Parametric non-diffraction excitation device for high-speed flow field spectroscopy

Abstract

The non-diffraction excitation device for parameters of high-speed flow field spectrum disclosed in the present invention relates to the technical field of ultrafast excitation methods for spectra in high-speed fields, and solves the problem that in high-temperature and high-speed flow fields, due to the high-speed flow rate, the high-energy laser beam has a short action time, and the particles fail to absorb enough energy and cannot achieve atomic transition and emit spectrum, and cannot capture the spectrum information of the particles in the high-speed flow field. A three-level non-diffraction beam generator is used, the first level converges the high-energy excitation beam to provide excitation energy for the spectrum of the particles; the second and third levels form a potential difference through the auxiliary laser beam to achieve spatial confinement of the particles, and even if the particles are running at high speed, the non-diffraction cavity formed by the laser beam can capture the particles.

Description

Technical Field

[0001] The invention belongs to the technical field of laser excitation of particles in a high-temperature and high-speed flow field to identify the type of particles, and in particular relates to a parameter non-diffraction excitation device for a high-speed flow field spectrum. Background Art

[0002] With the rapid development of modern science and technology, optical analysis methods have been widely used in military research to observe and analyze some key parameters of high-temperature and high-speed flow fields. For example, the United States, the Soviet Union and other countries have conducted research on the radiation characteristics of missile tail flames, using the gas radiation in the tail flame to achieve optical reconnaissance, monitoring and precision strikes on various aircraft; for the non-steady-state combustion field of pulse detonation engines, the laser absorption spectroscopy technology in the optical non-contact measurement method is used to achieve synchronous online monitoring of the combustion field gas temperature, velocity and multi-component concentration. The detection and identification of spectral radiation characteristics in high-temperature and high-speed flow fields has become an important research object in the fields of military and national defense.

[0003] The identification of particle type parameters in high-temperature and high-speed flow fields can help provide a reference for fault diagnosis and tracing in high-altitude simulated environments. The particle parameter monitoring technology in high-temperature and high-speed flow fields mainly uses optical measurement and electrostatic induction principles for detection, which makes it difficult to identify the type effectively, accurately and quickly. Therefore, it is particularly important to explore a method based on spectral detection technology to conduct qualitative analysis of high-temperature and high-speed flow fields and abnormal particles.

[0004] Early fault diagnosis technologies, such as mechanical periodic maintenance, had many problems. Regular maintenance caused a lot of waste of manpower and financial resources, and engines often had sudden failures during use, seriously threatening human life and safety.

[0005] Therefore, during the high-speed extreme test stage of aircraft engines, there is an urgent need for effective and rapid detection and analysis methods to conduct spectral qualitative analysis of the types of particulate matter that may appear in the high-temperature and high-speed flow field, so as to provide theoretical guidance for the early fault diagnosis of aircraft engines in high-altitude simulated environments. Summary of the invention

[0006] In view of this, the present invention provides a throat area adjustment mechanism to solve the problem that in a high-temperature and high-speed flow field, due to the high flow velocity being too fast and the high-energy laser beam having a short action time, the particles fail to absorb enough energy and cannot achieve atomic transition and emit a spectrum, and the spectral information of the particles in the high-speed flow field cannot be captured, thereby failing to identify the type of the particles.

[0007] Provided is a parameter non-diffraction excitation device for a high-speed flow field spectrum, which tests particles in a high-temperature high-speed field (6) ejected by an injection portion. Under abnormal circumstances, an aircraft outlet will randomly eject particles (5) of smaller size in the high-temperature high-speed field (6). The ejected particles (5) have a size of micrometers to tens of micrometers and are low-energy-level excitation spectra. The device comprises a first laser (1), an inwardly concave non-diffraction beam expansion optical device (2), a high-energy laser (3), and a three-level non-diffraction optical device (4) which are sequentially arranged in a coaxial manner in the direction of the high-temperature high-speed field (6), wherein:

[0008] The concave non-diffraction beam expansion optical device (2) comprises an axisymmetric conical concave lens, which is coated with an optical film capable of high transmittance to the first laser (1), and the concave non-diffraction beam expansion optical device (2) is made of a high light energy material and can carry the energy of the first laser (1); the angle of the concave non-diffraction beam expansion optical device (2) corresponds to the angle of the third-level non-diffraction optical device (4);

