CN108225716A - A kind of test method for measuring oxygen-iodine laser boundary layer flow state - Google Patents
A kind of test method for measuring oxygen-iodine laser boundary layer flow state Download PDFInfo
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- CN108225716A CN108225716A CN201611143192.7A CN201611143192A CN108225716A CN 108225716 A CN108225716 A CN 108225716A CN 201611143192 A CN201611143192 A CN 201611143192A CN 108225716 A CN108225716 A CN 108225716A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
- G01M9/06—Measuring arrangements specially adapted for aerodynamic testing
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- General Physics & Mathematics (AREA)
- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
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Abstract
A kind of test method for measuring oxygen-iodine laser boundary layer flow state, for measuring flow regime of the oxygen-iodine laser supersonic speed cold flow field border layer fluid under different back pressures.The invention designs in iodine hole near jet pipe side wall surface, does not have iodine hole in the central area of jet pipe, using the method for induced with laser iodine fluorescence, by fluorescent state of the iodine molecule at wall surface under different aerodynamic conditions, characterizes the flow regime in boundary layer.This method in the case where not influencing primary air flow performance and stream field not generating interference, can measure the flowing of oxygen-iodine laser cold flow boundary layer fluid off field, the validity of decision boundaries coating control method.
Description
Technical field
The present invention relates to a kind of test methods for measuring oxygen-iodine laser boundary layer flow state, can using the technical solution
With flow regime of the observational measurement oxygen-iodine laser supersonic speed cold flow field border layer fluid under different back pressures, decision boundaries layer control
Method processed is to the validity of boundary layer separation.
Background technology
Oxygen-iodine laser is the Typical Representative of air-flow chemical laser, and the expansion of air-flow is typically each realized using array jet pipe
Cooling and the hybrid reaction of chemical mediator, since nozzle entry size is small, density is low, therefore Reynolds number is small, in jet pipe rear end
Optical cavity on lower wall surface can form very thick boundary layer.Boundary layer has adverse effect the operation of laser, is flowed in laser
A variety of wave system structures and boundary layer interaction existing for can lead to the uneven of gain region gain and index distribution, especially
It is the Asia for being close to wall surface when the pressure of optical cavity rear end (commonly referred to as " back pressure ") is constantly increased with the passage of working time
Velocity of sound boundary layer fluid can gradually be slowed down by the effect of inverse pressure and viscosity, until after speed is zero, flow backwards squeezing for fluid below
Pressure is detached from wall flow internally mainstream, leads to the separation of boundary layer flow.Segregation phenomenon can generate central area flow field strong
Strong additional disturbance reduces the resistance back pressure ability of laser.
In actual laser device, boundary is usually controlled using Boundary layer flow method in optical cavity or diffuser portion
The separation of layer, but due to oxygen-iodine laser low-density, the flow behavior of high speed, current popular particle figure can not be used
As instrument measuring method, and hot line instrument exists due to stream field compared with large disturbances so that less in the application of oxygen-iodine laser.Therefore,
Development measures the test method of oxygen-iodine laser boundary layer flow state, using contactless measuring system, measures different gas
Boundary layer flow state under the conditions of dynamic, can differentiate the validity of boundary layer control method, for oxygen-iodine laser
The control of boundary layer separation is of great significance.
Invention content
In order to oxygen-iodine laser Supersonic Flow boundary layer discrete state and the progress of Boundary layer flow method validity
Characterization, the present invention provide a kind of test method for measuring oxygen-iodine laser boundary layer flow state, being capable of observational measurement air-flow
Flow regime of the laser ultrasonic cold flow field border layer fluid under different back pressures is learned, the application of decision boundaries coating control method
Validity.
