A fluorescent fiber optic probe device for three-phase flow detection

Abstract

The present invention relates to the technical field of three-phase flow detection, and provides a fluorescent fiber optic probe device for three-phase flow detection, comprising: a packaging shell; a sapphire probe disposed within the packaging shell; a connected small-diameter self-focusing lens and a large-diameter self-focusing lens located above the sapphire probe; an integrated fiber bundle structure divided into a transmitting fiber and a receiving fiber within a main cavity; a laser transmitting module connected to the transmitting fiber; a collimating lens located above the receiving fiber; a trapezoidal waveguide structure located above the collimating lens; a first optical focusing assembly and a second optical focusing assembly disposed side by side above the trapezoidal waveguide structure, with a reflective volume holographic grating disposed below the first optical focusing assembly; a first photoelectric conversion module and a second photoelectric conversion module; and a main control module. The device of the present invention can effectively avoid optical power attenuation caused by optical fiber splitting and filters, thereby ensuring optical signal transmission efficiency and detection accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of three-phase flow detection, and in particular to a fluorescent optical fiber probe device for three-phase flow detection. Background Art

[0002] Three-phase flow monitoring is a key component of industrial multiphase flow research. Fiber-optic probe technology uses refractive index differences to identify phase states. When the sensor contacts the fluid, the different refractive indices of the medium modulate the optical signal, which is then transmitted through the optical fiber to the photoelectric converter, generating a characteristic voltage signal—a high voltage for the gas phase and a low voltage for the liquid phase (oil / water). While this technology has achieved maturity in gas-liquid phase resolution, distinguishing between oil and water in the liquid phase still presents technical challenges.

[0003] Among the technologies used to distinguish between the three phases of oil, gas, and water, fiber optic sensing devices based on composite film-enhanced reflection optimize the light signal reflection characteristics by sequentially depositing chromium / silver / chromium / silicon dioxide multilayer thin films on the surface of a tapered optical fiber. This is combined with a threshold comparison method using an infrared light source to enhance the identification of light intensity differences between the oil and water phases. However, existing technologies still suffer from the following technical drawbacks:

[0004] (1) The physical mismatch between the outer diameter of the optical fiber or optical fiber bundle and the sapphire probe causes significant return light loss, which restricts the signal transmission efficiency and limits the detection accuracy.

[0005] (2) Relying on multi-fiber splitting and combined with filters to separate reflected light and fluorescence signals, the dual-band optical power is greatly attenuated due to multiple filtering processes. In particular, the signal-to-noise ratio is severely degraded in weak light detection scenarios, limiting the optical signal transmission efficiency and detection accuracy of the probe. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0007] To this end, the purpose of the present invention is to provide a fluorescent fiber optic probe device for three-phase flow detection. By constructing a coaxial gradient refractive index optical path coupling system and combining it with axial pitch parameter control, efficient transmission of the emitted laser and precise focusing and collection of the reverse fluorescence signal are achieved. The innovative introduction of a reflective volume holographic grating utilizes its wavelength selectivity to directionally diffract the reflected light and deflect it to the focusing channel through the reflecting surface. The fluorescence signal enters an independent detection path through zero-order transmission, effectively avoiding the optical power attenuation caused by optical fiber splitting and filters, which is beneficial to ensuring the optical signal transmission efficiency and detection accuracy.

[0008] In order to achieve the above-mentioned purpose, the technical solution of the present invention provides a fluorescent fiber optic probe device for three-phase flow detection, comprising: a packaging shell; a sapphire probe, which is arranged in the packaging shell and extends from the packaging shell; a large-diameter self-focusing lens, which is arranged in the packaging shell and is above the sapphire probe; a small-diameter self-focusing lens, which is arranged in the packaging shell and is above the large-diameter self-focusing lens; an integrated fiber bundle structure, which is arranged in the packaging shell and has one end connected to the top of the small-diameter self-focusing lens, and the other end of the integrated fiber bundle structure extends into the main cavity of the packaging shell, and is divided into two parts in the main cavity. It comprises a transmitting optical fiber and a receiving optical fiber; a laser transmitting module connected to the transmitting optical fiber; a collimating lens arranged above the receiving optical fiber; a trapezoidal waveguide structure arranged above the collimating lens; a first optical focusing component and a second optical focusing component arranged side by side above the trapezoidal waveguide structure, wherein a reflective volume holographic grating is arranged below the first optical focusing component, corresponding to the top of the collimating lens; the first optical focusing component is connected to the first photoelectric conversion module, and the top of the second optical focusing component is connected to the second photoelectric conversion module; a main control module is respectively connected to the laser transmitting module, the first photoelectric conversion module, and the second photoelectric conversion module.

