CN113063560B - Flow field imaging measurement system and main system - Google Patents
Flow field imaging measurement system and main system Download PDFInfo
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- CN113063560B CN113063560B CN202110310940.0A CN202110310940A CN113063560B CN 113063560 B CN113063560 B CN 113063560B CN 202110310940 A CN202110310940 A CN 202110310940A CN 113063560 B CN113063560 B CN 113063560B
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- G—PHYSICS
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- 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
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Abstract
The invention provides a measuring system and a main system of flow field imaging, wherein the system comprises: light barrier, laser equipment, aircraft experimental model, and camera device; the light barrier is provided with a light-transmitting hole with a specified shape; the appointed shape is consistent with the vertical section shape of the flow field area to be measured of the aircraft experimental model; the light barrier is used for generating parallel light sources with specified shapes by using the parallel laser beams; the imaging device is used for acquiring imaging results of a flow field region to be measured of the aircraft experimental model. In the mode, the shape of the light passing hole of the light barrier can be changed according to the appearance of the experimental model of the aircraft and the vertical cross-section shape of the flow field area to be measured, so that the shape of the parallel light source is changed, the changing mode is more convenient and rapid, no additional design of complex optical elements is needed, the measuring efficiency is improved, the measuring cost is reduced, and the requirement of complex curved flow field measurement is met.
Description
Technical Field
The invention relates to the technical field of flow field imaging of an aircraft experimental model, in particular to a flow field imaging measurement system and a main system.
Background
The flow field characteristics near the surface of the high-speed aircraft have important influences on aerodynamic performance, structural design, thermal protection and the like of the aircraft, and imaging measurement is required to be carried out on the flow field area of the aircraft for the flow field characteristics near the surface of the high-speed aircraft. In the related art, for a planar flow field, a planar laser light source is generally adopted for measurement; for curved flow fields, it is generally necessary to design a specific optical element to generate a light source with a specific curvature, and measure a flow field with a specific curvature; however, for flow field measurement of various aircrafts with different shapes, special optical elements are required to be designed according to the specific geometric dimensions of each aircrafts, so that the measurement efficiency is low, the cost is high, and the universality is poor. In addition, the specific optical element cannot provide a light source with discontinuous curvature, and cannot meet the requirement of complex curved flow field measurement.
Disclosure of Invention
Therefore, the present invention is directed to a flow field imaging measurement system and a main system, so as to reduce the measurement cost, improve the measurement efficiency, and meet the requirement of complex curved flow field measurement.
In a first aspect, an embodiment of the present invention provides a measurement system for flow field imaging, the system comprising: light barrier, laser equipment, aircraft experimental model, and camera device; the light barrier is provided with a light-transmitting hole with a specified shape; the specified shape is consistent with the vertical cross-sectional shape of the flow field area to be measured of the aircraft experimental model; the light barrier is used for generating parallel light sources with specified shapes by using the parallel laser beams; wherein the parallel laser beam is generated by a laser device; the imaging device is used for acquiring an imaging result of a flow field region to be measured of the aircraft experimental model; the flow field area to be measured of the aircraft experimental model coincides with the parallel light source.
Further, the laser device comprises a laser, a beam expanding device and a collimation device; the laser, the beam expanding device and the collimation device are arranged on the same optical axis; the size of the beam expanding device and the size of the collimating device are respectively larger than the size of the flow field area to be measured; wherein the beam expanding device is positioned in the middle area of the laser and the collimating device; the beam expanding device is used for carrying out beam expanding treatment on the initial laser beam generated by the laser; the collimating device is used for carrying out collimation treatment on the initial laser beam after beam expansion to obtain parallel laser beams, wherein the size of the parallel laser beams is larger than that of the flow field area to be measured.
Further, the light barrier is placed perpendicular to the parallel laser beams; the parallel laser beams vertically irradiate on the light barrier, pass through the parallel laser beams of the light through holes, and form the parallel light source with the appointed shape consistent with the shape of the light through holes through the shape of the light through holes.
