Liquid bridge optical observation system and method for observing internal temperature field of fluid by using same

Abstract

The invention provides a liquid bridge optical observation system and a method for observing an internal temperature field of fluid by using the same. The observation system comprises a liquid bridge model, an optical module and an acquisition module, the liquid bridge model is a fluid model and is filled with a liquid experiment working medium; the optical module is arranged on the side of the fluid model in a matched mode and comprises a laser, a first reflective mirror, a second reflective mirror, a first semi-transparent and semi-reflective mirror and a second semi-transparent and semi-reflective mirror. And the acquisition module is arranged on an output light path of the second semi-transparent and semi-reflective mirror in a matched manner and is used for recording a light beam output by the second semi-transparent and semi-reflective mirror. Based on quantitative observation of the internal temperature field of the liquid bridge model, quantitative observation of the internal temperature field of the fluid can be effectively realized through optical non-contact measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of microgravity fluid mechanics, and in particular to a liquid bridge optical observation system and a method for observing the internal temperature field of a fluid using the same. Background Art

[0002] Liquid bridge is an important physical model of microgravity fluid mechanics. It has very important research significance in high-quality crystal growth-floating zone method, AFM probe, additive manufacturing, etc. It is also a typical fluid physical model for studying buoyancy-thermal capillary convection. The temperature field of the fluid is a particularly important physical quantity in flow field research. The existing observation methods are thermocouples and infrared thermal imagers as two typical means. Among them, thermocouples are contact single-point measurements, which will affect the flow field when they penetrate into the liquid. In addition, thermocouples are single-point measurements and cannot obtain temperature changes in the entire field at the same time. Infrared thermal imagers can achieve non-contact measurement, but can only observe the temperature field of the free surface, and will be affected by the environment, resulting in large errors in the measurement of this small flow model. Because the flow itself has a very complex vortex cell structure, it is an important physical quantity in fluid research. Traditional optical testing methods such as shadow methods cannot achieve quantitative observation of flow fields.

[0003] To sum up, it is necessary to make further innovations on existing technologies. Summary of the invention

[0004] In response to the technical problems existing in the above-mentioned background technology, the present invention proposes a liquid bridge optical observation system and a method for observing the internal temperature field of a fluid using the same. The system has a reasonable concept, is based on the quantitative observation of the internal temperature field of a liquid bridge model, and achieves quantitative observation of the internal temperature field of the fluid through optical non-contact measurement. The system can be extended to more fluid models without changing the optical path.

[0005] In order to solve the above technical problems, the present invention provides a liquid bridge optical observation system, characterized in that: the observation system comprises a liquid bridge model, an optical module and a collection module;

[0006] The liquid bridge model is a fluid model and is filled with liquid experimental fluid;

[0007] The optical module is matched and arranged beside the fluid model, and comprises a laser, a first reflector, a second reflector, a first semi-transparent and semi-reflective mirror, and a second semi-transparent and semi-reflective mirror;

[0008] The laser is used to provide a visible light source, which outputs the laser through an optical fiber; the first semi-transparent and semi-reflective mirror is matched and arranged on the laser output side of the optical fiber, and is used to receive the laser light beam output by the optical fiber and split it into two light beams; the first reflector and the second reflector are respectively matched and arranged on the light paths of the two light beams separated by the first semi-transparent and semi-reflective mirror; the first reflector and the second reflector respectively receive the two light beams separated by the first semi-transparent and semi-reflective mirror and reflect them; the fluid model is matched and arranged on the light path of the reflected light of the first reflector, and the reflected light output by the first reflector is output after passing through the fluid model; the second semi-transparent and semi-reflective mirror is matched and arranged at the intersection of the reflected light beam of the first reflector and the reflected light beam of the first reflector passing through the fluid model; the second semi-transparent and semi-reflective mirror converges the reflected light beam of the first reflector and the reflected light beam of the first reflector passing through the fluid model, and then merges and outputs them;

[0009] The acquisition module is matched and arranged on the output light path of the second semi-transparent and semi-reflective mirror, and is used for recording the light beam output by the second semi-transparent and semi-reflective mirror.

[0010] The liquid bridge optical observation system, wherein: the fluid model includes a vertically arranged slide rail and an upper bridge column and a lower bridge column arranged on the slide rail and coaxially arranged in an upper and lower direction; the circumferential side wall of the upper bridge column is wrapped with an electric heating film for heating; the circumferential side wall of the lower bridge column is attached with a cooling plate for heat dissipation; the cooling plate is used to maintain the temperature of the lower bridge column; the gap formed between the bottom surface of the upper bridge column and the top surface of the lower bridge column is filled with liquid experimental fluid; the reflected light of the first reflector passes through the upper bridge column, the liquid experimental fluid and the lower bridge column and then shines on the second semi-transparent and semi-reflective mirror.