[0009] Preferably, the sapphire probe extends from a narrower end of the packaging shell.

[0010] Preferably, the design parameters of the reflective volume holographic grating are determined by a reflective volume holographic grating diffraction efficiency model established based on Kogelnik coupled wave theory, and the reflective volume holographic grating diffraction efficiency model includes:

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019] ,

[0020] in, It is characterized by the angle between the incident light in the holographic medium and the normal direction z of the recording plane. Represented as raster vectors The angle with the normal direction z of the recording plane, n0 represents the average refractive index, Characterized by the wavelength of the incident light in vacuum, Characterized by the interference fringe spacing, It is characterized by the angle between the fringe plane and the object light or reference light in the holographic medium. Characterized by recording the wavelength of light in a vacuum, Characterized by the wavelength of the recording light in the holographic medium, It is characterized by the coupling coefficient of the grating, n1 is characterized by the refractive index modulation, Characterized as the incident light wave vector in the medium, Characterized by the wave number in vacuum, Characterized by the average absorption coefficient of the medium, Characterized by the absorption constant modulation amplitude, Characterized as the phase mismatch parameter, Characterized as the grating vector generated during interference recording, Characterized by the size of the grating vector generated during interference recording, Characterized as a unit vector recording the material normal direction z, Characterized as the tilt factor of the diffracted light, Characterized as the tilt factor of the incident light, is represented by the propagation constant root of the solution of the coupled differential equation of the wave, d is represented by the physical thickness of the volume grating, S(0) is represented by the amplitude of the diffracted light, It represents the diffraction efficiency and j represents the imaginary unit.

[0021] Preferably, for the dual-wavelength scenario of 470nm reflected light and 515nm fluorescent light, the refractive index modulation degree of the reflective volume holographic grating is 0.115 and the thickness is 50 μm.

[0022] Preferably, a reflective film or a reflective mirror is provided on the inclined surface of the trapezoidal waveguide structure, and the inclination angle of the inclined surface to the horizontal straight line is determined according to the diffraction angle of the reflective volume holographic grating.

[0023] Preferably, the inclination angle of the inclined surface of the trapezoidal waveguide structure is , where θ1 is the diffraction angle of the reflective volume holographic grating.

[0024] Preferably, the distance between the collimating lens and the receiving optical fiber does not exceed 3 mm; the distance between the first optical focusing component and the first photoelectric conversion module, and the distance between the second optical focusing component and the second photoelectric conversion module are both less than 15 mm.

[0025] The length between the collimating lens and the trapezoidal waveguide structure is 4.8 mm, the length between the reflective volume holographic grating and the trapezoidal waveguide structure is 6 mm, and the length between the first optical focusing assembly and the trapezoidal waveguide structure is 6 mm. The straight-line distance between the collimating lens and the reflective volume holographic grating is 10 mm.

[0026] Preferably, the first optical focusing component is a focusing lens configured with a 400-700nm AR antireflection film and has a thickness of 3mm;

[0027] The second optical focusing component is a focusing lens with a 400-700nm AR antireflection coating and a thickness of 3mm;

[0028] The collimating lens is a high refractive index lens coated with 400-700nm AR antireflection film on both sides, with a thickness of 2mm. The divergence angle for reflected light of 470nm does not exceed 3°, and the divergence angle for fluorescent light of 515nm does not exceed 2.5°.

[0029] Preferably, the diameter of the large-diameter self-focusing lens is 1 mm, and the pitch is 0.25P-0.75P;

[0030] The diameter of the small-diameter self-focusing lens is 0.5 mm, and the pitch is 0.25P.

[0031] Preferably, the integrated fiber bundle structure uses three optical fibers or seven optical fibers coupled into a bundle, the transmitting optical fiber uses a single-mode or multi-mode optical fiber with a numerical aperture of 0.13-0.22, and the receiving optical fiber uses a multi-mode optical fiber with a numerical aperture of 0.275;

[0032] The first photoelectric conversion module and the second photoelectric conversion module each include a connected PIN photodiode and an I / V conversion circuit board, and the distance between the PIN photodiode and the first optical focusing assembly or the second optical focusing assembly is 7 mm;

[0033] The laser emission module includes a laser emission control circuit board and a fiber laser emitter connected to each other.