The technical solution adopted by the present invention to solve the technical problems is：
A kind of test method for measuring oxygen-iodine laser boundary layer flow state, is on traditional supersonic jet pipe and optical cavity
It is improved, nozzle contour is included subsonic speed section along airflow direction jet pipe, shunk using designing scheme commonly used in engineering
Section and supersonic speed section are equipped with iodine with the left side side wall and/or right sidewall close to jet pipe square duct upper wall surface and lower wall surface
Hole is equipped with a pair of of transparent window in the adjacent wall wall surface of rectangular optical cavity, is connect in laser light source by light arm with sheet laser,
Sheet laser is located at the transparent window of optical cavity up or down cover board, the optical axis side of the light that sheet laser is sent out and oxygen-iodine laser resonator
To vertical, the light that sheet laser is sent out is injected from the transparent window of optical cavity up or down cover board in the flow field of gain region, optical cavity exterior side wall
CCD camera, the area where the light that CCD camera camera lens is sent out towards sheet laser by transparent window are equipped at the transparent window in face
Domain, CCD camera acquire the fluorescence signal of iodine molecule, and the fluorescence signal of acquisition is transmitted to control system preservation.Using induced with laser
Iodine fluorescence principle using the flow regime of the state representation gain region boundary layer fluid of iodine fluorescence at wall surface, observes different back pressures
Under iodine fluorescent image, the boundary layer flow state under present condition can be analyzed.
The invention has the advantages that
1. the present invention based on induced with laser iodine fluorescence principle, passes through iodine fluorescence in jet pipe near wall incidence iodine molecule
State of the state representation boundary layer flow under different back pressures, can be with observational measurement air-flow chemical laser supersonic speed cold flow field side
The flow performance of interlayer differentiates the validity of boundary layer control method.
2. the present invention is set using the existing iodine hole of oxygen-iodine laser, the flow regime of laser flow field will not be changed,
Fluorescent material iodine be oxygen-iodine laser need to medium, no stream field interfered, and improves the reliability of measurement result.
Description of the drawings
The present invention is further described with reference to the accompanying drawings and examples.
Fig. 1 is the structural map of the embodiment of the present invention；
Fig. 2 a are the boundary layer flows under the low back pressure measured using the present invention；
Fig. 2 b are the boundary layer flows under the high back pressure measured using the present invention.
Wherein 1. jet pipes, 2. jet pipe top and bottom sidewalls, 3. iodine holes, 4. optical cavities, 5. optical cavity upper and lower cover platess, 6.Nd:YAG laser
Device, 7. smooth arms, 8. sheet lasers, 9.CCD cameras, 10. computer
Specific embodiment
A kind of test method for measuring oxygen-iodine laser boundary layer flow state, it is shown in Figure 1.1 type face of jet pipe uses
Commonly used designing scheme in engineering, jet pipe use metal material, along airflow direction jet pipe include subsonic speed section, contraction section and
Supersonic speed section separately designs 3 iodine holes 3, first iodine in subsonic speed section by the front-rear side walls face of two close end jet pipe top and bottom sidewall 2
Pitch-row is from wall surface 1mm, iodine bore dia 0.5mm, and iodine pitch of holes is 2mm, and other regions do not have an iodine hole, and jet pipe height is 50mm, light
The upper and lower cover plates 5 of chamber 4 and the adjacent wall surface vertical with upper and lower cover plates use organic glass window.Nd:YAG laser 6 passes through
Light arm 7 is connect with sheet laser 8, and sheet laser is by Nd:The Shu Guang for the 532nm that YAG laser is sent out transforms into the piece that thickness is 0.5-1mm
Light, it is vertical with optical axis direction to illuminate flow region, the CCD camera 9 and piece that acquisition wavelength is 200-900nm from the upper cover plate of optical cavity
The fluorescent image of light vertical reception iodine, computer 10 are used for controlling laser and acquire the sequential of signal, existed by collected iodine
The flow performance in the fluorescent state analysis boundary layer under different aerodynamic conditions.
The iodine fluorescence of oxygen-iodine laser cold flow field is measured as schemed in low back pressure and high back pressure using this test method
Shown in 2a and Fig. 2 b, it can be seen that with the increase of back pressure, iodine fluorescence area significantly increases, and reflects boundary layer fluid by inverse
The phenomenon that influence of pressure gradient, detaches from wall surface, and boundary layer thickness thickens.
Claims (7)
1. a kind of test method for measuring oxygen-iodine laser boundary layer flow state, using induced with laser iodine fluorescence measuring systems,
The flow regime of gain region boundary layer fluid is characterized by the fluorescent state of iodine molecule at wall surface, it is characterised in that：In close to spray
The front side sidewall and/or rear side sidewall of pipe square duct upper wall surface and lower wall surface are equipped with iodine hole, in the sides adjacent of rectangular optical cavity
Wall wall surface is equipped with a pair of of transparent window, is connect in laser light source by light arm with sheet laser, sheet laser is located at optical cavity up or down
At the transparent window of cover board, the light that sheet laser is sent out is vertical with the optical axis direction of oxygen-iodine laser resonator, what sheet laser was sent out
Light is injected from the transparent window of optical cavity up or down cover board in the flow field of gain region, is equipped at the transparent window of optical cavity outer side wall surface
CCD camera, the region where the light that CCD camera camera lens is sent out towards sheet laser by transparent window, CCD camera acquisition iodine molecule
Fluorescence signal, the fluorescence signal of acquisition is transmitted to control system preservation.
