CN114838900A - Optical compensation method and device for wind tunnel experiment - Google Patents
Optical compensation method and device for wind tunnel experiment Download PDFInfo
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- CN114838900A CN114838900A CN202210503454.5A CN202210503454A CN114838900A CN 114838900 A CN114838900 A CN 114838900A CN 202210503454 A CN202210503454 A CN 202210503454A CN 114838900 A CN114838900 A CN 114838900A
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- wind tunnel
- optical compensator
- spray pipe
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- 230000003287 optical effect Effects 0.000 title claims abstract description 70
- 238000000034 method Methods 0.000 title claims abstract description 16
- 239000007921 spray Substances 0.000 claims abstract description 37
- 239000000463 material Substances 0.000 claims abstract description 8
- 239000005304 optical glass Substances 0.000 claims description 9
- 238000003384 imaging method Methods 0.000 claims description 3
- 230000001678 irradiating effect Effects 0.000 claims description 3
- 238000005516 engineering process Methods 0.000 abstract description 3
- 239000011521 glass Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
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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
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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
- G01M9/02—Wind tunnels
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- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
The invention discloses an optical compensation method and device for wind tunnel experiments, wherein the method comprises the following steps: adding an optical compensator at a spray pipe of a wind tunnel, wherein the optical compensator and the spray pipe of the wind tunnel are made of the same materials; step two, all the light rays pass through the optical compensator and the spray pipe in sequence; and step three, after all the light rays penetrate through the spray pipe, the original irradiation direction is still kept. The device comprises the spray pipe and the optical compensator, light rays vertically enter through the optical compensator and the spray pipe and are vertically emitted, sheet light incidence and scattering signals of flow display technologies such as NPLS and PIV are convenient to acquire, and fine structure flow display experimental research of a flow field of the Laval spray pipe becomes possible.
Description
Technical Field
The invention relates to an optical compensation method and device for a wind tunnel experiment.
Background
The vertical incident light is not vertically emergent after being refracted twice by the upper surface and the lower surface of the optical glass with uneven thickness, so that the concentration of particles in the wind tunnel cannot be reflected by the light intensity in the wind tunnel, and the condition in the wind tunnel cannot be observed conveniently, so that the requirement of flow display experimental research cannot be met.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides an optical compensation method and device for a wind tunnel experiment.
In order to achieve the purpose, the invention is realized by the following technical scheme:
an optical compensation method for wind tunnel experiments comprises the following steps:
adding an optical compensator at a spray pipe of a wind tunnel, wherein the optical compensator and the spray pipe of the wind tunnel are made of the same materials;
step two, all the light rays pass through the optical compensator and the spray pipe in sequence;
and thirdly, irradiating all light rays to the flow field through the optical glass on the left side and the right side, and then scattering the light rays to a CCD camera for imaging, thereby realizing the flow display experimental study on the fine structure of the flow field in the Laval nozzle.
Preferably, the optical compensator is used to correct the light ray deflection.
Preferably, the refractive indices of the optical compensator and the nozzle of the wind tunnel are the same.
Preferably, the tangent of the optical compensator at the incident point of all the rays is completely parallel to the tangent of the nozzle at the exit point of the corresponding ray.
Preferably, all the light rays can be connected into a smooth plane at the incident point of the optical compensator.
The device for the optical compensation method for the wind tunnel experiment comprises a spray pipe and optical glass on the left side and the right side of an optical compensator, wherein the optical compensator is installed at the top end of the spray pipe, and the optical glass on the left side and the right side is installed below the optical compensator.
The invention has the following beneficial effects: the invention corrects the light deflection by adding the optical compensator, so that the light is vertically incident and vertically emergent through the optical compensator and the spray pipe, the sheet light incidence and scattering signal collection of flow display technologies such as NPLS, PIV and the like are facilitated, and the fine structure flow display experimental study of the flow field of the Laval spray pipe becomes possible.
Drawings
FIG. 1 is a schematic view of light rays refracted through a glass block;
FIG. 2 is a schematic view of an optical compensator and a nozzle;
FIG. 3 is a schematic view of an optical compensator and light rays within a nozzle;
FIG. 4 is a schematic diagram of finding the incident point of an optical compensator;
FIG. 5 is a schematic view of a lower surface curve of the nozzle;
FIG. 6 is a schematic view of an incident ray;
1. incident light 2, glass brick 3, normal 4, emergent light 5, optical compensator 6 and spray pipe.
