CN107701314B - Flow control method for improving starting performance of air inlet channel by using flexible wall surface - Google Patents
Flow control method for improving starting performance of air inlet channel by using flexible wall surface Download PDFInfo
- Publication number
- CN107701314B CN107701314B CN201711188999.7A CN201711188999A CN107701314B CN 107701314 B CN107701314 B CN 107701314B CN 201711188999 A CN201711188999 A CN 201711188999A CN 107701314 B CN107701314 B CN 107701314B
- Authority
- CN
- China
- Prior art keywords
- air inlet
- flexible wall
- wall surface
- inlet channel
- pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
- F02C7/04—Air intakes for gas-turbine plants or jet-propulsion plants
- F02C7/057—Control or regulation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K7/00—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof
- F02K7/10—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof characterised by having ram-action compression, i.e. aero-thermo-dynamic-ducts or ram-jet engines
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
- Air-Flow Control Members (AREA)
Abstract
A flow control method for improving starting performance of an air inlet channel by utilizing a flexible wall surface relates to an air inlet channel of a ramjet engine. Determining the type selection of the flexible material according to the flow field pressure oscillation frequency and the amplitude when the air inlet channel is not started; determining the size of the flexible wall surface according to the size of an airflow separation area at an inlet of a compression section when the air inlet channel is not started; and determining the initial installation position of the flexible wall surface according to the initial position of the airflow separation area. When the air inlet channel is not started, the pressure of the flow field periodically oscillates to drive the flexible wall surface to generate tiny oscillation, so that the energy of the oscillating flow field is transferred and dissipated to the flexible wall surface, the oscillation of the flow field is restrained, and the purpose of improving the starting characteristic of the hypersonic air inlet channel is achieved. The flexible wall surface follows the flow field oscillation to realize the inhibition of the flow field oscillation and improve the starting characteristic of the hypersonic inlet channel; simple structure, obvious control effect and great engineering application potential.
Description
Technical Field
The invention relates to an air inlet channel of a ramjet engine, in particular to a flow control method for improving starting performance of the air inlet channel by utilizing a flexible wall surface.
Background
The hypersonic air inlet channel is used as a pneumatic component of the ramjet engine which firstly takes the impact, and the performance of the hypersonic air inlet channel directly influences the working characteristics of the whole propulsion system. The air inlet channel is in a stable starting state, which is a premise that the hypersonic propulsion system can work normally, and the phenomenon that a combustion chamber is flamed out and the like is caused when the air inlet channel is in an un-starting state, so that the hypersonic flight state of the aircraft is difficult to maintain. Therefore, the starting performance is one of the key parameters of the hypersonic air inlet passage, and is of great significance to the design of the stamping engine.
The factors causing the non-starting of the air inlet channel are many, such as the flying Mach number is lower than the self-starting Mach number of the air inlet channel, the flying attack angle is too large, the back pressure of the combustion chamber is too high, and the like. Many works have been carried out by scholars at home and abroad for improving the starting characteristic of the air inlet, and the improvement measures can be divided into two aspects: on one hand, the air inlet is optimally designed, and the concept of adjustable air inlet is introduced to improve the shock wave distribution in the air inlet; another aspect is to introduce flow control techniques into the air intake. The current research shows that the starting requirement of a wide-speed-range hypersonic inlet channel is difficult to meet by only depending on the design of the inlet channel, and a flow control technology is necessary to be adopted in the inlet channel. Typical active control in the air inlet channel comprises boundary layer active suction/blowing, magnetic fluid control and the like, and passive flow control comprises a slot/seam, a concave cavity, a vortex generator, a forced transition device and the like. The active flow control can adjust a control scheme according to specific flow field conditions in the working process of the air inlet, so that the starting characteristic and the performance of a design point of the air inlet are obviously improved, the control effect is obvious, and the problems of complex structure, heavy weight and the like are generally caused. The passive control is characterized by simple structure and strong engineering adaptability, but can generate some adverse side effects under some conditions.
At present, the flow control in the air inlet channel aims at the separation near the lip of the air inlet channel or the interference of a shock wave/boundary layer under the non-starting state to carry out flow field control more aiming at the steady-state flow characteristic, and the control principle is based on a steady control thought. However, the current research of the hypersonic air inlet shows that obvious unsteady flow field oscillation phenomenon can be generated in the air inlet in the process of non-starting, and the dynamic evolution characteristics of packet separation oscillation-small surge-large surge (Wang satellite, Guo Wei. the unsteady flow characteristics of the hypersonic air inlet when the self-starting Mach number is lower than the self-starting Mach number. the aeronautical reports, 2012,27(12): 2733-.
