A three-dimensional endoscopic PIV probe integrating illumination and optical fiber imaging

Abstract

This invention belongs to the field of airflow field testing and optical measurement technology for aero-engine compressors, specifically relating to an integrated three-dimensional endoscopic PIV probe for measuring the internal flow field of aero-engines. It is suitable for three-dimensional velocity vector measurement of the internal flow field in confined spaces such as aero-engines, gas turbines, and industrial compressors. Its features include: an integrated probe body, a left imaging channel, a laser emission channel, a right imaging channel, an optical window, a spherical lens, a cylindrical lens, a fiber collimator, an optical fiber, an objective lens, an imaging fiber, an eyepiece, a purge channel, an air inlet, an air intake, an external connecting flange, an external laser interface, an external camera interface, an imaging camera, a laser, a displacement mechanism, and a target measurement area. The probe body contains a laser emission channel and left and right imaging channels arranged in a triangular pattern. Through single-hole installation, it can form sheet-like laser illumination in confined internal flow channels such as aero-engine compressors and simultaneously acquire dual-view particle images, thereby achieving high-precision measurement of the three-dimensional velocity components of the internal flow field.

Description

Technical Field

[0001] This invention belongs to the field of air compressor flow field testing and optical measurement technology for aero-engines. Specifically, it relates to an integrated three-dimensional endoscopic PIV probe for measuring the internal flow field of aero-engines, which is suitable for three-dimensional velocity vector measurement of the internal flow field in confined spaces such as aero-engines, gas turbines and industrial compressors. Background Technology

[0002] In the aerodynamic performance research of complex components such as compressors, turbines, and combustion chambers of aero-engines, the velocity distribution, unsteady flow structure, and turbulence characteristics within the flow field are key measurement parameters. Traditional particle image velocimetry (PIV) typically employs an "external" configuration, where tracer particles are introduced into the incoming flow, an externally positioned sheet laser illuminates the measurement area through a transparent window on the side wall, and an external camera records the image, thereby obtaining the velocity vector field within the measurement plane. Conventional PIV measurements usually require large transparent observation windows on the side wall or top cover of the measurement area, allowing the sheet laser beam and camera line of sight to pass through the wall and enter the blade passage from the outside. However, the casing, as a critical load-bearing component, has extremely stringent requirements for structural strength, airtightness, and contamination resistance. Establishing large optical windows would significantly weaken the integrity and load-bearing structure of the casing, posing significant safety hazards and often failing to meet the testing standards for the entire engine. Furthermore, the internal space of an engine is extremely compact, especially in the blade passage areas such as the adjustable guide vanes and stator blades of the compressor, where installation space is extremely limited, making it virtually impossible to physically install an observation window of the size required for conventional PIV.

[0003] On the other hand, the internal flow channels of engines are often designed as complex spatial curved surfaces. Machining flat glass windows on curved surfaces is extremely difficult; if curved windows are used to fit the shape of the flow channel, or if optical measurements are performed directly through the curved flow channel walls, complex refraction and reflection phenomena will occur as light passes through different medium interfaces. This will cause severe image distortion and laser sheet light path offset, leading to significant errors in velocity vector calculations, making the measurement data unable to accurately represent the actual flow field characteristics.

[0004] Patent CN118275729A proposes an endoscopic PIV, but it separates the illumination optical path from the imaging optical path, requiring the illumination probe and imaging probe to be inserted through two independent probe holes respectively, which increases the number of openings in the casing and can only realize two-dimensional flow field measurement.

[0005] Existing technologies lack a compact device capable of extending a probe hole into the flow channel while integrating laser illumination and dual-view imaging functions, thereby enabling three-dimensional velocity vector measurement under single-hole insertion conditions. To address this, a three-channel integrated stereo PIV probe for flow field measurement in aero-engine compressors, turbines, and other applications is proposed. This probe achieves single-probe stereo PIV measurement by arranging a laser emission channel and two imaging channels at a certain angle side-by-side within a single probe body. Summary of the Invention

[0006] The technical problem this invention aims to solve is: addressing the limitations of optical windows in existing components such as aero-engines, gas turbines, and industrial compressors, making it difficult to achieve three-dimensional PIV measurements through conventional window arrangements; and the fact that existing endoscopic PIV probes are mostly two-dimensional and unable to acquire three-dimensional velocity components. This invention proposes a three-channel integrated three-dimensional PIV probe for flow field measurement in components such as aero-engine compressors and turbines. This probe integrates laser illumination, left and right parallax imaging optical paths, and a start-up purging system within a single main body. It eliminates the need to modify the casing's large window, enabling precise three-dimensional measurement of the internal flow field through a single aperture.