Detailed Description
The technical scheme of the invention is further explained by combining the attached drawings of the specification:
an optical compensation method for wind tunnel experiments comprises the following steps:
adding an optical compensator at a wind tunnel spray pipe, wherein the optical compensator and the wind tunnel spray pipe are made of completely same materials, so that the refractive indexes of the optical compensator and the wind tunnel spray pipe are the same, and the optical compensator is used for correcting light deflection;
and secondly, all the rays successively pass through the optical compensator and the spray pipes, the tangent lines of the optical compensator at the incident points of all the rays are completely parallel to the tangent line of the spray pipe at the corresponding ray exit point, and all the rays can be connected into a smooth plane at the incident points of the optical compensator, so that the shape of the upper surface of the optical compensator can be determined by connecting all the incident points. Therefore, the aim is achieved, and light rays are vertically incident and vertically emergent through the optical compensator and the spray pipe;
and thirdly, irradiating all light rays to the flow field through the optical glass on the left side and the right side, and then scattering the light rays to a CCD camera for imaging, thereby realizing the flow display experimental study on the fine structure of the flow field in the Laval nozzle. All light rays still keep the original irradiation direction after penetrating through the spray pipe, so that the experimental study on the flow display of the flow field fine structure in the Laval spray pipe is realized.
The device for the optical compensation method for the wind tunnel experiment comprises a wind tunnel spray pipe and an optical compensator, wherein the optical compensator is installed on the outer side of the wind tunnel spray pipe, and optical glass is installed below the optical compensator.
Knowing that light rays are vertically emitted from the beginning after vertically incident light rays pass through the optical compensator and the spray pipe, the optical compensator and the spray pipe are made of the same materials, and knowing that the light rays can reach the state that the emergent light rays 4 are parallel to the incident light rays 1 only after passing through a refraction route as shown in figure 1, the optical compensator 5 and the spray pipe 6 can be considered as a whole, namely the incident point and the material shape at the emergent point of the light rays in the whole are completely parallel as shown in figure 2.
Since the nozzle material is constant, the refractive index is constant, so we can know the path of the light in the whole body according to the shape and slope of the lower edge of the nozzle as shown in fig. 3.
The entrance point of the optical compensator should be exactly the same shape as the exit point, as shown in fig. 4.
Namely, the incident point should satisfy three conditions:
on the imaginary line (i.e. light on the inner path of the optical compensator and the nozzle)
② the tangent of the optical compensator 5 at the incident point is completely parallel to the spray pipe 6 at the corresponding light ray exit point
And thirdly, incident points can be connected into a smooth plane to meet the conditions.
Thus we can determine the shape of the upper surface of the optical compensator 5 by connecting all the points of incidence. Therefore, the aim is achieved, and light rays are vertically incident and vertically emergent through the optical compensator and the spray pipe.
The specific operation process is as follows:
firstly, fitting a curve in a two-dimensional coordinate system according to the lower surface of the spray pipe
And y ═ f (x), as shown in fig. 5.
(x) known as k ═ f' (x) 1 )＝-tanθ 2 I.e. theta 2 ＝-arctan[f′(x 1 )]
According to the law of refraction
n 1 sinθ 1 ＝n 2 sinθ 2
Knowing n 1 ，n 2 ，θ 2 Then can ask for
Thirdly, as can be seen from FIG. 6, the angle between the incident light and the vertical direction is θ 1 -θ 2
Then k 2 ＝-cot(θ 1 -θ 2 )
The equation for the incident ray is therefore y-cot (θ) 1 -θ 2 )(x-x 1 )+f(x 1 )
Taking a point 2 close to point 1 on the curve y ═ f (x), and recording the coordinate as
Repeating the above steps to obtain the incident light
Setting the upper surface line of optical compensator as y ═ g (x), setting the exit point x 1 Corresponding incident point is x 1 '. According to the three conditions which are deduced from the above and should be satisfied by the incident point, the intersection point of the surface line of the optical compensator and the incident ray is the incident point, and the tangent line of the optical compensator at the incident point is completely parallel to the spray pipe at the corresponding ray exit point, namely, the simultaneous equations are:
y 1 '＝g(x 1 ′)
g'(x 1 ′)＝f′(x 1 )
all the incident points are connected and a curve y ═ g (x) is fitted.
The invention corrects the light deflection by adding the optical compensator, so that the light is vertically incident and vertically emergent through the optical compensator and the spray pipe, the sheet light incidence and scattering signal collection of flow display technologies such as NPLS, PIV and the like are facilitated, and the fine structure flow display experimental study of the flow field of the Laval spray pipe becomes possible.
It should be noted that the above list is only one specific embodiment of the present invention. It is clear that the invention is not limited to the embodiments described above, but that many variations are possible, all of which can be derived or suggested directly from the disclosure of the invention by a person skilled in the art, and are considered to be within the scope of the invention.