Further, the image pickup device includes a plurality of ordinary cameras; the plurality of common cameras are arranged above the flow field area to be measured of the aircraft experimental model; each common camera is responsible for shooting a designated area in a flow field area to be measured, so that the common camera can clearly focus and image each partial area; the total shooting area of all the common cameras covers the flow field area to be measured; the image pickup apparatus is also configured to: aiming at a plurality of areas of the calibration target surface, shooting images corresponding to each area by using a common camera; the calibration target surface is arranged on a flow field area to be measured of the aircraft experimental model; the shape of the calibration target surface is consistent with the shape of the flow field area to be measured; calibration points are arranged on the calibration target surface at equal intervals; and focusing the shot image of the designated area by using the common camera to determine the calibrated camera parameters of the common camera.
Further, the image pickup device comprises a light field camera; the light field camera is arranged at the position above the flow field region to be measured of the aircraft experimental model; the image pickup apparatus is also configured to: shooting a calibration target surface by using a light field camera to obtain an image of the calibration target surface; the calibration target surface is arranged on a flow field area to be measured of the aircraft experimental model; the shape of the calibration target surface is consistent with the shape of the flow field area to be measured; calibration points are arranged on the calibration target surface at equal intervals; and shooting images by using the light field camera, focusing different areas of the images, and determining calibrated camera parameters of the light field camera.
Further, the image pickup device is configured to: obtaining an imaging result of a flow field area to be measured of an aircraft experimental model by using a calibrated common camera; or acquiring an imaging result of the flow field region to be measured of the aircraft experimental model by using the calibrated light field camera.
Further, the aircraft experimental model comprises one or more flow field regions to be measured; the flow field area to be measured comprises a curved flow field area; the curvature of the curved flow field region includes one or more.
Further, the light barrier comprises one or more light through holes; each light aperture includes one or more designated shapes, the designated shapes being determined by the geometry of the experimental model of the aircraft.
In a second aspect, an embodiment of the present invention provides a main flow field imaging measurement system, where the main system includes the flow field imaging measurement system of any one of the first aspects, and further includes a wind tunnel device; the measuring system for flow field imaging is positioned in the wind tunnel device.
Further, the wind tunnel device is used for: an air flow is generated, and the flow of ambient air in actual flight is simulated by an experimental model of the aircraft.
The embodiment of the invention has the following beneficial effects:
The invention provides a measuring system and a main system of flow field imaging, wherein the system comprises: light barrier, laser equipment, aircraft experimental model, and camera device; the light barrier is provided with a light-transmitting hole with a specified shape; the specified shape is consistent with the vertical cross-sectional shape of the flow field area to be measured of the aircraft experimental model; the light barrier is used for generating parallel light sources with specified shapes by using the parallel laser beams; wherein the parallel laser beams are generated by a laser device; the imaging device is used for acquiring an imaging result of a flow field region to be measured of the aircraft experimental model; the flow field area to be measured of the aircraft experimental model coincides with the parallel light source. In the mode, the shape of the light passing hole of the light barrier can be changed according to the appearance of the experimental model of the aircraft and the vertical cross-section shape of the flow field area to be measured, so that the shape of the parallel light source is changed, the changing mode is more convenient and rapid, no additional design of complex optical elements is needed, the measuring efficiency is improved, the measuring cost is reduced, and the requirement of complex curved flow field measurement is met.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
In order to make the above objects, features and advantages of the present invention more comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are some embodiments of the invention and that other drawings may be obtained from these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of a curved surface sheet of a curved surface flow field according to an embodiment of the present invention;
FIG. 2 is a schematic plan view of a curved flow field according to an embodiment of the present invention;
FIG. 3 is a schematic plan view of a compressed corner flow field according to an embodiment of the present invention;
FIG. 4 is a schematic view of a curved sheet of a discontinuous curved flow field according to an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a flow field imaging measurement system according to an embodiment of the present invention;
FIG. 6 is a schematic view of a light barrier according to an embodiment of the present invention;
FIG. 7 is a schematic diagram illustrating generation of a parallel light source according to an embodiment of the present invention;
Fig. 8 is a schematic diagram of parameter calibration of a general camera according to an embodiment of the present invention;
fig. 9 is a schematic diagram of parameter calibration of a light field camera according to an embodiment of the present invention;
fig. 10 is a schematic view of a camera according to an embodiment of the present invention;
Fig. 11 is a schematic structural diagram of a measurement main system for flow field imaging according to an embodiment of the present invention.