[0034] Preferably, the fluorescent fiber optic probe device for three-phase flow detection further comprises: a tapered ferrule pressure sealing structure, which is sleeved on the packaging shell and corresponds to the position of the integrated fiber optic bundle structure to perform high-pressure sealing.

[0035] The fluorescent fiber optic probe device for three-phase flow detection proposed by the present invention has the following beneficial technical effects:

[0036] (1) The fluorescent fiber optic probe device for three-phase flow detection proposed in the present invention significantly improves the signal transmission efficiency and detection accuracy.

[0037] (2) The present invention proposes a fluorescent fiber optic probe device for three-phase flow detection, which constructs a dual self-focusing lens coupling system with compact axial dimensions. Based on the self-focusing lens characteristics of gradient refractive index materials, the pitch of the small-diameter self-focusing lens is optimized and fixed to 0.25P, and the pitch of the large-diameter self-focusing lens is adjusted to 0.25P-0.75P, preferably 0.25P, to achieve axial matching of the light field. The coupling efficiency is significantly improved, and the fluorescence receiving power and the reflected light receiving power are greatly improved, which effectively solves the problem of difficulty in matching the optical fiber bundle with the sapphire probe and provides theoretical support for miniaturized probe packaging.

[0038] (3) The present invention proposes a fluorescent fiber optic probe device for three-phase flow detection, which innovatively introduces a reflective volume holographic grating. By utilizing its wavelength selectivity, the reflected light is directionally diffracted and deflected to the focusing channel through the reflective surface. The fluorescent signal enters the independent detection path through zero-order transmission, effectively avoiding the optical power attenuation caused by optical fiber splitting and filters, which is beneficial to ensuring the optical signal transmission efficiency and detection accuracy.

[0039] (4) The present invention proposes a fluorescent fiber optic probe device for three-phase flow detection. For the dual-wavelength scenario of 470nm reflected light and 515nm fluorescence, the refractive index modulation degree of the reflective volume holographic grating is 0.115 and the thickness is 50μm. The diffraction efficiency of this reflective volume holographic grating can reach 1 when the incident wavelength is 470nm, and is only 0.0162 at a wavelength of 515nm. The reflective volume holographic grating can effectively achieve dual-wavelength spectral separation of 470nm and 515nm.

[0040] (5) The fluorescent fiber optic probe device for three-phase flow detection proposed in the present invention can effectively solve the problem of significant optical power attenuation caused by traditional filters and independent optical fiber splitting, and at the same time achieves efficient splitting of reflected light and fluorescence, while maintaining a high optical power transmission efficiency and ensuring the independence of reflected light and fluorescence detection.

[0041] (6) The fluorescent fiber optic probe device for three-phase flow detection proposed in the present invention significantly improves the signal-to-noise ratio and detection sensitivity of the dual-band signal through optical path integration and wavelength selective spatial separation. At the same time, the corresponding probe packaging structure is adopted to enhance the system reliability.

[0042] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0044] Figure 1A structural view of a fluorescent optical fiber probe device for three-phase flow detection according to an embodiment of the present invention is shown;

[0045] Figure 2 Shown Figure 1 A partial enlarged schematic diagram of the structure of the fluorescent fiber optic probe device for three-phase flow detection;

[0046] Figure 3 Shown Figure 1 Schematic diagram of the structure of the double self-focusing lens probe part of the fluorescent fiber probe device for three-phase flow detection;

[0047] Figure 4 Shown Figure 1 Schematic diagram of the connection between the integrated optical fiber bundle structure and the small-diameter self-focusing lens of the fluorescent optical fiber probe device for three-phase flow detection;

[0048] Figure 5 A schematic diagram of the simulation of the spectroscopic separation of reflected light (blue) and fluorescent light (green) by a reflective volume holographic grating is shown;

[0049] Figure 6 The figure shows the relationship between the diffraction efficiency of the reflective volume holographic grating and the wavelength;

[0050] Figure 7 shows a diagram of received power data of reflected light at different pitches of a dual self-focusing lens probe according to an embodiment of the present invention;

[0051] Figure 8 FIG2 shows a graph of the received power data of the double self-focusing lens probe for fluorescence at different pitches according to an embodiment of the present invention;

[0052] Figure 9 A comparison of the received optical power between the dual self-focusing lens probe and the direct coupling probe is shown;

[0053] Figure 10 A diagram showing a simulation overall model of a fluorescent optical fiber probe device for three-phase flow detection according to an embodiment of the present invention is shown;

[0054] Figure 11 A schematic diagram showing a situation where a first photoelectric conversion module of a fluorescent optical fiber probe device for three-phase flow detection receives light according to an embodiment of the present invention is shown;

[0055] Figure 12 FIG2 shows a schematic diagram of light received by the second photoelectric conversion module of the fluorescent optical fiber probe device for three-phase flow detection according to an embodiment of the present invention.