Claims (6)
1. An optical compensation method for wind tunnel experiments is characterized by comprising the following steps:
adding an optical compensator at a spray pipe of a wind tunnel, wherein the optical compensator and the spray pipe of the wind tunnel are made of the same materials;
step two, all the light rays pass through the optical compensator and the spray pipe in sequence;
and thirdly, irradiating all light rays to the flow field through the optical glass on the left side and the right side, and then scattering the light rays to a CCD camera for imaging, thereby realizing the flow display experimental study on the fine structure of the flow field in the Laval nozzle.
2. The optical compensation method for the wind tunnel experiment according to claim 1, wherein the optical compensator is used for correcting the light ray deflection.
3. The optical compensation method for the wind tunnel experiment according to claim 1, wherein the optical compensator and the nozzle of the wind tunnel are made of the same material and have the same refractive index.
4. The optical compensation method for the wind tunnel experiment according to claim 1, wherein the tangent of the optical compensator at the incident point of all the rays is parallel to the tangent of the nozzle at the corresponding exit point of the rays.
5. The optical compensation method for wind tunnel experiment according to claim 1, wherein all the light rays can be connected into a smooth plane at the incident point of the optical compensator.
6. The device of claim 1, wherein the device comprises a nozzle, an optical compensator, and left and right optical glasses, wherein the optical compensator is mounted at the top end of the nozzle, and the left and right optical glasses are mounted below the optical compensator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210503454.5A CN114838900A (en) | 2022-05-09 | 2022-05-09 | Optical compensation method and device for wind tunnel experiment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210503454.5A CN114838900A (en) | 2022-05-09 | 2022-05-09 | Optical compensation method and device for wind tunnel experiment |
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| Publication Number | Publication Date |
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| CN114838900A true CN114838900A (en) | 2022-08-02 |
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| CN202210503454.5A Pending CN114838900A (en) | 2022-05-09 | 2022-05-09 | Optical compensation method and device for wind tunnel experiment |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090038407A1 (en) * | 2005-03-14 | 2009-02-12 | Federalnoe Gosudarstvennoe Unitarnoe Predprijatie Central Aerohydrodynamic Institute | Method of gas or liquid flow visualization on an object surface |
| CN106979853A (en) * | 2017-04-01 | 2017-07-25 | 西安交通大学 | It is a kind of to be used for FLOW VISUALIZATION, the experimental provision of measurement and method |
| CN108613791A (en) * | 2018-05-29 | 2018-10-02 | 南京航空航天大学 | A kind of incident shock three-dimensional structure measurement apparatus and measurement method |
| CN110823498A (en) * | 2019-07-16 | 2020-02-21 | 中国人民解放军空军工程大学 | High-speed schlieren-based supersonic velocity separation area measuring device and measuring method |
| CN210937655U (en) * | 2019-11-22 | 2020-07-07 | 江苏锐通激光科技有限公司 | Adjusting device for light path/light deflection |
| US20200218064A1 (en) * | 2017-07-11 | 2020-07-09 | Technische Universität Dresden | Arrangement and method for disturbance correction for imaging flow measuring processes |
| CN113092056A (en) * | 2021-04-25 | 2021-07-09 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Method for measuring three-dimensional density field of hypersonic flow field |
-
2022
- 2022-05-09 CN CN202210503454.5A patent/CN114838900A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090038407A1 (en) * | 2005-03-14 | 2009-02-12 | Federalnoe Gosudarstvennoe Unitarnoe Predprijatie Central Aerohydrodynamic Institute | Method of gas or liquid flow visualization on an object surface |
| CN106979853A (en) * | 2017-04-01 | 2017-07-25 | 西安交通大学 | It is a kind of to be used for FLOW VISUALIZATION, the experimental provision of measurement and method |
| US20200218064A1 (en) * | 2017-07-11 | 2020-07-09 | Technische Universität Dresden | Arrangement and method for disturbance correction for imaging flow measuring processes |
| CN108613791A (en) * | 2018-05-29 | 2018-10-02 | 南京航空航天大学 | A kind of incident shock three-dimensional structure measurement apparatus and measurement method |
| CN110823498A (en) * | 2019-07-16 | 2020-02-21 | 中国人民解放军空军工程大学 | High-speed schlieren-based supersonic velocity separation area measuring device and measuring method |
| CN210937655U (en) * | 2019-11-22 | 2020-07-07 | 江苏锐通激光科技有限公司 | Adjusting device for light path/light deflection |
| CN113092056A (en) * | 2021-04-25 | 2021-07-09 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Method for measuring three-dimensional density field of hypersonic flow field |
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Application publication date: 20220802 |