Icon:
100-light barrier; 200-a laser device; 300-aircraft experimental model; 400-camera device; 201-a laser; 202-a beam expanding device; 203-a collimation device; 401-a normal camera; 402-a light field camera; a 10-flow field imaging measurement system; 20-wind tunnel device.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The flow field characteristics near the surface of the high-speed aircraft have important influences on aerodynamic performance, aircraft structural design, thermal protection and the like of the aircraft, and the flow field characteristics near the surface of the aircraft are researched and measured, so that basis can be provided for the aircraft design. The methods commonly used for measuring the structure of the supersonic/hypersonic flow field are numerous, such as schlieren, shadow, interference, particle image velocity field, filter Rayleigh scattering, nano-tracing planar laser scattering technology, laser-induced fluorescence and other methods. Because the supersonic/hypersonic flow field has obvious three-dimensional characteristics, the flow field test technology represented by the planar laser scattering technology can measure a certain partial section of the three-dimensional flow field by using a laser sheet. However, the main characteristic of this kind of technology is that the laser sheet is a planar light source. For real aircraft, the profile is typically curved, so that the flow around the aircraft also often has curved characteristics. For example, in order to measure the flow field characteristics near the missile, imaging measurement is required for the curved flow field of the missile (as shown in fig. 1), but a planar laser light source (as shown in fig. 2) is provided by a traditional method. The requirements for measuring the external flow field area of the real aircraft with the curved surface appearance cannot be met.
In order to realize curved flow field measurement aiming at the appearance of a specific aircraft, the key point is to generate a curved laser sheet light source meeting the measurement requirement and having geometric dimensions for flow field illumination. In the related art, it is generally necessary to design a specific optical element to generate a light source with a specific curvature, and measure a flow field with the specific curvature, wherein the curvature or shape of the light source generated by the specific optical element cannot be changed arbitrarily; for flow field measurement of various aircrafts with different shapes, special optical elements are required to be designed according to the specific geometric dimensions of each aircrafts, so that the measuring efficiency is low, the cost is high, and the universality is poor. In addition, this particular optical element does not provide a light source with discontinuous curvature; aiming at the discontinuous geometric curved surface appearance, such as a compressed corner flow field shown in fig. 3 or a relatively complex area flow field of an aircraft experimental model curved wing and a control surface shown in fig. 4, laser sheet light with discontinuous curvature cannot be provided through a specific optical element, and the requirement of complex curved surface flow field measurement cannot be met.
Based on the above, the flow field imaging measurement system and the main system provided by the embodiment of the invention can reduce the measurement cost, improve the measurement efficiency and meet the requirement of complex curved flow field measurement.
For the understanding of this embodiment, a flow field imaging measurement system disclosed in this embodiment of the present invention will be described in detail, as shown in fig. 5, and the system includes: a light barrier 100, a laser device 200, an aircraft experimental model 300, and a camera 400; the light blocking plate 100 is provided therein with a light passing hole of a prescribed shape; the specified shape is consistent with the vertical cross-sectional shape of the flow field area to be measured of the aircraft experimental model;
The light barrier can block laser, the shape of the light through hole arranged in the light barrier is determined by the cross-sectional shape of the flow field area to be measured of the aircraft experimental model to be measured, for example, the cross-sectional shape of the flow field area to be measured of the aircraft experimental model shown in fig. 4, the light barrier of the aircraft experimental model is shown in fig. 6, the white frame area in the figure is the light through hole with the specified shape, and the cross-sectional shape of the flow field area to be measured is consistent with the specified shape of the light through hole. Specifically, the geometric dimension (corresponding to the specified shape) of the laser sheet light (corresponding to the parallel light source) required to be illuminated can be determined according to the appearance of the aircraft experimental model and the flow field area to be measured; according to the geometry, a light barrier with light passing holes of the same geometry is manufactured. When the experimental model of the aircraft comprises a plurality of flow field areas to be measured, a plurality of light through holes can be formed in the same light blocking plate, and the shape of each light through hole is the same as the shape of the vertical section of the flow field area to be measured.
The light barrier is used for generating parallel light sources with specified shapes by using parallel laser beams; wherein the parallel laser beam is generated by a laser device; the imaging device is used for acquiring an imaging result of a flow field region to be measured of the aircraft experimental model; the flow field area to be measured of the aircraft experimental model coincides with the parallel light source.