Disclosure of Invention
The invention aims to overcome the defects of the existing air inlet flow control technology and provide a flow control method for improving the starting performance of an air inlet by utilizing a flexible wall surface.
The invention comprises the following steps:
1) determining the type selection of the flexible material according to the flow field pressure oscillation frequency and the amplitude when the air inlet channel is not started;
2) determining the size of the flexible wall surface according to the size of an airflow separation area at an inlet of a compression section when the air inlet channel is not started;
3) and determining the initial installation position of the flexible wall surface according to the initial position of the airflow separation area.
The flexible wall surface is made of flexible materials and hinges, is arranged between a compression section and a lip cover of the air inlet channel of the ramjet engine, is connected with front and rear components through the hinges, and can perform tiny oscillation along with pressure oscillation of the flow field of the air inlet channel.
When the air inlet channel is not started, the pressure of the flow field periodically oscillates to drive the flexible wall surface to generate tiny oscillation, so that the energy of the oscillating flow field is transferred and dissipated to the flexible wall surface, the oscillation of the flow field is restrained, and the purpose of improving the starting characteristic of the hypersonic air inlet channel is achieved.
The working principle of the invention is as follows: a flexible wall surface is arranged near an inlet of a compression section of the air inlet channel, and the flexible wall surface is driven to generate tiny oscillation by utilizing the periodic oscillation of the flow field pressure of the air inlet channel in the non-starting state, so that the energy of an oscillation flow field is transferred and dissipated to the flexible wall surface, and the effect of a flow field oscillation damper is generated, thereby realizing the suppression of the flow field oscillation and achieving the purpose of improving the starting characteristic of the hypersonic air inlet channel.
By combining the unsteady flow characteristic of the hypersonic inlet, and reasonably constructing an unsteady control means, the effect more remarkable than that of steady control can be obtained, but the unsteady control technology is more active control, needs an external control device and has poorer engineering practicability. Therefore, the flow control method for improving the starting performance of the hypersonic-speed air inlet passage by utilizing the flexible wall surface has the advantages of remarkable comprehensive unsteady control effect, simple passive control structure and great engineering application potential.
The invention has the beneficial effects that: (1) the flexible wall surface follows the flow field oscillation to realize the inhibition of the flow field oscillation and improve the starting characteristic of the hypersonic inlet channel; (2) the invention has simple structure, obvious control effect and great engineering application potential.
Drawings
FIG. 1 is a schematic view of a flexible wall mounting location;
FIG. 2 is a schematic view of the dimensions of a flexible wall;
FIG. 3 is a schematic diagram of upward deformation of a flexible wall surface following flow field oscillation;
FIG. 4 is a schematic view of the flexible wall surface deforming downward following the flow field oscillation;
FIG. 5 is a flow chart of the flexible wall design of the present invention;
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
As shown in FIG. 1, the flexible wall 3 of the present invention is installed between the inlet compression section 1 and the lip cover 2, and the inlet is composed of the inlet compression section 1 and the lip cover 2.
Firstly, acquiring flow field pressure oscillation frequency f and amplitude p in the non-starting process of an air inlet channel through numerical simulation, establishing a relation between the motion characteristic of the flexible wall and the mechanical property of the material by adopting a flexible wall surface simplification method of a pressure driven type elastic model, and selecting the flexible wall surface material which can realize following oscillation with the frequency f under the pressure drive with the oscillation frequency f and the amplitude p.
Then, as shown in fig. 2, when the intake duct obtained based on the numerical simulation is not started, the size of the flexible wall surface 3 is determined by the size of the airflow separation area 4 at the inlet of the intake duct compression section 1, so that the length of the flexible wall surface 3 is consistent with the length of the separation area on the intake duct compression section 1. Wherein, the flexible wall surface is connected with the front and the rear parts by a hinge 5 when being installed. In fig. 2, reference numeral 6 is the initial position of the flexible wall mounting.