[0009] The three-stage non-diffraction optical device (4) comprises a cross-sectional lens composed of an axisymmetric spherical surface and two-stage outer cones, the spherical surface portion is coated with an optical film capable of high transmission of the high-energy laser (3), and the curvature of the spherical surface portion forms a corresponding relationship with the included angle of the two-stage outer cone portion in the three-stage non-diffraction optical device (4), and the two-stage outer cone portion is coated with an optical film capable of high transmission of the first laser (1), and the installation included angle thereof forms a corresponding relationship with the angle in the concave non-diffraction beam expansion optical device (2) and the curvature radius of the spherical surface portion of the three-stage non-diffraction optical device (4);

[0010] The wavelength of the first laser (1) forms a corresponding relationship with the structural parameters of the high-energy laser (3), the three-level non-diffraction optical device (4) and the concave non-diffraction beam expansion optical device (2), so as to ensure that a capture interval is formed in a designated area in a high-temperature and high-speed flow field (6).

[0011] The technical beneficial effects of the present invention are:

[0012] Based on the non-diffraction preserving characteristic of non-diffraction light beams, and the principle that the potential well formed by the non-diffraction optical lens group on the laser beam can constrain particles, the particles in the high-temperature and high-speed flow field can be captured, and at the same time, the tiny particles can be confined in a specific spatial area. Under the focused excitation of a special laser, the spectrum can be excited, the spectrum of high-speed moving particles can be excited, and the type of particles in the high-temperature and high-speed flow field can be identified. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 It is a schematic diagram of the structure of a three-stage non-diffraction optical device;

[0015] Figure 2 is a schematic diagram of the structure of a concave non-diffraction beam expansion optical device;

[0016] Figure 3 It is a schematic diagram of the working principle of a three-stage non-diffraction optical device;

[0017] Figure 4 It is a schematic diagram of the structure of the present invention.

[0018] in:

[0019] R 0 , R 1 , R 2 Corresponding to the radii of the first, second and third non-diffractive optical devices, θ 2 ,θ 1 They correspond to their angles, z 1 、z 3 Corresponding to the area covered by the second and third levels, z 2 is the first-stage focal length of the three-stage non-diffraction optical device 4. DETAILED DESCRIPTION

[0020] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0021] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.

[0022] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0023] like Figure 4 The parameters of the high-speed flow field spectrum shown in the non-diffraction excitation device are tested on the particles in the high-temperature high-speed field 6 ejected by the spraying part. Under abnormal conditions, the aircraft outlet will randomly eject smaller particles 5 in the high-temperature high-speed field 6. The size of the ejected particles 5 is in the order of microns to tens of microns, and it is a low-energy level excitation spectrum, which includes a first laser 1, a concave non-diffraction beam expansion optical device 2, a high-energy laser 3 and a three-level non-diffraction optical device 4 arranged in sequence in a coaxial manner toward the direction of the high-temperature high-speed field 6, wherein:

[0024] The concave non-diffraction beam expansion optical device 2 comprises an axisymmetric conical concave lens, which is coated with an optical film capable of high transmittance to the first laser 1, and the concave non-diffraction beam expansion optical device 2 is made of a high light energy material and can carry the energy of the first laser 1; the angle of the concave non-diffraction beam expansion optical device 2 corresponds to the angle in the third-level non-diffraction optical device 4;

[0025] The three-stage non-diffraction optical device 4 includes a cross-sectional lens composed of an axisymmetric spherical surface and two-stage outer cones, the spherical surface portion is coated with an optical film capable of high transmission of the high-energy laser 3, and the curvature of the spherical surface portion corresponds to the angle between the two-stage outer cone portions in the three-stage non-diffraction optical device 4, and the two-stage outer cone portions are coated with an optical film capable of high transmission of the first laser 1, and the installation angle thereof corresponds to the angle in the concave non-diffraction beam expansion optical device 2 and the curvature radius of the spherical surface portion of the three-stage non-diffraction optical device 4;

[0026] The wavelength of the first laser 1 corresponds to the structural parameters of the high-energy laser 3, the three-stage non-diffraction optical device 4 and the concave non-diffraction beam expansion optical device 2 to ensure that a capture interval is formed in a designated area in the high-temperature and high-speed flow field 6.