In particular, a parallel laser beam, which may be an amplified light source, may be generated with a laser device; the vertical irradiation area of the parallel laser beam needs to cover the light-passing hole area, so that the parallel laser beam is vertically irradiated on the light barrier with the light-passing hole, and only the parallel light of the corresponding part of the shape of the light-passing hole can pass through the light barrier to form a parallel light source with a specified shape consistent with the shape of the light-passing hole. In addition, the minimum size of the slit of the light-passing hole is not smaller than 2mm in consideration of diffraction phenomenon of the parallel laser beam passing through the slit, and can be generally set to be 2mm-3mm, so that the curved laser sheet light has enough illumination thickness, and the diffraction effect of the light passing through the light-passing hole can be greatly reduced.
The light barrier and the laser device may then be positioned such that the parallel light source obtained through the light barrier coincides with the flow field region of the experimental model of the aircraft to be measured. The parallel light source is overlapped with the flow field area to be measured of the aircraft experimental model, so that the basic condition of flow field imaging is obtained, and at the moment, an imaging device can be utilized to acquire the imaging result of the flow field area to be measured of the aircraft experimental model in a photographing mode. The camera device generally comprises a plurality of cameras, the camera is used for directly shooting the flow field area to be measured of the aircraft experimental model, and the imaging result of the flow field area to be measured is obtained by processing the shot image.
The embodiment of the invention provides a flow field imaging measurement system, which comprises: light barrier, laser equipment, aircraft experimental model, and camera device; the light barrier is provided with a light-transmitting hole with a specified shape; the specified shape is consistent with the vertical cross-sectional shape of the flow field area to be measured of the aircraft experimental model; the light barrier is used for generating parallel light sources with specified shapes by using the parallel laser beams; wherein the parallel laser beams are generated by a laser device; the imaging device is used for acquiring an imaging result of a flow field region to be measured of the aircraft experimental model; the flow field area to be measured of the aircraft experimental model coincides with the parallel light source. In the mode, the shape of the light passing hole of the light barrier can be changed according to the appearance of the experimental model of the aircraft and the vertical cross-section shape of the flow field area to be measured, so that the shape of the parallel light source is changed, the changing mode is more convenient and rapid, no additional design of complex optical elements is needed, the measuring efficiency is improved, the measuring cost is reduced, and the requirement of complex curved flow field measurement is met.
Further, as shown in fig. 7, the laser apparatus 200 includes a laser 201, a beam expanding device 202, and a collimating device 203; the laser 201, the beam expanding device 202 and the collimation device 203 are arranged with the same optical axis; the size of the beam expanding device 202 and the size of the collimation device 203 are respectively larger than the size of the flow field area to be measured; wherein the beam expanding device 202 is positioned in the middle area of the laser 201 and the collimating device 203; the beam expanding device is used for carrying out beam expanding treatment on the initial laser beam generated by the laser; the collimating device is used for carrying out collimation treatment on the initial laser beam after beam expansion to obtain parallel laser beams; wherein the parallel laser beam has a size larger than the flow field area to be measured.
The light barrier is arranged perpendicular to the parallel laser beams; the parallel laser beams vertically irradiate on the light barrier, pass through the parallel laser beams of the light through holes, and form the parallel light source with the appointed shape consistent with the shape of the light through holes through the shape of the light through holes.
The beam expander can be a beam expander; the collimating means may be a collimating lens. Firstly, a laser 201 emits an initial laser beam to the direction of a beam expanding device, then the beam expanding device is used for expanding the initial laser beam emitted by the laser, and a collimation device is used for changing the initial laser beam after the beam expansion into a parallel laser beam; so that the parallel laser beam size can cover the size of the light-passing hole. The light barrier is placed perpendicular to the parallel laser beams as shown in fig. 7, and the parallel laser beams may be perpendicularly irradiated onto the light barrier with the light passing holes, and the parallel laser beams passing through the light passing holes form a parallel light source of a prescribed shape in conformity with the shape of the light passing holes. It should be noted that, the dimensions of the beam expanding device and the collimating device may be determined according to the flow field area to be measured and the size of the through-hole, so that the dimensions of the beam expanding device 202 and the collimating device are respectively larger than the dimension of the flow field area to be measured, and the dimensions of the parallel laser beams are simultaneously larger than the flow field area to be measured.