[0056] in, Figures 1 to 5 as well as Figure 10 The corresponding relationship between the reference numerals and components is as follows:

[0057] 102. Package shell, 104. Sapphire probe, 106. Large-diameter self-focusing lens, 108. Small-diameter self-focusing lens, 110. Integrated fiber bundle structure, 1102. Transmitting optical fiber, 1104. Receiving optical fiber, 112. Laser emission module, 1122. Laser emission control circuit board, 1124. Fiber laser transmitter, 114. Collimating lens, 116. Trapezoidal waveguide structure, 118. First optical focusing component, 120. Second optical focusing component, 122. Reflective volume holographic grating, 124. First photoelectric conversion module, 126. Second photoelectric conversion module, 128. Main control module, 130. PIN photodiode, 132. I / V conversion circuit board, 134. Conical ferrule pressure sealing structure, 202. Water tank. DETAILED DESCRIPTION

[0058] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0059] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0060] The following combination Figures 1 to 12 A fluorescent optical fiber probe device for three-phase flow detection according to an embodiment of the present invention is described in detail.

[0061] like Figures 1 to 4As shown, a fluorescent fiber optic probe device for three-phase flow detection according to an embodiment of the present invention includes: a packaging shell 102, a sapphire probe 104, a large-diameter self-focusing lens 106, a small-diameter self-focusing lens 108, an integrated fiber bundle structure 110, a laser emitting module 112, a collimating lens 114, a trapezoidal waveguide structure 116, a first optical focusing assembly 118, a second optical focusing assembly 120, a first photoelectric conversion module 124, a second photoelectric conversion module 126, a main control module 128, etc. The sapphire probe 104 is disposed within the packaging shell 102 and extends from the narrow end of the packaging shell 102 to achieve direct contact with the three-phase fluid medium. The large-diameter self-focusing lens 106 is disposed in the package shell 102 and is located above the sapphire probe 104. The small-diameter self-focusing lens 108 is disposed in the package shell 102 and is located above the large-diameter self-focusing lens 106. The two form a dual-self-focusing lens coupling system with compact axial dimensions and high coupling efficiency, which can effectively solve the problem of difficult diameter matching between the optical fiber bundle and the sapphire probe 104. The integrated optical fiber bundle structure 110 is disposed in the package shell 102 and one end is connected to the top of the small-diameter self-focusing lens 108, as shown in FIG. Figure 3 and Figure 4As shown. The other end of the integrated fiber bundle structure 110 extends into the main cavity of the packaging shell 102, and is divided into a transmitting fiber 1102 and a receiving fiber 1104 in the main cavity. The integrated fiber bundle structure 110 uses three optical fibers or seven optical fibers coupled into a bundle. The transmitting optical fiber 1102 uses a single-mode or multi-mode optical fiber with a numerical aperture of 0.13-0.22, which can adapt to the transmission of excitation light. The receiving optical fiber 1104 uses a multi-mode optical fiber with a numerical aperture of 0.275, which can realize the collection of reflected light and fluorescence. The laser emission module 112 includes a laser emission control circuit board 1122 and a fiber laser emitter 1124, which are used to generate and output laser. The collimating lens 114 is arranged above the receiving optical fiber 1104, which can realize the collimation and shaping of the reflected light and fluorescence. The trapezoidal waveguide structure 116 is arranged above the collimating lens 114, and is used to transmit the collimated fluorescence and reflected light, so as to realize the redirection of the reflected light path to linear propagation. A first optical focusing assembly 118 and a second optical focusing assembly 120 are arranged side by side above the trapezoidal waveguide structure 116. A reflective volume holographic grating 122 is positioned below the first optical focusing assembly 118, corresponding to the position above the collimating lens 114. The first optical focusing assembly 118 is connected to a first photoelectric conversion module 124, while the second optical focusing assembly 120 is connected above the second photoelectric conversion module 126. The first optical focusing assembly 118 focuses the fluorescence light on the first photoelectric conversion module 124, while the second optical focusing assembly 120 focuses the reflected light on the second photoelectric conversion module 126. A main control module 128 is connected to the laser emission module 112, the first photoelectric conversion module 124, and the second photoelectric conversion module 126, respectively. Thus, by constructing a coaxial graded-index optical coupling system, efficient transmission of the emitted laser light and precise focused collection of the reverse fluorescence signal are achieved. The innovative introduction of the reflective volume holographic grating 122 effectively avoids optical power attenuation caused by fiber optic splitting and filters, thereby ensuring optical signal transmission efficiency and detection accuracy.