2. according to the method described in claim 1, it is characterized in that：The control system is computer, microcontroller or PLC control
Device；Control system is connect with laser and CCD camera signal；Control system is used to controlling the triggering of laser optical source signal and glimmering
The acquisition of light image.
3. according to the method described in claim 1, it is characterized in that：Jet pipe side wall surface is perpendicular to the height of fluid flow direction
More than 40mm；
It is the double or single-row arrangement perpendicular to upper wall surface close to the iodine hole of upper wall surface, iodine bore dia is 0.1-0.8mm, between iodine hole
Away from for 1-2mm, iodine hole number is 1-5；
It is the double or single-row arrangement perpendicular to lower wall surface close to the iodine hole of lower wall surface, iodine bore dia is 0.1-0.8mm, between iodine hole
Away from for 1-2mm, iodine hole number is 1-5.
4. the method according to claim 1 or 3, it is characterised in that：The first iodine hole centre distance from up or down wall surface
Jet pipe up or down wall surface spacing is 0.3-2mm.
5. according to the method described in claim 1, it is characterized in that：Plane where the geometric center line of a pair of of transparent window with
Gas flow direction is vertical in optical cavity, and the light that central axis and the sheet laser of CCD camera camera lens are sent out is perpendicular, and transparent window is
Using organic glass or the transparent window of quartz glass material, transparent window and optical cavity cavity wall surface airtight connection.
6. according to the method described in claim 1, it is characterized in that：The wavelength of laser light source is 400-600nm wave bands.
7. according to the method described in claim 1, it is characterized in that：The acquisition wavelength of CCD will include 420-700nm wave bands.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201611143192.7A CN108225716A (en) | 2016-12-13 | 2016-12-13 | A kind of test method for measuring oxygen-iodine laser boundary layer flow state |
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| CN201611143192.7A CN108225716A (en) | 2016-12-13 | 2016-12-13 | A kind of test method for measuring oxygen-iodine laser boundary layer flow state |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11233860A (en) * | 1998-02-17 | 1999-08-27 | Oyo Kogaku Kenkyusho | Chemical laser equipment |
| CN103884711A (en) * | 2012-12-21 | 2014-06-25 | 中国科学院大连化学物理研究所 | Testing method of oxygen/iodine ultrasonic mixing heat flow field |
-
2016
- 2016-12-13 CN CN201611143192.7A patent/CN108225716A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11233860A (en) * | 1998-02-17 | 1999-08-27 | Oyo Kogaku Kenkyusho | Chemical laser equipment |
| CN103884711A (en) * | 2012-12-21 | 2014-06-25 | 中国科学院大连化学物理研究所 | Testing method of oxygen/iodine ultrasonic mixing heat flow field |
Non-Patent Citations (5)
| Title |
|---|
| CARRIE A. NOREN 等: "PLIF Flow Visualization of a Supersonic Injection COIL Nozzle", 《36TH AIAA PLASMADYNAMICS AND LASERS CONFERENCE》 * |
| CARRIE A. NOREN 等: "Quantitative Mixing Measurements of a Supersonic Injection COIL Nozzle with Trip Jets", 《39TH PLASMADYNAMICS AND LASERS CONFERENCE》 * |
| JAMES M. DONOHUE 等: "Computer-Controlled Multiparameter Flowfield Measurements Using Planar Laser-Induced Iodine Fluorescence", 《AIAA JOURNAL》 * |
| TIMOTHY J. MADDEN 等: "A method for comparison of computational fluid dynamic simulation and planar laser induced fluorescence images for a supersonic flowfield", 《PROCEEDINGS OF SPIE》 * |
| 怀英 等: "化学氧碘激光器内流场亚跨超音速混合的大涡模拟研究", 《强激光与粒子束》 * |
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Application publication date: 20180629 |
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