[0007] The technical solution of this invention is:

[0008] A three-dimensional endoscopic PIV measurement probe integrating illumination and imaging is characterized by: an integrated probe body (1), a left imaging channel (2), a laser emission channel (3), a right imaging channel (4), optical windows (5), (6), and (7), a spherical lens (8), a cylindrical lens (9), an optical fiber collimator (10), an optical fiber (11), objective lenses (12) and (13), imaging optical fibers (14) and (15), eyepieces (16) and (17), a purge channel (18), an air inlet (19), an air intake (20), external connecting flanges (21), (22), (23), and (24), an external laser interface (25), an external camera interface (26) and (27), an imaging camera (28) and (29), a laser (30), a displacement mechanism (31), and a target measurement area (32). The integrated probe body (1) is the main support structure of the probe, and its shape is cylindrical with a diameter of 30~100mm and a length of 100~500mm. The integrated probe body (1) is made of stainless steel.

[0009] Furthermore, external connecting flanges (21), (22), (23), and (24) are fixed on the outer wall of the integrated probe body (1) to install and fix the entire probe to the mounting holes on the compressor or turbine casing wall, serving as a rigid connection and sealing interface between the probe and the mounting holes on the compressor casing wall.

[0010] Furthermore, three optically transmissive channels that are in a “pin” shape and penetrate through the integrated probe body (1) are precisely machined axially inside. The laser emission channel (3) is arranged above the geometric central axis of the integrated probe body (1), with an aperture of 5 - 20 mm. The left imaging channel (2) and the right imaging channel (4) are symmetrically distributed on both sides below the geometric central axis of the integrated probe body (1), with an aperture of 4 - 20 mm;

[0011] Furthermore, the laser emission channel (3) constitutes the illumination subsystem of the probe. The high - energy pulsed laser beam from an external laser (30) is coupled into the channel through the external laser interface (25) at the tail of the probe, transmitted by the optical fiber (11), and then converted into a collimated beam by the fiber collimator (10). It sequentially passes through the combination of a cylindrical lens (9) and a spherical lens (8) integrated in series inside for beam shaping. After beam expansion and focusing, it finally exits through the optical window (6) hermetically embedded in the center of the front end face of the probe, forming a high - brightness sheet - shaped illumination light in the flow field in front of the probe, thereby covering the target measurement area (32);

[0012] Furthermore, the left imaging channel (2) and the right imaging channel (4) together construct the stereoscopic imaging optical path of the probe. After the optical axes at the front ends of the two channels pass through their respective optical windows (5) and (7), the lines of sight converge towards the same target measurement area (32), and a preset stereoscopic parallax angle (10°~60°) is formed from the inside out. When the tracer particles in the target measurement area (32) are excited to generate scattered light, the light enters the probe through the optical windows (5) and (7) on both sides of the probe front end, and is first focused by the objective lens (12) and objective lens (13), respectively. The focused light signal is then coupled into the optical fibers (14) and (15) in the left imaging channel (2) and the right imaging channel (4), and is transmitted to the probe tail along their respective channels. At the probe tail, the image signal is exported by the image transmission fiber and then output through the adjustable eyepiece (16) and eyepiece (17), respectively. External camera interfaces (26) and (27) physically connect the left imaging channel (2) and the right imaging channel (4) to the high-resolution imaging cameras (28) and (29) respectively, so as to realize the synchronous acquisition of dual-view particle images. As another optional implementation, the left imaging channel (2) and the right imaging channel (4) can also use a lens combination composed of multiple lenses to transmit image signals. The scattered light of the tracer particles in the target measurement area (32) enters the imaging channel through the optical windows (5) and (7) respectively, and is collected by the objective lenses (12) and (13) to form an initial image. Then, through the relay lens group, collimating lens group, image-rotating lens group or other equivalent lens combination set in each imaging channel, the image signal is transmitted along the probe axis to the probe tail, and finally output to the imaging cameras (28) and (29) through the external camera interfaces (26) and (27) to realize the synchronous acquisition of dual-view particle images.