[0062] Furthermore, the design parameters of the reflective volume holographic grating 122 are determined by a reflective volume holographic grating diffraction efficiency model established based on Kogelnik coupled wave theory. The reflective volume holographic grating diffraction efficiency model includes:

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] ,

[0072] in, It is characterized by the angle between the incident light in the holographic medium and the normal direction z of the recording plane. Represented as raster vectors The angle with the normal direction z of the recording plane, n0 represents the average refractive index, Characterized by the wavelength of the incident light in vacuum, Characterized by the interference fringe spacing, It is characterized by the angle between the fringe plane and the object light or reference light in the holographic medium. Characterized by recording the wavelength of light in a vacuum, Characterized by the wavelength of the recording light in the holographic medium, It is characterized by the coupling coefficient of the grating, n1 is characterized by the refractive index modulation, Characterized as the incident light wave vector in the medium, Characterized by the wave number in vacuum, Characterized by the average absorption coefficient of the medium, Characterized by the absorption constant modulation amplitude, Characterized as the phase mismatch parameter, Characterized as the grating vector generated during interference recording, Characterized by the size of the grating vector generated during interference recording, Characterized as a unit vector recording the material normal direction z, Characterized as the tilt factor of the diffracted light, Characterized as the tilt factor of the incident light, is represented by the propagation constant root of the solution of the coupled differential equation of the wave, d is represented by the physical thickness of the volume grating, S(0) is represented by the amplitude of the diffracted light, It represents the diffraction efficiency and j represents the imaginary unit.

[0073] For the dual-wavelength scenario of 470nm excitation light and 515nm fluorescence, a reflective volume holographic grating structure with a refractive index modulation degree of 0.115 and a thickness of 50μm is optimized and designed.

[0074] Specifically, the two recording beams are 0° and 225° to the normal direction z of the recording material respectively. It is half of the angle between the two recording beams, that is, 67.5°. According to the geometric relationship, we can get is 22.5°, the wavelength λ0 of the recording light in vacuum is 0.47 μm, the refractive index modulation degree n1 is 0.115, the average refractive index n0 is 1.57, the average absorption coefficient α of the medium and the absorption constant modulation amplitude α1 are both set to 0, and the grating thickness d is 50 μm.

[0075] This determines the grating vector generated during interference recording and its vector size , characterizing the spatial periodic structure of the interferometric recording.

[0076] For the recording wavelength λ0, the Bragg optimal incident angle is determined by the wave vector phase matching condition, that is, when the angle between the incident light and the normal direction z of the recording plane is Calculate the wavelength range point by point, and calculate the incident light wave vector in the medium at each specific incident wavelength λ. and its wave number in vacuum , phase mismatch parameters , and the tilt factor of the diffracted light , the tilt factor of the incident light According to the refractive index modulation n1 and the wave number in vacuum , calculate the coupling coefficient of the grating , and establish the coupled wave equations for the propagation of light waves in the volume grating at each different incident wavelength λ, and solve the numerical solution of the equations According to the numerical solution and the physical thickness d of the volume grating, solve the amplitude S(0) of the diffracted light, and finally calculate the diffraction efficiency of the volume grating at each wavelength λ , the results are as follows Figure 6 This section is implemented using Python programming. When using reflective volume holographic grating structures with different refractive index modulation and thickness, the corresponding parameter settings are substituted to plot the corresponding diffraction efficiency vs. wavelength graph, thereby determining the design parameters of the reflective volume holographic grating.

[0077] like Figure 5 and Figure 6 As can be seen, the diffraction efficiency of a reflective volume holographic grating structure with a refractive index modulation of 0.115 and a thickness of 50 μm reaches 1 at an incident wavelength of 470 nm, but is only 0.0162 at a wavelength of 515 nm. This significant difference confirms the effectiveness of the reflective volume holographic grating 122 in dual-wavelength spectral separation at 470 nm and 515 nm.

[0078] Furthermore, a reflective film or a reflective mirror is provided on the inclined surface of the trapezoidal waveguide structure 116 , and the inclination angle of the inclined surface to the horizontal line is determined according to the diffraction angle of the reflective volume holographic grating 122 .