[0027] It is able to spatially constrain small particles of the micron scale in high-temperature and high-speed flow fields through a controlled non-diffraction light beam and can excite them in fixed areas. In addition to its compact and simple structure, it is more important to be able to controllably constrain particles at high temperatures and high speeds, making it suitable for particle spectral excitation scenarios similar to this application.

[0028] Installation method:

[0029] The first laser 1 is installed below the concave non-diffraction beam expansion optical device 2, wherein the clamping direction of the concave non-diffraction beam expansion optical device 2 can align its plane or concave surface with the first laser 1, and the concave non-diffraction beam expansion optical device 2 is coated with an anti-reflection film capable of enhancing the first laser 1, so that as much energy of the first laser 1 as possible is projected through the device, ensuring that more laser energy forms a potential well difference for confining tiny particles;

[0030] When the concave non-diffraction beam expansion optical device 2 is at a distance d from the third-level non-diffraction optical device 4, the second and third levels of the third-level non-diffraction optical device 4 are both coated with a laser beam that can enhance the transmittance of the laser beam emitted by the first laser 1; at the same time, there is a certain correspondence between the distance d and the angle η of the concave non-diffraction beam expansion optical device 2 and R0, R1 and R2 of the third-level non-diffraction optical device 4, so as to ensure that the laser on the first laser 1 can all cover the R 0 To R 2 within the radial range;

[0031] The high-energy laser 3 is installed in the beam cavity of the first laser 1 through the concave non-diffraction beam expansion optical device 2, and a film capable of enhancing the transmittance of the high-energy laser 3 is coated on the surface of the first stage of the three-stage non-diffraction optical device 4 so that the beam energy can pass through to the maximum extent and the energy acts more on the particles constrained in the area, thereby achieving spectral excitation of the particles.

[0032] As a specific implementation method provided in this case, the wavelength of the high-energy laser 3 forms a corresponding relationship with the structural parameters of the first laser 1, the third-level non-diffraction optical device 4 and the concave non-diffraction beam expansion optical device 2 to ensure that a capture interval is formed in a designated area in a high-temperature and high-speed flow field.

[0033] As a specific implementation provided in this case, the first laser 1 emits a laser beam which passes through the concave non-diffraction beam expansion optical device 2 to form an axisymmetric circular ring laser beam, and the angle of the concave non-diffraction beam expansion optical device 2 is η;

[0034] like Figure 1As shown, the laser beam emitted by the first laser 1 passes through the concave non-diffraction beam expansion optical device 2 to form an axisymmetric ring, and then irradiates the second and third ring zones of the three-stage non-diffraction optical device 4 after an optical path d, and the corresponding angle between the two stages on the concave non-diffraction beam expansion optical device 2 is θ 1 and θ 2 The first laser 1 has a wavelength of λ and the collimated light is vertically illuminated to the third level non-diffraction optical device 4. 1 -R 2 When the radial concave non-diffraction beam expands the optical device 2 at an angle of η and is incident at an incident angle η, the corresponding relationship is as follows:

[0035] z 1 =R 1 ·[cotη 1 -tanθ 2 ];

[0036] The angle η of the concave non-diffractive beam expansion optical device 2 and the angle θ of the third-order non-diffractive optical device 4 1 ,θ 2 The angle is small and can be simplified to η 1 =(n-1)θ 2 , z max ≈R 1 cot[(n-1)θ 2 ],θ 2 >η.