In the mode, no additional special optical element is required to be processed, and only the light barrier with a specific clear aperture is required to be manufactured, so that the measurement cost is reduced, and the measurement efficiency is improved. However, the method has the defects that the utilization efficiency of laser beam energy is low, and most of laser energy is blocked; in addition, there is a certain loss of beam quality, and it is inevitable that there is also a very small amount of diffracted light. But can meet the requirements of illumination flow field areas from flow field imaging measurement, and the method provides a rapid and convenient curved flow field illumination light source at the expense of light intensity and partial beam quality.
Further, as shown in fig. 8, the image capturing apparatus includes a plurality of normal cameras 401; a plurality of common cameras 401 are arranged at the upper position of the flow field region to be measured of the aircraft experimental model 300; each common camera is responsible for shooting a designated area in a flow field area to be measured, so that the common camera can clearly focus and image each partial area; the total shooting area of all the common cameras covers the flow field area to be measured; the image pickup apparatus is further configured to: aiming at a plurality of areas of the calibration target surface, shooting images corresponding to each area by using a common camera; the calibration target surface is arranged on a flow field area to be measured of the aircraft experimental model; the shape of the calibration target surface is consistent with the shape of the flow field area to be measured; calibration points are arranged on the calibration target surface at equal intervals; and focusing the shot image of the designated area by using the common camera to determine the calibrated camera parameters of the common camera.
For the measurement of curved surface flow field imaging, the traditional camera, namely the image acquired by the common camera, can deform and can not focus the whole curved surface clearly. In order to eliminate the influence of the problems of image deformation, inaccurate focusing and the like on imaging measurement, the parameters of a camera for imaging need to be calibrated and corrected. Specifically, in order to ensure the accuracy of parameter correction, a specific calibration target surface is manufactured according to the shape of the flow field area to be measured for parameter calibration of the camera during imaging measurement. The calibration target surface can be determined by means of organic glass or 3D printing and the like; the calibration points can be directly engraved in the calibration target surface, or the drawing with the calibration points can be stuck on the calibration target surface; the calibration target surface can be placed at a position consistent with the flow field area to be measured through a fixing mechanism; the calibration target surface is identical in shape to the curved flow field region to be measured, and as shown in fig. 8 (a), the calibration target surface may be disposed on the flow field region to be measured of the experimental model of the aircraft. In addition, the calibration target surface is provided with calibration points at equal intervals, for example, the calibration points may be arranged at equal intervals along the curved surface direction, or a checkerboard pattern of calibration target surfaces may be adopted, and the embodiment does not limit the pattern form of the calibration target surface.
As shown in fig. 8 (b), for curved surfaces, each camera can only image in a clear focusing way within a certain range, so that imaging of the whole flow field area to be measured can be realized by means of clear focusing of a plurality of cameras on different areas. Shooting different ranges respectively, and jointly combining to cover the whole flow field area to be measured; in addition, the camera calibration can realize focusing of the whole curved surface flow field when the camera images by focusing different areas in the calibration target surface by means of different cameras, so as to further determine the calibration camera parameters of the common camera.
Further, as shown in fig. 9, the image capturing apparatus includes a light field camera 402; the light field camera 402 is arranged at a position above a flow field region to be measured of the aircraft experimental model 300; the image pickup apparatus 400 is also configured to: shooting a calibration target surface by using a light field camera to obtain an image of the calibration target surface; the calibration target surface is arranged on a flow field area to be measured of the aircraft experimental model; the shape of the calibration target surface is consistent with the shape of the flow field area to be measured; calibration points are arranged on the calibration target surface at equal intervals; and shooting images by using the light field camera, focusing different areas of the images, and determining calibrated camera parameters of the light field camera.
For different adopted imaging cameras, a light field camera can be adopted for calibrating and imaging measurement of the camera, and the field camera has the capability of photographing before focusing, so that a plurality of cameras are not required to focus on different areas clearly. The mode of calibrating the target surface set up in the camera parameter of the above-mentioned calibration ordinary camera is the same, and will not be described here. As shown in fig. 9 (b), after capturing an image of the calibration target surface, clear focusing on different positions is achieved according to data post-processing, so as to reconstruct the image and further determine calibration camera parameters of the calibration light field camera.
By calibrating the camera parameters, image distortion caused by imaging can be eliminated.
Further, as shown in fig. 10, the image pickup apparatus is configured to: obtaining an imaging result of a flow field area to be measured of an aircraft experimental model by using a calibrated common camera; or acquiring an imaging result of the flow field region to be measured of the aircraft experimental model by using the calibrated light field camera.