[0079] Furthermore, the inclination angle of the inclined surface of the trapezoidal waveguide structure 116 is , where θ1 is the diffraction angle of the reflective volume holographic grating 122 .

[0080] Thus, when transmitting the collimated fluorescence and reflected light, the reflected light path is turned to a straight line transmission. For example, when the diffraction angle of the reflective volume holographic grating 122 is 45°, the inclination angle of the inclined surface of the trapezoidal waveguide structure 116 is 67.5°. Figure 2 shown.

[0081] Furthermore, the distance between the collimating lens 114 and the receiving optical fiber 1104 is no more than 3 mm; the distance between the first optical focusing assembly 118 and the first photoelectric conversion module 124, and the distance between the second optical focusing assembly 120 and the second photoelectric conversion module 126 are all less than 15 mm. This further ensures that the fluorescent light and the reflected light can be accurately focused.

[0082] Furthermore, the length between the collimating lens 114 and the trapezoidal waveguide structure 116 is 4.8 mm, the length between the reflective volume holographic grating 122 and the trapezoidal waveguide structure 116 is 6 mm, and the length between the first optical focusing assembly 118 and the trapezoidal waveguide structure 116 is 6 mm. The straight-line distance between the collimating lens 114 and the reflective volume holographic grating 122 is 10 mm.

[0083] Furthermore, the first optical focusing component 118 is a focusing lens configured with a 400-700nm AR anti-reflection film and has a thickness of 3mm; the second optical focusing component 120 is a focusing lens configured with a 400-700nm AR anti-reflection film and has a thickness of 3mm; the collimating lens 114 is a high-refractive-index lens coated with a 400-700nm AR anti-reflection film on both sides and has a thickness of 2mm. The divergence angle for reflected light of 470nm does not exceed 3°, and the divergence angle for fluorescent light of 515nm does not exceed 2.5°.

[0084] This further ensures that the reflected light and fluorescence can be accurately focused after preliminary simple collimation and shaping.

[0085] Furthermore, the diameter of the large-diameter self-focusing lens 106 is 1 mm, and the pitch is 0.25P-0.75P; the diameter of the small-diameter self-focusing lens 108 is 0.5 mm, and the pitch is 0.25P.

[0086] The pitch matching model is established by ZEMAX optical simulation. The large diameter self-focusing lens 106 is A (1mm), and the small diameter self-focusing lens 108 is B (0.5mm). The received power of the double self-focusing lens probe for reflected light at different pitches is as follows: Figure 7 The received power of the double self-focusing lens probe for fluorescence at different pitches is shown in Figure 8 As shown. Figure 7 and Figure 8 It can be seen that when the pitch of A is fixed and the pitch of B is changed, the reflected light and fluorescence results show a periodic pattern. At the same time, when the pitch of the autofocus lens changes, the longer the lens length, the greater the loss.

[0087] The pitch matching model was established through ZEMAX optical simulation. The pitch of the small diameter lens was optimized and fixed to 0.25P. At the same time, the large diameter lens was adjusted in the pitch range of 0.25P to 0.75P to achieve axial matching of the light field. The optical power of the fluorescence and reflected light was set to P0, and simulation calculations were performed. The comparison of the received optical power between the dual self-focusing lens probe and the direct coupling probe is shown in the figure. Figure 9 As shown. Figure 9 As can be seen, both the fluorescence and reflected light received powers outperform the direct-coupled benchmark. In particular, with the optimized dual-lens configuration using a 0.25P pitch, the fluorescence received power reaches 0.454P0, a 1.57-fold increase over the direct-coupled 0.290P0. The reflected light power also increases from the baseline value of 0.185P0 to 0.482P0, achieving a 2.6-fold efficiency gain.

[0088] Depend on Figures 7 to 9 It can be seen that the best effect is achieved when the pitch of the dual self-focusing lenses A and B are both 0.25P. Through pitch parameterized design, the problem of difficult matching of the diameters of the optical fiber bundle and the sapphire probe 104 is effectively solved, providing theoretical support for miniaturized probe packaging.

[0089] In this application, the first photoelectric conversion module 124 and the second photoelectric conversion module 126 have the same structure. They both include a connected PIN photodiode 130 and an I / V conversion circuit board 132. The distance between the PIN photodiode 130 and the first optical focusing assembly 118 or the second optical focusing assembly 120 is 7 mm. The laser emission module 112 includes a connected laser emission control circuit board 1122 and a fiber laser emitter 1124. This further ensures the separate focusing and detection effects of fluorescence and reflected light.