[0037] As a specific implementation method provided in this case, the laser beam emitted by the first laser 1 passes through the concave non-diffraction beam expansion optical device 2 to form an axisymmetric ring, and then irradiates the second and third ring belts of the three-stage non-diffraction optical device 4 after an optical path d. The angle between the two stages on the concave non-diffraction beam expansion optical device 2 is θ. 1 and θ 2 The first laser 1 has a wavelength of λ and the collimated light is vertically illuminated by the third-level non-diffraction optical device 4, the second-level R 0 -R 1 When the angle of the concave non-diffraction beam expansion optical device 2 is η, the corresponding relationship after the incident angle η is as follows:

[0038] z 3 =R 1 ·[cotη 2 -tanθ 1 ];

[0039] Due to the angle η of the concave non-diffractive beam expansion optical device 2 and the angle θ of the third-order non-diffractive optical device 4 1 ,θ 2 The angle is small and can be simplified to η 2 =(n-1)θ1 , z max ≈R 1 cot[(n-1)θ 1 ],θ 1 >η, to ensure z 1 >z 3 Proposed θ 2 >θ 1 , where the particle constraint area is concentrated at z 3 To z 1 within the range.

[0040] like Figure 4 As shown, the high energy laser 3 emits a collimated laser beam, which passes through the first-stage plano-convex lens in the three-stage non-diffraction optical device 4 and is directed at z 3 To z 1 The focused laser beam will be focused within the z 3 To z 1 The particles within the range are excited by laser energy, and the curvature radius of the laser beam passing through the first stage of the three-stage non-diffraction optical device 4 satisfies the following relationship:

[0041]

[0042] Where R c is the radius of curvature of the first stage of the three-stage non-diffractive optical device 4.

[0043] This solves the problem that in a high-temperature and high-speed flow field, due to the high flow velocity, the high-energy laser beam has a short action time, and the particles fail to absorb enough energy to achieve atomic transition and emit spectra, and the spectral information of the particles in the high-speed flow field cannot be captured, and thus the type of particles cannot be identified. The present invention can spatially constrain small particles (micrometer level) in a high-temperature and high-speed flow field through a controlled non-diffraction beam, and can excite in a fixed point area. In addition to having the advantages of compact structure and simplicity, more importantly, it can control and constrain particles at high temperature and high speed, and is suitable for particle spectral excitation scenarios similar to this application. A three-stage non-diffraction beam generator is used. The first stage converges the high-energy excitation beam to provide excitation energy for the spectrum of the particles; the second and third stages form a potential difference through the auxiliary laser beam to achieve spatial confinement of the particles. Even if the particles are running at high speed, the non-diffraction cavity formed by the laser beam can capture the particles, and at the same time constrain the particles within a certain period of time, so that the excitation laser beam has sufficient time to act on the particles, thereby being able to excite the spectrum of the particles, achieving spectral excitation of high-speed moving particles, and solving the problem of particle type identification in high-temperature and high-speed flow fields. The present invention can spatially constrain those small particles (micrometer level) in high-temperature and high-speed flow fields through controlled non-diffraction beams, and can excite in fixed-point areas. In addition to having the advantages of compact structure and simplicity, more importantly, it can control and constrain particles at high temperature and high speed.

[0044] The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A non-diffraction excitation device for parameters of a high-speed flow field spectrum, which tests particles in a high-temperature high-speed field (6) ejected by a flame ejection unit. Under abnormal conditions, the aircraft outlet will randomly eject smaller particles (5) in the high-temperature high-speed field (6). The ejected particles (5) have a size of micrometers to tens of micrometers and are low-energy level excitation spectra, characterized in that: The invention comprises a first laser (1), an inwardly concave non-diffraction beam expansion optical device (2), a high-energy laser (3) and a three-level non-diffraction optical device (4) which are arranged in sequence in a coaxial manner in a direction facing a high-temperature and high-speed field (6), wherein: The concave non-diffraction beam expansion optical device (2) comprises an axisymmetric conical concave lens, which is coated with an optical film capable of high transmittance to the first laser (1), and the concave non-diffraction beam expansion optical device (2) is made of a high light energy material and can carry the energy of the first laser (1); the angle of the concave non-diffraction beam expansion optical device (2) corresponds to the angle of the third-level non-diffraction optical device (4); The three-stage non-diffraction optical device (4) comprises a cross-sectional lens composed of an axisymmetric spherical surface and two-stage outer cones, the spherical surface portion is coated with an optical film capable of high transmission of the high-energy laser (3), and the curvature of the spherical surface portion forms a corresponding relationship with the included angle of the two-stage outer cone portion in the three-stage non-diffraction optical device (4), and the two-stage outer cone portion is coated with an optical film capable of high transmission of the first laser (1), and the installation included angle thereof forms a corresponding relationship with the angle in the concave non-diffraction beam expansion optical device (2) and the curvature radius of the spherical surface portion of the three-stage non-diffraction optical device (4); The wavelength of the first laser (1) forms a corresponding relationship with the structural parameters of the high-energy laser (3), the three-level non-diffraction optical device (4) and the concave non-diffraction beam expansion optical device (2), so as to ensure that a capture interval is formed in a designated area in a high-temperature and high-speed flow field (6).