[0013] Furthermore, the integrated probe body (1) incorporates a purging system. The purging system includes a purging channel (18), an air inlet (19), and an air intake (20). High-pressure gas is sprayed through this channel to the optical windows (5), (6), and (7) at the front end to prevent oil or particles from adhering and affecting the optical transmission performance. Purging can be performed before or during the experiment. The air inlet (19) and the air intake (20) can be interchanged to achieve a better purging effect. The diameter of the air inlet (19) and the air intake (20) is 3~10mm. The radial dimension of the purging channel (18) along the probe is 1~5mm, and the circumferential angle is covered by 10°~140°.

[0014] Furthermore, the materials of the optical windows (5), (6), and (7) are preferably sapphire glass or other high-pressure and corrosion-resistant optical glass, which have the characteristics of high temperature resistance, high pressure resistance and particle erosion resistance, and are sealed and matched with the left imaging channel (2), laser emission channel (3), and right imaging channel (4) of the head of the integrated probe body (1).

[0015] Furthermore, the imaging cameras (28) and (29) and the laser (30) are linked by a synchronous control system. The dual-pulse laser illumination and the phase-locked triggering mode of the camera are used to acquire a time-dependent particle image sequence in the target measurement area (32), and the three-dimensional velocity vector field is reconstructed using a three-dimensional cross-correlation algorithm.

[0016] Furthermore, the displacement mechanism (31) is mechanically connected to the integrated probe body (1), which can drive the integrated probe body (1) to perform precise translational motion along the axial direction and circumferential rotational motion around the axis, thereby flexibly adjusting the spatial coordinates of the front target measurement area (32) inside the flow field; through this combination of axial feed and circumferential scanning motion, the probe can traverse the complex flow field inside the combustion chamber or compressor, obtain multi-section flow field information at different radial depths and circumferential angles, and realize large-scale scanning and measurement of the three-dimensional flow field structure.

[0017] The beneficial effects of this invention are:

[0018] To address the limitations of traditional external PIV probes in extremely compact space constraints for components such as aero-engines, gas turbines, and industrial compressors—namely, the difficulty in creating large windows, severe optical distortion in curved windows, and the technical bottlenecks of existing endoscopic techniques requiring multiple probe holes and limited to two-dimensional measurements—a three-channel integrated stereo PIV probe is proposed. This probe employs a single-hole integrated design, combining a laser illumination channel, two imaging channels at specific angles, and a purge channel into a single unit. It can extend into the flow channel through a single probe hole, achieving high-precision measurement of three-dimensional velocity vectors within a confined space while maintaining the structural integrity of the casing.

[0019] Beneficial effect 1:

[0020] The laser illumination system and a dual-imaging optical path with a specific parallax angle are encapsulated in a triangular configuration within the same body, requiring only standard probe holes on the equipment wall for functional deployment. This design effectively avoids the difficulties of traditional solutions that require large optical windows or complex external optical paths on the engine load-bearing casing, maximizing the structural integrity, airtightness, and overall rigidity of the test section wall. This allows for the successful completion of high-precision three-dimensional velocity vector measurements in areas with extremely limited physical space, such as the compressor stage space and blade passageways of aero-engines.

[0021] Benefit 2:

[0022] Compared to traditional methods that require inserting multiple single-function probes simultaneously to achieve the same three-dimensional measurement purpose, this device only requires small holes and flange sealing structures in localized areas of the wall, eliminating the need for multiple holes. By changing the probe's insertion depth within the flow channel through a displacement mechanism, the device can flexibly traverse and scan flow field regions at different radial positions, no longer limited to a single fixed measurement point, significantly expanding the measurement coverage of a single installation.

[0023] Benefit 3:

[0024] After the laser beam is shaped inside the probe, it is directly projected onto the flow field under test through the front window. The particle scattering signal is then extracted from the imaging channel by the endoscopic system to the external camera. Compared with traditional long-distance external optical path solutions, the integrated endoscopic design effectively reduces refraction distortion and stray light interference caused by light passing through multiple medium interfaces, significantly improving the signal-to-noise ratio and imaging quality of the particle image, thereby ensuring the authenticity and representativeness of the velocity field calculation results.