Finally, when the inlet is not started, the inlet of the inlet generates obvious phenomenon of periodically enlarging and reducing the airflow separation area, and the periodically enlarging and reducing energy of the separation area is derived from the periodic change of the airflow pressure. As shown in fig. 3, when the separation region is reduced, the instantaneous pressure is low, the pressure of the flexible wall surface 3 near the flow field is lower than the pressure of the cavity, the flexible wall surface 3 deforms upward 7, and the gas pressure in the cavity can be converted into the kinetic energy and the elastic potential energy of the upward movement of the flexible wall surface 3. As shown in fig. 4, when the separation area becomes larger, the instantaneous pressure is high, the pressure of the flexible wall surface 3 near the flow field is higher than the pressure in the cavity, the flexible wall surface 3 deforms downward 8, the instantaneous high-pressure energy of the gas is converted into the kinetic energy and the elastic potential energy of the flexible wall surface 3 moving downward, and the instantaneous oscillation energy of the gas is reduced. Due to the existence of the flexible wall surface 3, the flow field oscillation energy is transferred to the flexible wall surface 3 and gradually dissipated, the periodic oscillation characteristic of the flow field of the air inlet in the non-starting process is weakened, the periodic enlarging and reducing phenomena of the inlet separation area of the air inlet are inhibited, the maximum size of the separation area is reduced, the corresponding circulation capacity is enhanced, and the starting performance of the air inlet is improved.
Referring to fig. 5, the flexible wall surface design process of the present invention includes:
1) determining the type selection of the flexible material according to the flow field pressure oscillation frequency and the amplitude when the air inlet channel is not started;
2) determining the size of the flexible wall surface according to the size of an airflow separation area at an inlet of a compression section when the air inlet channel is not started;
3) and determining the initial installation position of the flexible wall surface according to the initial position of the airflow separation area.
When the air inlet channel is not started, the pressure of the flow field periodically oscillates to drive the flexible wall surface to generate tiny oscillation, so that the energy of the oscillating flow field is transferred and dissipated to the flexible wall surface, the oscillation of the flow field is restrained, and the purpose of improving the starting characteristic of the hypersonic air inlet channel is achieved.
Claims (1)
1. A flow control method for improving starting performance of an air inlet channel by utilizing a flexible wall surface is characterized by comprising the following steps:
1) the method comprises the following steps of determining the type selection of the flexible material according to the flow field pressure oscillation frequency and the amplitude when the air inlet channel is not started, and specifically comprises the following steps: acquiring flow field pressure oscillation frequency and amplitude in the non-starting process of the air inlet channel through numerical simulation, establishing a relation between the motion characteristic of the flexible wall and the mechanical property of the material by adopting a flexible wall simplifying method of a pressure-driven elastic model, and selecting a flexible wall material which can realize following oscillation with frequency under the pressure drive of oscillation frequency and amplitude; the flexible wall surface is arranged between the air inlet compression section and the lip cover, and the air inlet is composed of the air inlet compression section and the lip cover;
2) the method comprises the following steps of determining the size of a flexible wall surface according to the size of an airflow separation area at an inlet of a compression section when an air inlet channel is not started, and specifically comprises the following steps: when the air inlet obtained based on numerical simulation is not started, the size of the flexible wall surface is determined by the size of the airflow separation area at the inlet of the compression section of the air inlet, so that the length of the flexible wall surface is consistent with the length of the separation area on the compression section of the air inlet;
3) the method comprises the following steps of determining the mounting initial position of the flexible wall surface according to the initial position of the airflow separation area, and specifically comprises the following steps: when the air inlet channel is not started, the inlet of the air inlet channel generates obvious phenomenon of periodic enlargement and reduction of an airflow separation area, the periodic enlargement and reduction energy of the separation area is derived from periodic change of airflow pressure, the instantaneous pressure is low when the separation area is reduced, the pressure of the side, close to the flow field, of the flexible wall surface is lower than the pressure of the cavity, the flexible wall surface deforms upwards, the pressure energy of air in the cavity is converted into kinetic energy and elastic potential energy of upward movement of the flexible wall surface, the instantaneous pressure is high when the separation area is enlarged, the pressure of the side, close to the flow field, of the flexible wall surface is higher than the pressure of the cavity, the flexible wall surface deforms downwards, the instantaneous high-pressure energy of air is converted into kinetic energy and; due to the existence of the flexible wall surface, the flow field oscillation energy is transferred to the flexible wall surface and gradually dissipated, the periodic oscillation characteristic of the flow field of the air inlet in the non-starting process is weakened, the periodic enlarging and reducing phenomena of the inlet separation area of the air inlet are inhibited, the maximum size of the separation area is reduced, the corresponding circulation capacity is enhanced, and the starting performance of the air inlet is improved.