2. The non-diffraction excitation device for high-speed flow field spectroscopy according to claim 1, characterized in that: The wavelength of the high energy laser (3) forms a corresponding relationship with the structural parameters of the first laser (1), the three-level non-diffraction optical device (4) and the concave non-diffraction beam expansion optical device (2), so as to ensure that a capture interval is formed in a designated area in a high temperature and high speed flow field.

3. The non-diffraction excitation device for high-speed flow field spectroscopy according to claim 2, characterized in that: A first laser (1) emits a laser beam which passes through an inwardly concave non-diffraction beam expansion optical device (2) to form an axisymmetric circular ring laser beam, and the angle of the inwardly concave non-diffraction beam expansion optical device (2) is η; The laser beam emitted by the first laser (1) passes through the concave non-diffraction beam expansion optical device (2) to form an axially symmetrical circular ring and passes through an optical path d, and then irradiates the second and third ring zones of the three-stage non-diffraction optical device (4), and the corresponding included angles of the two stages on the concave non-diffraction beam expansion optical device (2) are θ1 and θ2; when the collimated light of the first laser (1) with a wavelength of λ vertically irradiates the third stage (R1-R2) region of the three-stage non-diffraction optical device (4), after passing through the concave non-diffraction beam expansion optical device (2) at an angle of η and incident at an incident angle η, the corresponding relationship is as follows: z1=R1·[cotη1-tanθ2]; The angle η of the concave non-diffraction beam expansion optical device (2) and the angles θ1 and θ2 in the three-level non-diffraction optical device (4) are relatively small and can be simplified to η1 = (n-1) θ2, z max ≈R1cot[(n-1)θ2], θ2>η.

4. The non-diffraction excitation device for high-speed flow field spectroscopy according to claim 3, characterized in that: The laser beam emitted by the first laser (1) passes through the concave non-diffraction beam expansion optical device (2) to form an axially symmetrical circular ring and passes through an optical path d, and then irradiates the second and third ring zones of the three-stage non-diffraction optical device (4), and the corresponding included angles of the two stages on the concave non-diffraction beam expansion optical device (2) are θ1 and θ2; when the collimated light of the first laser (1) with a wavelength of λ vertically irradiates the second stage (R0-R1) region of the three-stage non-diffraction optical device (4), after passing through the concave non-diffraction beam expansion optical device (2) at an angle of η, the corresponding relationship after incident at an incident angle η is as follows: z3=R1·[cotη2-tanθ1]; Since the angle η of the concave non-diffractive beam expansion optical device (2) and the angles θ1 and θ2 in the three-stage non-diffractive optical device (4) are relatively small, it can be simplified to η2 = (n-1)θ1, z max ≈R1cot[(n-1)θ1], θ1>η, to ensure z1>z3, θ2>θ1 is proposed, where the constraint area for particles is concentrated in the range from z3 to z1.

5. The parameter non-diffraction excitation device for high-speed flow field spectroscopy according to claim 4, characterized in that: The high energy laser (3) emits a collimated laser beam, which is focused within the range of z3 to z1 after passing through the first-stage plano-convex lens of the three-stage non-diffraction optical device (4). The focused laser beam excites particles constrained within the range of z3 to z1 with laser energy. The curvature radius of the laser beam passing through the first-stage of the three-stage non-diffraction optical device (4) satisfies the following relationship: Where R c is the radius of curvature of the first stage in the three-stage non-diffractive optical device (4).

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