[0025] Beneficial effect four:

[0026] The probe integrates a pneumatic purging system, which directs high-pressure gas to the optical window surface of the probe head via an internal purging channel. The purging channel is completely embedded within the probe body, with no protruding nozzles or conduits on the probe head. This concealed flow channel design effectively removes oil and particles from the optical window surface using high-pressure gas, ensuring optical transmission performance, while maintaining the streamlined and smooth shape of the probe head. It avoids additional shock waves or wake interference caused by additional purging structures, ensuring the authenticity of the measured flow field and the accuracy of the measurement.

[0027] Benefit 5:

[0028] The complex geometric coupling between the sheet light plane generated by the laser emission channel and the focal planes of the left and right imaging channels has been precisely calibrated and locked during the probe manufacturing and assembly stage. At the test site, only the mechanical installation of the probe and the connection of external cables are required to conduct the test. This completely avoids the time-consuming and challenging coupling adjustment of the laser sheet light and the dual-camera field of view within the confined and complex test bench space of an aero-engine, greatly simplifying the testing process of the 3D PIV system and significantly reducing the technical threshold and time cost of testing. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of an integrated PIV probe according to an embodiment of the present invention.

[0030] Figure 2 This is a top view of an integrated PIV probe according to an embodiment of the present invention.

[0031] Figure 3 This is a sectional view of section AA.

[0032] Figure 4 This is a sectional view of section BB.

[0033] Figure 5 This is a cross-sectional view of section CC.

[0034] Figure 6 This is a sectional view of section DD.

[0035] Figure 7 This is a sectional view of section EE.

[0036] Figure 8 This is a schematic diagram illustrating a specific implementation of an integrated PIV probe inside a compressor according to an embodiment of the present invention.

[0037] Wherein: 1-Integrated probe body, 2-Left imaging channel, 3-Laser emission channel, 4-Right imaging channel, 5, 6, 7-Optical windows, 8-Spherical lens, 9-Cylindrical lens, 10-Fiber collimator, 11-Fiber optic cable, 12, 13-Objective lens, 14, 15-Imaging fiber optic cable, 16, 17-Eyepiece, 18-Purge channel, 19-Air inlet, 20-Air suction port, 21, 22, 23, 24-External connecting flange, 25-External laser interface, 26, 27-External camera interface, 28, 29-Imaging camera, 30-Laser, 31-Displacement mechanism, 32-Target measurement area. Detailed Implementation

[0038] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0040] like Figure 1 , Figure 2As shown in the figure, this embodiment introduces a three-dimensional endoscopic PIV measurement probe integrating illumination and imaging, which mainly consists of an integrated probe body (1), a left imaging channel (2), a laser emission channel (3), a right imaging channel (4), optical windows (5), (6), and (7), a spherical lens (8), a cylindrical lens (9), objective lenses (12) and (13), optical fibers (14) and (15), eyepieces (16) and (17), a purge channel (18), an air inlet (19), an air intake (20), external connecting flanges (21), (22), (23), and (24), an external laser interface (25), and external camera interfaces (26) and (27). The integrated probe body (1) is the main support structure of the probe, cylindrical in shape with a diameter of 50 mm and a length of 300 mm. The integrated probe body (1) is made of stainless steel.

[0041] The relative positions and structures of the probe's internal optical channels and purge channels are as follows: Figure 3 , Figure 4 As shown. The integrated probe body (1) integrates a laser emission channel (3) and imaging channels (2) and (4) for light transmission, as well as a purge channel (18). In terms of specific layout, the laser emission channel (3) is coaxially set at the geometric center of the cross-section of the integrated probe body (1), with an aperture of 10 mm; the left imaging channel (2) and the right imaging channel (4) are symmetrically distributed about the central laser channel as the axis of symmetry, close to the probe centerline, with an aperture of 8 mm, forming a compact core optical area.