Specifically, after the calibration target surface is removed, a beam expanding device and a collimation device are utilized to emit parallel laser beams, so that the collimation laser light source is used for illuminating the flow field area of the experimental model of the aircraft, and the position of the light barrier is reasonably arranged, so that the parallel light source passing through the light passing hole coincides with the flow field area to be measured. As shown in fig. 10 (a), an image of a flow field region to be measured of an experimental model of an aircraft is photographed using a normal camera whose calibration is completed, and the photographed image is post-processed. For a plurality of common cameras, the clearly focused flow field areas obtained by each camera are spliced to form a curved flow field imaging result. As shown in fig. 10 (b), the calibrated light field camera is used to capture images of the flow field region to be measured of the experimental model of the aircraft, and the imaging result of the curved flow field is reconstructed by resolving the images of different focusing planes.
In the mode, the common camera and the light field camera in the image pickup device are subjected to parameter calibration, so that the influence caused by imaging of the camera is eliminated, the image distortion caused by imaging is eliminated, and the imaging effect is improved.
Further, the aircraft experimental model comprises one or more flow field areas to be measured; the flow field area to be measured comprises a curved flow field area; the curvature of the curved flow field region includes one or more. The light barrier comprises one or more light through holes; each light-passing hole comprises one or more designated shapes, and the designated shapes are determined by the geometric shape of an aircraft experimental model; wherein each of the specified shapes may be in communication with each other.
In particular, if the experimental model of the aircraft includes one or more flow field regions to be measured, a plurality of light passing holes may be provided on the same light barrier. If the curvature of a curved flow field region includes one or more, as shown in fig. 4, the geometric curved discontinuous profile, that is, the experimental model of the aircraft includes one or more curved flow field regions with curvature, a light passing hole may be formed in the light barrier, including a plurality of designated shapes, and each of the designated shapes is mutually communicated. In the mode, curved laser with discontinuous curvature can be generated so as to meet the requirement of complex curved flow field measurement; also for example, L-shaped flow field regions include planar flow field regions having a discontinuous curvature.
In the mode, the flow field imaging measurement method which can rapidly generate the illumination light source aiming at the complex curved surface appearance and calibrate the curved surface flow field measurement area is more convenient and rapid in changing the geometric dimension of the curved surface laser, does not need to additionally design complex optical elements, and is lower in cost.
The embodiment of the invention also provides a main flow field imaging measurement system, as shown in fig. 11, which comprises a flow field imaging measurement system 10 and a wind tunnel device 20; the flow field imaging measurement system 10 is located in a wind tunnel device 20. The wind tunnel device is used for: an air flow is generated, and the flow of ambient air in actual flight is simulated by an experimental model of the aircraft.
Specifically, after each device in the flow field imaging measurement system is set, the flow field imaging measurement system 10 is located in the wind tunnel device 20, a wind tunnel is operated, existing technologies such as NPLS (New Power LIGHTING SYSTEM ) and PIV (PARTICLE IMAGE Velocimetry, particle image velocimetry) are used as bases, tracer particles are put in, a flow field area to be measured is illuminated by a parallel light source, and photographing imaging is performed by a camera. The obtained curved flow field imaging result can provide basis for later flow field characteristic research, and isoparametric analysis of speed, structure size and the like in the curved flow field.
The main flow field imaging measurement system provided by the embodiment of the invention has the same technical characteristics as the flow field imaging measurement system provided by the embodiment, so that the same technical problems can be solved, and the same technical effects can be achieved.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described system and apparatus may refer to corresponding procedures in the foregoing method embodiments, which are not described herein again.
In addition, in the description of embodiments of the present invention, unless explicitly stated and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood by those skilled in the art in specific cases.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Finally, it should be noted that: the above examples are only specific embodiments of the present invention for illustrating the technical solution of the present invention, but not for limiting the scope of the present invention, and although the present invention has been described in detail with reference to the foregoing examples, it will be understood by those skilled in the art that the present invention is not limited thereto: any person skilled in the art may modify or easily conceive of the technical solution described in the foregoing embodiments, or perform equivalent substitution of some of the technical features, while remaining within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention, and are intended to be included in the scope of the present invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.