[0090] Furthermore, if Figure 1 As shown, the fluorescent fiber optic probe device for three-phase flow detection also includes: a tapered ferrule pressure sealing structure 134, which is sleeved on the packaging shell 102 and corresponds to the position of the integrated fiber bundle structure 110, and can perform high-pressure sealing to establish a high-pressure sealing connection system.

[0091] The system model of the fluorescent fiber optic probe device for three-phase flow detection proposed in this invention is constructed based on the ZEMAX optical simulation platform. Its core components adopt modular design, such as Figure 10As shown, the integrated fiber bundle structure 110 includes seven 62.5 / 125μm optical fibers (numerical aperture 0.275). The top fiber is configured as a transmitting fiber 1102, serving as the excitation light transmission channel, and the remaining six fibers are configured as receiving fibers 1104, serving as light receiving channels. The optical coupling module consists of a pair of self-focusing lenses (diameters of 0.5mm and 1mm, respectively, with a pitch of 0.25P) and a sapphire probe 104 (diameter 0.8mm, end angle 90°). The volume holographic spectroscopic detection system includes three lenses coated with a 400-700nm AR coating, a reflective volume holographic grating 122 (diffraction angle 45°), and a waveguide bevel coated with a reflective coating.

[0092] During the simulation parameter setting, software limitations prevented us from simulating the entire fluorescence excitation process. The direction of the stimulated fluorescence emitted by the analyte in the solution is independent of the direction of the excitation light, resulting in a spherical radiation pattern. Therefore, we used an elliptical light source to simulate fluorescence emission, with its power, along with the excitation light source, set to 1W. It is worth noting that when analyzing the reflected signal generated by the contact between the sapphire probe 104 and the air medium, we eliminated interference from the water tank 202 model, effectively placing the probe in air. Although the trapezoidal waveguide structure was simplified to an inclined surface due to modeling limitations of the simulation software, the parameter settings and shape of the reflective film ensured the effectiveness of the simulation.

[0093] First, ZEMAX simulation software was used to simulate and calculate the total power of reflected light and fluorescence from all receiving fibers 1104. Subsequently, the probe was connected to a volume holographic spectrometer system model for simulation to quantitatively determine the parameters of the reflected light power and fluorescence power received by the detector after spectrometry. Finally, by comparing and analyzing the pre- and post-simulation data, the system evaluated the functional effectiveness of the device and its energy conversion efficiency.

[0094] The first photoelectric conversion module 124 and the second photoelectric conversion module 126 of the fluorescent optical fiber probe device for three-phase flow detection receive light, as shown in FIG. Figure 11 and Figure 12 shown.

[0095] Simulation results show that when the probe is exposed to air, the reflected light retains 82.69% of its optical power after passing through the volume holographic spectrometer. When exposed to water, the reflected light power decreases by an order of magnitude compared to the bubble environment, but still maintains a transmission efficiency of 88.17%. This result is consistent with theoretical expectations and verifies the reliability of the simulation.

[0096] Under oil-based conditions, when fluorescence is emitted from a certain distance from the probe tip and transmitted through an optical fiber (ignoring the influence of light reflected from the aqueous medium, separate simulations were performed), the volume holographic spectrometer system still maintains a fluorescence power of 71.11%. Considering that in real applications, the excitation light often differs by three orders of magnitude from the excited fluorescence, simulations were performed with the fluorescence power P1 set three orders of magnitude lower than the excitation light P0. The results show that the system still maintains a transmission efficiency of 71.09%, which is consistent with the previous results.

[0097] Further analysis shows that when excitation light P0 is transmitted through water and excites fluorescence in the oil medium, the impact of the reflected light on the fluorescence receiver differs by two orders of magnitude compared to the effect of fluorescence power P1. This result indicates that the reflected light signal transmitted by the probe in water does not significantly interfere with fluorescence detection. Similarly, the effect of the fluorescence signal on the reflected light detector is negligible, with the difference also varying by three orders of magnitude (when exposed to water). Furthermore, in the presence of bubbles, the impact of the reflected light on the fluorescence receiver differs by one order of magnitude compared to the actual fluorescence signal P1.

[0098] The simulation experiments and analysis above demonstrate that the designed device effectively resolves the significant optical power attenuation caused by traditional filters and independent optical fiber splitting, while achieving efficient splitting of reflected light and fluorescence. This device maintains high optical power transmission efficiency while ensuring the independence of reflected light and fluorescence detection.