[0011] The liquid bridge optical observation system, wherein: the fluid model also includes an upper bridge fixed block and a lower bridge fixed block; the upper bridge fixed block is horizontally slidably installed on the slide rail, and the upper bridge column is matched and embedded in the center of the upper bridge fixed block; the lower bridge fixed block is also horizontally slidably installed on the slide rail and is located below the upper bridge fixed block, and the lower bridge column is matched and embedded in the center of the lower bridge fixed block.

[0012] The liquid bridge optical observation system, wherein: the periphery of the electric heating film is coated with an electric heating film outer coating film.

[0013] The liquid bridge optical observation system, wherein: the periphery of the cooling plate is coated with a cooling plate outer coating film.

[0014] The liquid bridge optical observation system, wherein: the upper bridge column and the lower bridge column are both made of optical grade sapphire.

[0015] The liquid bridge optical observation system, wherein: the first semi-transparent and semi-reflective mirror is used to split the received laser beam output by the optical fiber into two beams with an angle of 90 degrees to each other.

[0016] The liquid bridge optical observation system, wherein: the acquisition module adopts a camera.

[0017] A method for observing the internal temperature field of a fluid using a liquid bridge optical observation system mainly comprises the following steps:

[0018] 1) Apply different temperatures to the upper and lower bridge columns of the liquid bridge model, so that the liquid experimental medium inside the liquid bridge model can convect under the action of surface tension to establish an internal temperature field;

[0019] 2) Turn on the laser, the laser is emitted through the optical fiber, and is divided into two beams of light at 90° to each other by the first semi-transparent and semi-reflective mirror. The vertical reference light separated from the first semi-transparent and semi-reflective mirror is reflected by the second reflector and becomes the horizontal reference light. The observation object light separated from the first semi-transparent and semi-reflective mirror is reflected by the first reflector and becomes the vertical object light. The horizontal reference light is shone on the second semi-transparent and semi-reflective mirror, and the vertical object light is sequentially transmitted through the upper bridge column, the liquid experimental medium and the lower bridge column and then shone on the second semi-transparent and semi-reflective mirror. The horizontal reference light and the vertical object light converge on the second semi-transparent and semi-reflective mirror and are combined by the second semi-transparent and semi-reflective mirror to output interference light. The interference light is then recorded in real time by the acquisition module.

[0020] 3) According to the results recorded by the acquisition module, calculate the object-light phase change of the liquid bridge model before and after heating Then calculate the temperature field T of the liquid bridge model according to the change of refractive index with temperature dn / dT:

[0021]

[0022] Wherein, h is the liquid bridge height, and λ is the laser wavelength;

[0023] Finally, the quantitative observation of the temperature field inside the fluid is completed.

[0024] By adopting the above technical solution, the present invention has the following beneficial effects:

[0025] The liquid bridge optical observation system of the present invention has a simple and reasonable structural design. By establishing an optical observation system for a ground liquid bridge, the liquid bridge is designed to be a structure that is transparent to lasers. The beam splitting property of the laser is utilized to calculate the phase difference of the beam splitting optical path. Based on inversion, the quantitative measurement of the three-dimensional temperature field inside the liquid bridge is completed.

[0026] The method of using a liquid bridge optical observation system to observe the internal temperature field of a fluid is reasonably conceived. The proposed quantitative observation of the internal temperature field based on a liquid bridge can realize the observation of a transparent flow field through optical non-contact measurement. It can be extended to more fluid models without changing the optical path, and quantitative observation of the internal temperature field of the fluid can be realized through flow field observation.

[0027] The method of observing the internal temperature field of a fluid by using a liquid bridge optical observation system in the present invention is a quantitative observation method, which can provide design principles and technical support for portable quantitative temperature field observation equipment in the later stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a structural schematic diagram of the liquid bridge optical observation system of the present invention;

[0030] Figure 2 It is a structural schematic diagram of a liquid bridge model involved in the method of observing the internal temperature field of a fluid using a liquid bridge optical observation system according to the present invention;

[0031] Figure 3 A result diagram of the liquid bridge thermocapillary convection temperature field involved in the method of using the liquid bridge optical observation system to observe the internal temperature field of the fluid in the present invention;

[0032] Figure 4 This is a diagram of quantitative observation results of the liquid bridge model involved in the method of observing the internal temperature field of a fluid using a liquid bridge optical observation system according to the present invention.