Claims (8)
1. A measurement system for flow field imaging, the system comprising: light barrier, laser equipment, aircraft experimental model, and camera device;
the light barrier is internally provided with a light-transmitting hole with a specified shape; the specified shape is consistent with the vertical cross-sectional shape of the flow field area to be measured of the aircraft experimental model;
The light barrier is used for generating parallel light sources with the specified shape by using parallel laser beams; wherein the parallel laser beam is generated by the laser device;
The camera device is used for acquiring an imaging result of a flow field area to be measured of the aircraft experimental model; the flow field area to be measured of the aircraft experimental model coincides with the parallel light source;
Wherein the image pickup device comprises a plurality of common cameras; the common cameras are arranged above the flow field area to be measured of the aircraft experimental model; each common camera is responsible for shooting a designated area in the flow field area to be measured, so that the common camera can clearly focus and image each designated area; the total shooting area of all the common cameras covers the flow field area to be measured; the image pickup apparatus is further configured to: shooting images corresponding to a plurality of areas of a calibration target surface by using the common camera; the calibration target surface is arranged on a flow field area to be measured of the aircraft experimental model; the shape of the calibration target surface is consistent with the shape of the flow field area to be measured; the calibration target surface is provided with calibration points at equal intervals; focusing the shot image of the designated area by using the common camera, and determining the calibrated camera parameters of the common camera;
or alternatively;
The camera device comprises a light field camera; the light field camera is arranged above a flow field area to be measured of the aircraft experimental model; the image pickup apparatus is further configured to: shooting a calibration target surface by using a light field camera to obtain an image of the calibration target surface; the calibration target surface is arranged in a flow field area to be measured of the aircraft experimental model; the shape of the calibration target surface is consistent with the shape of the flow field area to be measured; the calibration target surface is provided with calibration points at equal intervals; and shooting the image by using the light field camera, focusing different areas of the image, and determining the calibrated camera parameters of the light field camera.
2. The system of claim 1, wherein the laser device comprises a laser, a beam expanding device, a collimating device;
The laser, the beam expanding device and the collimating device are arranged on the same optical axis; the size of the beam expanding device and the size of the collimating device are respectively larger than the size of the flow field area to be measured; wherein the beam expanding device is positioned in the middle area of the laser and the collimating device;
the beam expanding device is used for expanding the initial laser beam generated by the laser;
The collimating device is used for carrying out collimation treatment on the initial laser beam after beam expansion to obtain the parallel laser beam; wherein the parallel laser beams have a size larger than the flow field region to be measured.
3. The system of claim 2, wherein the light barrier is positioned perpendicular to the parallel laser beams;
The parallel laser beams vertically irradiate on the light barrier, pass through the parallel laser beams of the light through holes, and pass through the shapes of the light through holes to form a parallel light source with a specified shape consistent with the shapes of the light through holes.
4. The system of claim 1, wherein the imaging device is configured to: acquiring an imaging result of a flow field region to be measured of the aircraft experimental model by using a calibrated common camera; or acquiring an imaging result of the flow field region to be measured of the aircraft experimental model by using the calibrated light field camera.
5. The system of claim 1, wherein the aircraft experimental model comprises one or more flow field regions to be measured; the flow field area to be measured comprises a curved flow field area; the curvature of the curved flow field region includes one or more.
6. The system of claim 5, wherein the light barrier comprises one or more light-passing apertures; each of the light apertures includes one or more designated shapes determined by the geometry of the experimental model of the aircraft.
7. A flow field imaging measurement host system, characterized in that the host system comprises the flow field imaging measurement system of any one of claims 1-6, further comprising a wind tunnel device; the flow field imaging measurement system is positioned in the wind tunnel device.
8. The host system of claim 7, wherein the wind tunnel device is configured to: generating an air flow, and simulating the flow of surrounding air of the experimental model of the aircraft in actual flight.
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| CN115988342B (en) * | 2023-03-20 | 2023-07-07 | 中国空气动力研究与发展中心计算空气动力研究所 | Flow display image shooting device, method, system and medium |
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| CN108065481A (en) * | 2018-01-02 | 2018-05-25 | 顾效源 | A kind of Laser Curve scale |
| CN111623952A (en) * | 2020-04-29 | 2020-09-04 | 中国航天空气动力技术研究院 | Three-dimensional space flow field measuring device and method in sub-span wind tunnel |
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| CN111623952A (en) * | 2020-04-29 | 2020-09-04 | 中国航天空气动力技术研究院 | Three-dimensional space flow field measuring device and method in sub-span wind tunnel |
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