[0042] The probe imaging system, laser system, and purge system, as well as... Figure 5 , Figure 6 , Figure 7As shown. The laser emission system is located above the central axis of the probe, and the external laser interface (25) is connected to the laser emission channel (3). The laser beam enters from the bottom, is transmitted by the optical fiber (11), and is then converted into a collimated beam by the optical fiber collimator (10). It then passes through the cylindrical lens (9) and spherical lens (8) integrated in series in the channel to complete the beam shaping, expansion and focusing. Finally, it is projected onto the flow field to be measured through the optical window (6) sealed in the center of the front end, forming a sheet-like illumination light. The imaging subsystem includes two symmetrical optical paths, located on both sides below the central axis of the probe. Optical windows (5) and (7) are respectively installed at the front ends of the left imaging channel (2) and the right imaging channel (4). Scattered light from particles in the flow field enters through the windows and is first focused by the objective lens (12) and objective lens (13). The focused light signal then enters the optical fibers (14) and (15) in the left imaging channel (2) and the right imaging channel (4) to transmit the image signal and output it. Then it is output through the adjustable eyepiece (16) and eyepiece (17) respectively, and finally physically docked with the imaging camera through the external camera interface (26) and (27). The purging system is mainly composed of a longitudinally penetrating purging channel (18). High-pressure clean gas is introduced through the air inlet (19) at the bottom, transported to the head along the channel, and ejected at high speed from the micro nozzles around the optical window to achieve the purging cleaning effect. The gas is then discharged through the negative pressure suction port (20). The diameter of the air inlet (19) and the suction port (20) is 3 mm.

[0043] The specific implementation scheme of this probe inside the compressor is as follows: Figure 8 As shown. The integrated probe body (1) penetrates the single probe hole reserved on the compressor casing wall and extends into the flow channel. It is rigidly fixed to the casing wall and hermetically sealed using external connecting flanges (21), (22), (23), and (24). Before the experiment, the air inlet (19) and air intake (20) are connected to the external air source system to clean the optical windows (5), (6), and (7) on the probe head. The external laser interface (25) at the probe tail is connected to the laser (30) through the optical guide arm, and the external camera interfaces (26) and (27) are connected to two imaging cameras (28) and (29) respectively through fiber optic bundles. The displacement mechanism (31) is mechanically coupled to the integrated probe body (1) and can drive the probe to precisely move along the axial direction and rotate circumferentially within the mounting hole, thereby flexibly adjusting the front-end detection position. During the test, the laser beam is projected through the probe to form a sheet-like target measurement area (32) that cuts into the main flow direction of the compressor at the front end. When the tracer particles pass through the light sheet with the mainstream, they are scattered. Under the phase-locking trigger of the synchronous controller, the two imaging cameras (28) and (29) synchronously acquire the particle image sequence through the internal optical path of the probe. Finally, the three-dimensional cross-correlation algorithm is combined to solve the image and reconstruct a high-precision three-dimensional velocity vector field in the confined space.

[0044] This invention describes a three-dimensional endoscopic PIV measurement probe integrating illumination and imaging. It employs a highly integrated design of laser illumination and dual-view imaging optical paths, tightly sealing the dual imaging channels and laser emission channel within a single probe substrate, and embedding a pneumatic purging system for self-cleaning of the optical window. In practical applications for space flow field testing in aero-engines, gas turbine compressors, etc., this probe abandons the traditional approach of using large observation windows or multiple apertures, penetrating deep into the flow channel only through a single probe hole in the casing wall. The probe's depth and angle within the measurement area can be adjusted via a displacement mechanism, thereby achieving more extensive and flexible precise measurement of three-dimensional velocity vectors within confined spaces while ensuring the structural integrity and airtightness of the equipment.

Claims

1. An integrated illumination and imaging three-dimensional endoscopic PIV measurement probe, characterized by: Integrated probe body (1), left imaging channel (2), laser emission channel (3), right imaging channel (4), optical windows (5), (6), (7), spherical lens (8), cylindrical lens (9), fiber optic collimator (10), optical fiber (11), objective lenses (12), (13), imaging optical fibers (14), (15), eyepieces (16), (17), purge channel (18), air inlet (19), suction port (20), external connection flanges (21), (22), (23), (24), external laser interface (25), external camera interfaces (26), (27), imaging cameras (28), (29), laser (30), displacement mechanism (31) and target measurement area (32). The integrated probe body (1) is the main support structure of the probe, with a cylindrical shape, a diameter of 30 - 100 mm, and a length of 100 - 500 mm. The integrated probe body (1) is made of stainless steel material; Further, the external connection flanges (21), (22), (23), (24) are fixed on the outer wall of the integrated probe body (1) and are used to install and fix the entire probe to the mounting hole positions on the compressor or turbine casing wall surface, serving as a rigid connection and sealing interface between the probe and the mounting hole positions on the compressor casing wall surface; Further, three axially precision - machined and through optical transmission channels in a "pin" shape are formed inside the integrated probe body (1). The laser emission channel (3) is arranged above the geometric central axis of the integrated probe body (1), with a pore diameter of 5 - 20 mm. The left imaging channel (2) and the right imaging channel (4) are symmetrically distributed on both sides below the geometric central axis of the integrated probe body (1), with a pore diameter of 4 - 20 mm; Further, the laser emission channel (3) constitutes the illumination subsystem of the probe. The high - energy pulsed laser beam from the external laser (30) is coupled into the channel through the external laser interface (25) at the tail of the probe, transmitted by the optical fiber (11), then transformed into a collimated beam by the fiber optic collimator (10), and sequentially passes through the combination of the internally serially integrated cylindrical lens (9) and spherical lens (8) for beam shaping. After beam expansion and focusing, it finally exits through the optical window (6) hermetically embedded in the center of the front end face of the probe, forming a high - brightness sheet - shaped illumination light in the flow field in front of the probe, thus covering the target measurement area (32); Furthermore, the left imaging channel (2) and the right imaging channel (4) together construct the stereoscopic imaging optical path of the probe. After the optical axes at the front ends of the two channels pass through their respective optical windows (5) and (7), the lines of sight converge towards the same target measurement area (32), and a preset stereoscopic parallax angle (10°~60°) is formed from the inside out. When the tracer particles in the target measurement area (32) are excited to generate scattered light, the light enters the probe through the optical windows (5) and (7) on both sides of the probe front end, and is first focused by the objective lens (12) and objective lens (13), respectively. The focused light signal is then coupled into the optical fibers (14) and (15) in the left imaging channel (2) and the right imaging channel (4), and is transmitted to the probe tail along their respective channels. At the probe tail, the image signal is exported by the image transmission fiber and then output through the adjustable eyepiece (16) and eyepiece (17), respectively. External camera interfaces (26) and (27) physically connect the left imaging channel (2) and the right imaging channel (4) to the high-resolution imaging cameras (28) and (29) respectively, so as to realize the synchronous acquisition of dual-view particle images. As another optional implementation, the left imaging channel (2) and the right imaging channel (4) can also use a lens combination composed of multiple lenses to transmit image signals. The scattered light of the tracer particles in the target measurement area (32) enters the imaging channel through the optical windows (5) and (7) respectively, and is collected by the objective lenses (12) and (13) to form an initial image. Then, through the relay lens group, collimating lens group, image-rotating lens group or other equivalent lens combination set in each imaging channel, the image signal is transmitted along the probe axis to the probe tail, and finally output to the imaging cameras (28) and (29) through the external camera interfaces (26) and (27) to realize the synchronous acquisition of dual-view particle images. Furthermore, the integrated probe body (1) incorporates a purging system. The purging system includes a purging channel (18), an air inlet (19), and an air intake (20). High-pressure gas is sprayed through this channel to the optical windows (5), (6), and (7) at the front end to prevent oil or particles from adhering and affecting the optical transmission performance. Purging can be performed before or during the experiment. The air inlet (19) and the air intake (20) can be interchanged to achieve a better purging effect. The diameter of the air inlet (19) and the air intake (20) is 3~10mm. The radial dimension of the purging channel (18) along the probe is 1~5mm, and the circumferential angle is covered by 10°~140°. Furthermore, the materials of the optical windows (5), (6), and (7) are preferably sapphire glass or other high-pressure and corrosion-resistant optical glass, which have the characteristics of high temperature resistance, high pressure resistance and particle erosion resistance, and are sealed and matched with the left imaging channel (2), laser emission channel (3), and right imaging channel (4) of the head of the integrated probe body (1). Furthermore, the imaging cameras (28) and (29) and the laser (30) are linked by a synchronous control system. The dual-pulse laser illumination and the phase-locked triggering mode of the camera are used to acquire a time-dependent particle image sequence in the target measurement area (32), and the three-dimensional velocity vector field is reconstructed using a three-dimensional cross-correlation algorithm. Furthermore, the displacement mechanism (31) is mechanically connected to the integrated probe body (1), which can drive the integrated probe body (1) to perform precise translational motion along the axial direction and circumferential rotational motion around the axis, thereby flexibly adjusting the spatial coordinates of the front target measurement area (32) within the flow field; through this combination of axial feed and circumferential scanning motion, the probe can traverse the complex flow field inside the combustion chamber or compressor, obtain multi-section flow field information at different radial depths and circumferential angles, and realize large-scale scanning and measurement of the three-dimensional flow field structure.

Images