[0099] In the present invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "plurality" refers to two or more, unless expressly limited otherwise. Terms such as "installed," "connected," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; "connected" can mean a direct connection or an indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0100] In the description of the present invention, it should be understood that the directions or positional relationships indicated by terms such as "up", "down", "left", "right", "front" and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0101] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0102] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A fluorescent fiber optic probe device for three-phase flow detection, characterized in that: include: Encapsulation shell; a sapphire probe, disposed in the packaging shell and extending from the packaging shell; A large-diameter self-focusing lens is disposed in the packaging shell and is located above the sapphire probe; a small-diameter self-focusing lens is disposed in the packaging shell and is located above the large-diameter self-focusing lens; An integrated fiber bundle structure is arranged in the packaging shell, and one end is connected to the top of the small-diameter self-focusing lens, and the other end of the integrated fiber bundle structure extends into the main cavity of the packaging shell, and is divided into a transmitting fiber and a receiving fiber in the main cavity; a laser transmitting module is connected to the transmitting fiber; a collimating lens is arranged above the receiving fiber; a trapezoidal waveguide structure is arranged above the collimating lens; a first optical focusing component and a second optical focusing component are arranged side by side above the trapezoidal waveguide structure, wherein a reflective volume holographic grating is arranged below the first optical focusing component, corresponding to the top of the collimating lens; the first optical focusing component is connected to the first photoelectric conversion module, and the top of the second optical focusing component is connected to the second photoelectric conversion module; a main control module is respectively connected to the laser transmitting module, the first photoelectric conversion module, and the second photoelectric conversion module.

2. The fluorescent optical fiber probe device for three-phase flow detection according to claim 1, characterized in that: The sapphire probe extends from a narrower end of the packaging shell.

3. The fluorescent optical fiber probe device for three-phase flow detection according to claim 1, characterized in that: A reflective film or a reflective mirror is provided on the inclined surface of the trapezoidal waveguide structure, and an inclination angle between the inclined surface and the horizontal straight line is determined according to the diffraction angle of the reflective volume holographic grating.

4. The fluorescent optical fiber probe device for three-phase flow detection according to claim 3, characterized in that: The inclination angle of the inclined surface of the trapezoidal waveguide structure is , where θ1 is the diffraction angle of the reflective volume holographic grating.

5. The fluorescent optical fiber probe device for three-phase flow detection according to claim 1, characterized in that: The distance between the collimating lens and the receiving optical fiber does not exceed 3 mm; the distance between the first optical focusing component and the first photoelectric conversion module, and the distance between the second optical focusing component and the second photoelectric conversion module are both less than 15 mm.

6. The fluorescent optical fiber probe device for three-phase flow detection according to claim 1, characterized in that: The first optical focusing component is a focusing lens with a 400-700nm AR antireflection coating and a thickness of 3mm; The second optical focusing component is a focusing lens equipped with a 400-700nm AR anti-reflection film with a thickness of 3mm; the collimating lens is a high-refractive-index lens coated with a 400-700nm AR anti-reflection film on both sides with a thickness of 2mm. The divergence angle for the reflected light of 470nm does not exceed 3°, and the divergence angle for the fluorescent light of 515nm does not exceed 2.5°.

7. The fluorescent optical fiber probe device for three-phase flow detection according to claim 1, characterized in that: The diameter of the large-diameter self-focusing lens is 1 mm, and the pitch is 0.25P-0.75P; the diameter of the small-diameter self-focusing lens is 0.5 mm, and the pitch is 0.25P.

8. The fluorescent fiber optic probe device for three-phase flow detection according to claim 1, characterized in that: The integrated fiber bundle structure uses three or seven optical fibers coupled into a bundle, the transmitting optical fiber uses a single-mode or multi-mode optical fiber with a numerical aperture of 0.13-0.22, and the receiving optical fiber uses a multi-mode optical fiber with a numerical aperture of 0.275; the first photoelectric conversion module and the second photoelectric conversion module both include a connected PIN photodiode and an I / V conversion circuit board, and the distance between the PIN photodiode and the first optical focusing component or the second optical focusing component is 7 mm; the laser emission module includes a connected laser emission control circuit board and a fiber laser emitter.

9. The fluorescent optical fiber probe device for three-phase flow detection according to claim 1, characterized in that: It also includes a tapered ferrule compression sealing structure, which is sleeved on the packaging shell and corresponds to the position of the integrated optical fiber bundle structure to perform high-pressure sealing.

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