[0033] Figure 1-2 The labels in:

[0034] E01-laser; E02-optical fiber; E03-reflector; E04-fluid model; E05-semi-transparent and semi-reflective mirror; E06-reflector; E07-semi-transparent and semi-reflective mirror; E08-camera;

[0035] S01—vertical reference light; S02—horizontal reference light; S03—observation light; S04—vertical object light; S05—interference light;

[0036] P01—upper bridge column; P02—lower bridge column; P03—electric heating film; P04—refrigeration plate; P05—upper bridge fixing block; P06—electric heating film outer covering film; P07—refrigeration plate outer covering film; P08—lower bridge fixing block; P09—slide rail. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The present invention is further explained below in conjunction with specific implementation modes.

[0039] like Figure 1 As shown, a liquid bridge optical observation system provided in this embodiment includes a liquid bridge model, an optical module and a collection module.

[0040] The liquid bridge model is a fluid model E04, which can be applied to other transparent fluid physical models, including an upper bridge column P01, a lower bridge column P02, an upper bridge fixing block P05, a lower bridge fixing block P08 and a slide rail P09; the upper bridge fixing block P05 is horizontally slidably installed on the vertically placed slide rail P09, and the upper bridge column P01 is matched and embedded in the center of the upper bridge fixing block P05; the lower bridge fixing block P08 is horizontally slidably installed on the vertically placed slide rail P09 and is located on the upper bridge fixing block Below P05, the lower bridge column P02 is matched and embedded in the center of the lower bridge fixing block P08; the upper bridge column P01 and the lower bridge column P02 are both optical grade sapphire; the circumferential outer wall of the upper bridge column P01 is wrapped with an electric heating film P03 for heating; the outer periphery of the electric heating film P03 is coated with an electric heating film outer coating film P06; the circumferential outer wall of the lower bridge column P02 is attached with a cooling plate P04 for heat dissipation, and the cooling plate P04 is used to maintain the temperature of the lower bridge column P02 and the outer periphery is coated with a cooling plate outer coating film P07. The upper bridge column P01 and the lower bridge column P02 are coaxially arranged, and the upper bridge column P01 and the lower bridge column P02 are pulled apart by a certain distance. The gap formed between the bottom surface of the upper bridge column P01 and the top surface of the lower bridge column P02 is filled with liquid experimental working fluid. Under the action of surface tension, this section of liquid is confined between the upper bridge column P01 and the lower bridge column P02, and the liquid bridge model can be established.

[0041] The optical module includes a laser E01, an optical fiber E02, a first reflector E03, a second reflector E06, a first semi-transparent mirror E05 and a second semi-transparent mirror E07. The laser E01 is used to provide a light source and can be visible light; the optical fiber E02 is connected to the light output end of the laser E01 and is used to output the laser light emitted by the laser E01; the first semi-transparent mirror E05 is located at the light beam output side of the optical fiber E02 and is used to receive the laser beam emitted by the optical fiber E02 and split it into two beams of light at 90 degrees to each other; the first reflector E03 is matched and arranged on the optical path of the observation object light S03 split by the first semi-transparent mirror E05, and the second reflector E06 is matched and arranged on the optical path of the vertical reference light S01 split by the first semi-transparent mirror E05. The first reflector E03 receives the observation object light S03 separated by the first semi-transparent mirror E05 and then reflects and outputs it. The second reflector E06 receives the vertical reference light S01 separated by the first semi-transparent mirror E05 and then reflects and outputs it. The fluid model E04 is matched and arranged on the reflected light path of the first reflector E03. The reflected light output by the first reflector E03 passes through the upper bridge column P01, the liquid experimental medium and the lower bridge column P02 of the fluid model E04 from top to bottom and then shines on the second semi-transparent mirror E07. The second semi-transparent mirror E07 is matched and arranged at the intersection of the reflected light beam of the second reflector E06, i.e., the horizontal reference light S02, and the reflected light beam of the first reflector E03 passing through the fluid model E04, i.e., the vertical object light S04. It converges the horizontal reference light S02 and the vertical object light S04 and then merges them to output as interference light S05.

[0042] The acquisition module is matched and arranged on the optical path of the interference light S05 output by the second semi-transparent and semi-reflective mirror E07. It adopts a high-speed camera E08 and is used to record the changes of the interference light S05 output by the second semi-transparent and semi-reflective mirror E07.

[0043] The method of the present invention for observing the internal temperature field of a fluid using a liquid bridge optical observation system is implemented based on the liquid bridge optical observation system of the present invention, and is specifically an optical quantitative testing method based on the above-mentioned liquid bridge model.

