | 2004-10-19 | 2006-04-24 | 한국과학기술연구원 | Micro power generating device |
| CN102046954A (en) * | 2008-03-25 | 2011-05-04 | 友好发明有限责任公司 | Subsonic and stationary ramjet engines |
| CN105387066A (en) * | 2015-11-30 | 2016-03-09 | 北京航空航天大学 | Air bearing system for supporting micro-rotors with high rotation speed and small length-diameter ratio |
| CN110043323A (en) * | 2019-05-16 | 2019-07-23 | 广东索特能源科技有限公司 | A kind of supersonic speed radial-inward-flow turbine |
| CN110714985A (en) * | 2019-10-29 | 2020-01-21 | 北京航空航天大学 | Microminiature air bearing system with middle air supply |
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| CN113431637A (en) | 2021-09-24 |
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