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711188999.7A CN107701314B (en) | 2017-11-24 | 2017-11-24 | Flow control method for improving starting performance of air inlet channel by using flexible wall surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711188999.7A CN107701314B (en) | 2017-11-24 | 2017-11-24 | Flow control method for improving starting performance of air inlet channel by using flexible wall surface |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107701314A CN107701314A (en) | 2018-02-16 |
| CN107701314B true CN107701314B (en) | 2020-04-24 |
Family
ID=61180913
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711188999.7A Active CN107701314B (en) | 2017-11-24 | 2017-11-24 | Flow control method for improving starting performance of air inlet channel by using flexible wall surface |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107701314B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108999704B (en) * | 2018-08-17 | 2019-09-27 | 中国人民解放军国防科技大学 | Hypersonic air inlet starting method and starting device |
| CN112268709B (en) * | 2020-10-15 | 2021-08-03 | 厦门大学 | Design method of aircraft engine dynamic pressure distortion generator based on conical cavity |
| CN113788151A (en) * | 2021-08-26 | 2021-12-14 | 厦门大学 | Hypersonic-speed air inlet channel forced transition method based on macro-pore structure |
| CN114542288B (en) * | 2022-01-10 | 2024-04-30 | 南京航空航天大学 | Self-adaptive drainage hypersonic air inlet channel |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103790710B (en) * | 2014-01-22 | 2015-12-02 | 西北工业大学 | A kind of rocket based combined cycle motor structure changes intake duct |
| CN104384288B (en) * | 2014-11-19 | 2016-11-02 | 中国航空工业集团公司沈阳飞机设计研究所 | A kind of self adaptation bump inlet shape control method based on flexible covering |
| CN104863716B (en) * | 2015-04-24 | 2016-01-13 | 南京航空航天大学 | Based on the design method of oblique shock wave in the intake duct of binary bulge/boundary layer interference control measure |
| CN105221268B (en) * | 2015-09-23 | 2017-12-12 | 西北工业大学 | A kind of air inlet adjustment structure of Ducted rocket |
| CN107091159B (en) * | 2017-06-16 | 2018-07-31 | 南京航空航天大学 | The design method of the adjustable Supersonic Inlet of axial symmetry based on flexible central body |
-
2017
- 2017-11-24 CN CN201711188999.7A patent/CN107701314B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN107701314A (en) | 2018-02-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107701314B (en) | Flow control method for improving starting performance of air inlet channel by using flexible wall surface | |
| Yen et al. | Enhancing vertical axis wind turbine by dynamic stall control using synthetic jets | |
| Yen et al. | Improving safety and performance of small-scale vertical axis wind turbines | |
| CN104481700B (en) | Assembly power axisymmetric becomes geometry intake duct, motor and intake duct controlling method | |
| US8226047B2 (en) | Reduction of tip vortex and wake interaction effects in energy and propulsion systems | |
| CN108087473B (en) | Gas-liquid bullet dual-frequency vibration isolator | |
| CN108001669B (en) | Leading edge slat noise suppression method based on zero-mass jet control | |
| WO2013163406A1 (en) | Method of using an active flow control system for lift enhancement or destruction | |
| US6899302B1 (en) | Method and device for altering the separation characteristics of flow over an aerodynamic surface via hybrid intermittent blowing and suction | |
| Hong | Effectiveness of micro synthetic jet actuator enhanced by flow instability in controlling laminar separation caused by adverse pressure gradient | |
| CN112014061A (en) | Vibration damper of oscillating blade gust generator | |
| CN111516891B (en) | Exciter capable of simultaneously realizing steady air suction and oscillation air blowing | |
| CN201489118U (en) | Cylinder type vibroseis vibrator | |
| CN205824027U (en) | A kind of electromechanical integration pulsator controller | |
| CN203939811U (en) | A kind of cylinder | |
| CN103671249A (en) | Centrifugal-type fan impeller blade with local flexible structure | |
| CN103821800B (en) | Based on the active vortex generator of electromagnetic exciting | |
| Traub et al. | Effects of synthetic jet actuation on a ramping NACA 0015 airfoil | |
| Ja'fari et al. | Synthetic jet actuators: Overview and applications | |
| CN108665884B (en) | Concave cavity noise suppression method based on rotary slotted cylinder | |
| CN207609482U (en) | A kind of device promoting intake duct starting performance using flexible wall surface | |
| CN115387908A (en) | Air inlet passage isolation section flow control device based on wall plate aeroelastic effect and design method | |
| CN114893429B (en) | Compressor clearance leakage flow control method based on shock wave deceleration effect and compressor | |
| Sinha et al. | Review of the flow-field analysis over cavities | |
| Yao et al. | Effect of wall deformation on aerodynamic performance for mixed compression intake |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |