An anti-pollution laser introduction device

Abstract

The present invention belongs to the technical field of internal flow aerodynamic optical measurement, and discloses an anti-pollution laser introduction device. The anti-pollution laser introduction device of the present invention includes a device main body and a protective air curtain generation system; the laser of an external laser is conditioned by the lens group of the device main body and travels along the central axis of the optical path channel, and finally is reflected and exported by a reflector, and irradiates a to-be-measured flow field of a closed air flow channel or pipeline with a housing such as an aeroengine. The high-pressure gas source of the protective air curtain generation system ejects high-pressure air flow through an annular gap, and the high-pressure air flow is affected by the to-be-measured flow field to form a high-speed air curtain around the reflector. The high-speed air curtain can deflect the pollution source carried in the to-be-measured air flow from the mirror surface of the end reflector, protecting the reflector from pollution, thereby ensuring the quality of the introduced laser light source. The anti-pollution laser introduction device of the present invention is applicable to carrying out optical measurement experiments inside a closed air flow channel or pipeline with a housing such as an aeroengine.

Description

Technical Field

[0001] The present invention belongs to the technical field of internal flow aerodynamic optical measurement, and particularly relates to an anti-pollution laser introduction device. Background Art

[0002] Lasers have the advantages of high brightness, good directivity, and good monochromaticity, and are often used as light sources for optical measurement experiments, such as optical measurement experiments like particle image velocimetry (PIV), planar laser-induced fluorescence technique (PLIF), laser profilometry (LP), and flow visualization technique (FV), which have promoted the rapid development of optical measurement techniques.

[0003] When conducting experimental research on flow field optical measurement using techniques such as PIV and PLIF, it is necessary to first uniformly disperse flow field tracer particles in the flow field, and then guide the laser light source to the specified measurement section. By taking pictures of the illuminated (or excited) tracer particle images, the distribution characteristics of flow field parameters such as relevant velocity, concentration, and temperature of the measurement section can be obtained. Commonly used tracer particles in PIV experiments include solid powders such as titanium dioxide and aluminum oxide, as well as micro-droplets such as dioctyl sebacate (DEHS). Commonly used tracer particles in PLIF experiments include rhodamine 6G (for concentration measurement), rhodamine B (for temperature measurement), and sodium dihydrogen phosphate phosphor (for temperature or concentration measurement).

[0004] However, when applying PIV and PLIF techniques to conduct internal flow field measurement experiments in aero-engines or other air ducts, two types of technical problems are usually encountered. One is the problem of introducing the laser light source affected by the occlusion of the pipe wall, casing, or blade. The other is the problem of the tracer substances required for PIV and PLIF measurements contaminating the laser light source. These two types of technical problems are the key factors restricting the efficiency of internal flow PIV and PLIF measurement experiments and even determining the success or failure of the experiments.

[0005] Currently, there is an urgent need to develop an anti-pollution laser introduction device. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art in the internal flow aerodynamic optical measurement technology such as aero-engines, and provide an anti-pollution laser introduction device.

[0007] The anti-pollution laser introduction device of the present invention is characterized in that the anti-pollution laser introduction device includes a device main body and a protective air curtain generation system;

[0008] The main body of the device is a three-stage stepped pipe body connected in sequence from top to bottom. The outer diameter of the three-stage stepped pipe body decreases sequentially from top to bottom. The top end of the stepped pipe body I is a laser access port, and a circular cavity is arranged inside the stepped pipe body I. The outer surface of the stepped pipe body II is provided with a mounting thread. The stepped pipe body III is a probing support rod. The inner cavity pipes of the stepped pipe body II and the stepped pipe body III are vertically connected and have the same inner diameter, jointly forming a support rod cavity, and the support rod cavity is communicated with the circular cavity of the stepped pipe body I. A light pipe is sleeved inside the support rod cavity. The light pipe is successively a cylindrical section and an extension section from top to bottom. The cylindrical section is located inside the support rod cavity, and the extension section extends out of the support rod cavity. A support platform is arranged on the extension section, and a reflecting mirror is installed on the support platform. The outer diameter of the light pipe is smaller than the inner diameter of the support rod cavity, and an annular gap is arranged between the light pipe and the stepped pipe body II and the stepped pipe body III. The central axes of the three-stage stepped pipe body, the circular cavity, the support rod cavity and the light pipe coincide with the central axis of the main body of the device. Inside the light pipe is an optical path channel, and a lens group is installed inside the optical path channel. The lens group includes a plurality of lenses arranged along the optical path channel.

[0009] The external laser is connected to the laser access port. The laser emitted by the laser is conducted and modulated through the lens group, and finally reflected and exported by the reflecting mirror to irradiate the flow field to be measured.

[0010] The described protective air curtain generating system includes an external high-pressure gas source, a high-pressure pipeline communicated with the high-pressure gas source and an annular gap. The high-pressure pipeline is inserted into the circular cavity from the side wall of the stepped pipe body I and communicated with the annular gap. At the outlet of the annular gap, the position blocked by the extension section is welded and sealed, and the position of the laser outlet is reserved as the high-pressure gas outlet.

[0011] The high-pressure gas flow from the high-pressure gas source is ejected through the high-pressure pipeline. The jet velocity of the high-pressure gas flow at the outlet of the annular gap is v 1 ; The included angle between the outlet end face of the cylindrical section of the light pipe and the marginal line of the reflected light of the reflecting mirror is θ 1 ; Affected by the gas flow velocity v 0 of the flow field to be measured, a high-speed air curtain with a synthetic velocity of v 2 is formed. The deflection angle of the high-speed air curtain relative to the central axis of the main body of the device, that is, the jet velocity v 1 of the high-pressure gas outlet is θ 2 ; When θ 2 ≤ (90° - θ 1 ), the high-speed air curtain makes the impurities carried in the gas flow of the flow field to be measured deviate from the mirror surface of the end reflecting mirror at a speed v 2 to protect the reflecting mirror from contamination.

[0012] Further, the pressure range of the high-pressure gas source is 0.2 MPa to 0.25 MPa, and the jet velocity of the high-pressure air flow v 1 ≤ 100 m / s.

[0013] Further, the materials of the device main body, the light pipe and the high-pressure pipeline are stainless steel.

[0014] Further, the outer diameter range of the inserted support rod is 8 mm to 20 mm.

[0015] Further, the included angle between the mirror surface of the reflecting mirror and the central axis of the device main body is 45°.

[0016] The anti-pollution laser guiding device of the present invention adjusts the circular beam of an external laser through the lens group of the device main body and travels along the central axis of the optical path channel, and finally is reflected and led out by the reflecting mirror, and irradiates the flow field to be measured in a closed air flow channel or pipeline with a housing such as an aero-engine. The flow velocity of the flow field to be measured is v 0 ; The high-pressure gas source of the protective air curtain generation system ejects high-pressure air flow through the annular gap, and the outlet velocity of the high-pressure air flow is v 1 , the outlet direction of the high-pressure air flow is parallel to the central axis of the device main body, and affected by the flow velocity of the flow field to be measured v 0 The high-pressure air flow forms a high-speed air curtain with a velocity of v 2 around the reflecting mirror, and the included angle between the high-speed air curtain and the central axis of the device main body is θ 2 . When the deflection angle of the high-speed air curtain satisfies θ 2 ≤ (90° - θ 1 ), the high-speed air curtain can make the pollution source carried in the flow to be measured deviate from the mirror surface of the end reflecting mirror at a velocity of v 2 to protect the reflecting mirror from pollution, thus ensuring the quality of the imported laser light source.

[0017] The anti-pollution laser guiding device of the present invention has the following characteristics:

[0018] a. By means of the inserted support rod, the lens group and the reflecting mirror, a laser light source is imported inside an air flow channel with a closed structure such as an aero-engine;

[0019] b. The high-speed air curtain formed by the protective air curtain generation system isolates the mirror surface of the reflecting mirror from the pollution source, forming a stable and high-quality laser light source;

[0020] c. The annular slit jet velocity ≤ 100 m / s, which is suitable for experimental measurements of the flow field velocity to be measured ≤ 100 m / s;

[0021] d. The probe-type support rod is installed in the casing of the aero-engine to be measured or other air flow pipelines through the installation thread. The probe-type support rod is small in size and is usually placed downstream of the flow field to be measured. The annular slit jet air flow deflects downstream of the flow field to be measured under the action of the flow velocity of the air flow to be measured. Therefore, the influence on the flow field to be measured is small.

[0022] The anti-pollution laser introduction device of the present invention has less interference on the flow field to be measured. The introduced high-quality laser can penetrate into closed air flow channels or pipelines with casings such as aero-engines. The high-speed air curtain on the cylindrical surface can isolate foreign matters such as water vapor, dust and tracer particles with a velocity ≤ 100 m / s in the air flow to be measured to avoid pollution of the light-emitting position of the laser light source, and is suitable for carrying out optical measurement experiments in the casing of an aero-engine or similar air flow pipelines. Description of the Drawings

[0023] Figure 1a It is a schematic structural diagram (sectional view) of the anti-pollution laser introduction device of the present invention;

[0024] Figure 1b It is a schematic structural diagram (top view) of the anti-pollution laser introduction device of the present invention;

[0025] Figure 1c It is a schematic structural diagram (bottom view) of the anti-pollution laser introduction device of the present invention;

[0026] Figure 2 It is a partial enlarged view of the end and a schematic diagram of the air flow velocity of the anti-pollution laser introduction device of the present invention.

[0027] In the figure, 1. light pipe; 2. lens group; 3. mirror; 4. annular slit; 5. laser access port; 6. installation thread; 7. probe-type support rod. Embodiment

[0028] The present invention will be described in detail below with reference to the drawings and embodiments.

[0029] Embodiment 1

[0030] As Figures 1a - 1c shown, the outer diameter of the probe-type support rod 7 in this embodiment is 15 mm, the wall thickness is 1 mm, the outer diameter of the light pipe 1 is 12 mm, the inner diameter of the optical path channel is 10 mm, the width of the annular slit 4 is 0.5 mm, and the diameter of the lens group 2 is 12 mm; the upper end of the light pipe 1 is welded to the bottom surface of the circular cavity through a cover plate with a thickness of 1 mm, and the lower end outlet of the light pipe 1 is locally welded to the probe-type support rod 7, so that the position of the annular slit 4 blocked by the extension section is locally closed, and the position of the laser outlet is reserved as the high-pressure air outlet.

[0031] The laser access port 5 is connected to an external laser light source, and the circular light beam generated by the external laser light source is ensured to exit along the central axis of the optical path channel after being conditioned by the lens group 2 through strict geometric tolerances. As Figure 2 shown, a 45° slope is machined on the support platform, and a mirror 3 with a diameter of 10 mm is adhesively installed on the slope with glass glue. The mirror surface of the mirror 3 forms a 45° angle with the central axis of the device body. The mirror 3 reflects the laser beam emitted by the lens group 2 to form a laser light source for irradiating the flow field to be measured.

[0032] The probing support rod 7 is fixed on the casing of the measured aeroengine or other air ducts through the mounting thread 6 with a diameter of 24 mm on the outer surface of the stepped tube body II, and the light-emitting position of the support platform is probed into the interior of the measured duct, realizing the idea of introducing a laser light source inside a closed air flow channel or duct with a casing such as an aeroengine.

[0033] The outer diameter of the high-pressure pipe is 3 mm. The high-pressure pipe is inserted into the circular cavity from the side wall of the stepped tube body I and communicates with the annular gap 4. The high-pressure air flows out from the annular gap 4, and the outlet jet velocity of the high-pressure air flow is v 1 . The included angle between the outlet end face of the columnar section of the light pipe 1 and the marginal line of the reflected light of the mirror 3 is θ 1 , θ 1 = 45°; affected by the air flow velocity v 0 of the flow field to be measured, a high-speed air curtain with a combined velocity of v 2 is formed. The deflection angle of the high-speed air curtain relative to the central axis of the device body, i.e., the outlet jet velocity v 1 of the high-pressure air flow, is θ 2 ; when θ 2 ≤ 45° (i.e., v 0 ≤ v 1 ), the high-speed air curtain can make the impurities carried in the air flow of the flow field to be measured deviate from the mirror surface of the end mirror 3 at a speed v 2 to protect the mirror 3 from contamination.

[0034] In this embodiment, the outlet jet velocity of the high-pressure air flow in the annular gap 4 is v 1 ≤ 100 m / s, which is applicable to the air flow velocity v 0Experimental measurements of ≤ 100 m / s.

[0035] The outer diameter of the inserted support rod 7 in this embodiment is 15 mm, belonging to a micro-miniature inserted structure. In addition, since the inserted support rod 7 is located downstream of the flow field to be measured, and the jet airflow in the annular gap deflects downstream under the action of the flow velocity of the airflow to be measured, the inserted support rod 7 has less interference on the flow field to be measured.

[0036] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. For those skilled in the art, without departing from the principle of the present invention, all the features disclosed in the present invention, or all the steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way. The present invention is not limited to the specific details and the illustrated examples here.

Claims

1. An anti-pollution laser introduction device, characterized in that, The anti-pollution type laser introduction device described above includes a device main body and a protective air curtain generation system; The device main body is a three-stage stepped pipe body connected in sequence from top to bottom, and the outer diameter of the three-stage stepped pipe body decreases sequentially from top to bottom; the top end of the stepped pipe body I is a laser access port (5), and a circular cavity is arranged inside the stepped pipe body I; an installation thread port (6) is arranged on the outer surface of the stepped pipe body II; the stepped pipe body III is a probing support rod (7); the inner cavity pipelines of the stepped pipe body II and the stepped pipe body III are vertically connected and have the same inner diameter, jointly forming a support rod cavity, and the support rod cavity is communicated with the circular cavity of the stepped pipe body I; an optical tube (1) is sleeved inside the support rod cavity, and the optical tube (1) is successively a column section and an extension section from top to bottom. The column section is located inside the support rod cavity, and the extension section extends out of the support rod cavity. A support platform is arranged on the extension section, and a reflecting mirror (3) is installed on the support platform; the outer diameter of the optical tube (1) is smaller than the inner diameter of the support rod cavity, and an annular gap (4) is arranged between the optical tube (1) and the stepped pipe body II and the stepped pipe body III; the central axes of the three-stage stepped pipe body, the circular cavity, the support rod cavity and the optical tube (1) coincide with the central axis of the device main body; an optical path channel is arranged inside the optical tube (1), and a lens group (2) is installed in the optical path channel. The lens group (2) includes several lenses arranged along the optical path channel; An external laser is connected to the laser access port (5), and the laser emitted by the laser is conducted and modulated through the lens group (2), and finally reflected and exported by the reflecting mirror (3) to irradiate the flow field to be measured; The protective air curtain generation system described above includes an external high-pressure gas source, a high-pressure pipeline communicated with the high-pressure gas source and an annular gap (4). The high-pressure pipeline is inserted into the circular cavity from the side wall of the stepped pipe body I and communicated with the annular gap (4); at the outlet of the annular gap (4), the position blocked by the extension section is welded and sealed, and the position of the laser outlet is reserved as the high-pressure air flow outlet; The high-pressure air flow of the high-pressure air source is ejected through the high-pressure pipeline, and the jet velocity of the high-pressure air flow at the outlet of the annular gap (4) is v 1 ; the included angle between the outlet end face of the cylindrical section of the light pipe (1) and the marginal line of the reflected light of the reflector (3) is θ 1 ; the high-pressure air flow is affected by the air flow velocity v 0 of the flow field to be measured, and a high-speed air curtain with a combined velocity of v 2 is formed. The deflection angle of the high-speed air curtain relative to the central axis of the device body, that is, the outlet jet velocity v 1 of the high-pressure air flow, is θ 2 ; when θ 2 ≤ (90° - θ 1 ), the high-speed air curtain causes the impurities carried in the air flow of the flow field to be measured to deviate from the mirror surface of the end reflector (3) at a speed v 2 to protect the reflector (3) from contamination.

2. The anti-pollution laser introduction device according to claim 1, wherein, The pressure range of the described high-pressure gas source is 0.2 MPa to 0.25 MPa, and the jet velocity of the high-pressure air flow v 1 ≤ 100 m / s.

3. The anti-pollution laser introduction device according to claim 1, wherein, The materials of the device main body, the optical tube (1) and the high-pressure pipeline are stainless steel.

4. The anti-pollution laser introduction device according to claim 1, wherein The outer diameter range of the probing support rod (7) is 8 mm to 20 mm.

5. The anti-pollution laser introduction device according to claim 1, characterized in that, The included angle between the mirror surface of the reflecting mirror (3) and the central axis of the device main body is 45°.

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