[0044] The method for visualizing the internal temperature field of liquid bridge buoyancy-thermal capillary convection according to the present invention mainly comprises the following steps:

[0045] S100, such as Figure 2 As shown, different temperatures are applied to the upper bridge column P01 and the lower bridge column P02 of the liquid bridge model, and the liquid experimental medium inside the liquid bridge model can convect under the action of surface tension to establish an internal temperature field;

[0046] S200, such as Figure 1As shown, the laser E01 is turned on, and the laser is emitted through the optical fiber E02, and is divided into two beams of light at 90° to each other by the first semi-transparent and semi-reflective mirror E05. The vertical reference light S01 separated from the first semi-transparent and semi-reflective mirror E05 is reflected by the second reflector E06 to become the horizontal reference light S02, and the observation object light S03 separated from the first semi-transparent and semi-reflective mirror E05 is reflected by the first reflector E03 to become the vertical object light S04; the horizontal reference light S02 output by the second reflector E06 is shone toward the second semi-transparent and semi-reflective mirror E07, and the vertical object light S04 output by the first reflector E03 is also shone toward the second semi-transparent and semi-reflective mirror E07 after passing through the upper bridge column P01, the liquid experimental medium and the lower bridge column P02 of the fluid model E04 from top to bottom. The horizontal reference light S02 and the vertical object light S04 converge together on the second semi-transparent and semi-reflective mirror E07 and are finally merged into the interference light (S05) for output. During this process, the interference light S05 can be recorded in real time by the high-speed camera E08. The original image is shown in Figure 3 .

[0047] S300, based on the results recorded by camera E08, calculate the object-light phase change before and after the liquid bridge is heated up Then calculate the liquid bridge temperature field T according to the change of refractive index with temperature dn / dT:

[0048]

[0049] In the above formula, h is the liquid bridge height, λ is the laser wavelength

[0050] The quantitative observation of the temperature field can be completed. Figure 4 .

[0051] The present invention has a reasonable conception and proposes a quantitative observation of the internal temperature field based on a liquid bridge, which can realize the observation of the transparent flow field through optical non-contact measurement. It can be extended to more fluid models without changing the optical path. In the later stage, it can provide design principles and technical support for portable quantitative temperature field observation equipment, which is suitable for promotion and application.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid bridge optical observation system, characterized in that: The observation system includes a liquid bridge model, an optical module and a collection module; The liquid bridge model is a fluid model (E04) and is filled with liquid experimental fluid; The optical module is matched and arranged beside the fluid model (E04), and comprises a laser (E01), a first reflector (E03), a second reflector (E06), a first semi-transparent mirror (E05) and a second semi-transparent mirror (E07); The laser (E01) is used to provide a visible light source, which outputs laser light through an optical fiber (E02); the first semi-transparent and semi-reflective mirror (E05) is matched and arranged on the laser output side of the optical fiber (E02), and is used to receive the laser light beam output by the optical fiber (E02) and split it into two light beams; the first reflector (E03) and the second reflector (E06) are respectively matched and arranged on the light paths of the two light beams split by the first semi-transparent and semi-reflective mirror (E05); the first reflector (E03) and the second reflector (E06) respectively receive the two light beams split by the first semi-transparent and semi-reflective mirror (E05) and reflect them; the fluid model (E04) is matched and arranged on the reflected light path of the first reflector (E03), and the reflected light output by the first reflector (E03) is output after passing through the fluid model (E04); the second semi-transparent and semi-reflective mirror (E07) is matched and arranged at the intersection of the reflected light beam of the first reflector (E03) and the reflected light beam of the first reflector (E03) passing through the fluid model (E04); the second semi-transparent and semi-reflective mirror (E07) converges the reflected light beam of the first reflector (E03) and the reflected light beam of the first reflector (E03) passing through the fluid model (E04), and then merges and outputs them; The acquisition module is matched and arranged on the output light path of the second semi-transparent and semi-reflective mirror (E07), and is used to record the light beam output by the second semi-transparent and semi-reflective mirror (E07).

2. The liquid bridge optical observation system according to claim 1, characterized in that: The fluid model (E04) comprises a vertically arranged slide rail (P09) and an upper bridge column (P01) and a lower bridge column (P02) which are arranged on the slide rail (P09) and are coaxially arranged up and down; The circumferential side wall of the upper bridge column (P01) is wrapped with an electric heating film (P03) for heating; A cooling fin (P04) for heat dissipation is attached to the circumferential side wall of the lower bridge column (P02); the cooling fin (P04) is used to maintain the temperature of the lower bridge column (P02); A liquid experimental medium is filled into the gap formed between the bottom surface of the upper bridge column (P01) and the top surface of the lower bridge column (P02); The reflected light of the first reflective mirror (E03) passes through the upper bridge column (P01), the liquid experimental medium and the lower bridge column (P02) and then shines toward the second semi-transparent and semi-reflective mirror (E07).

3. The liquid bridge optical observation system according to claim 2, characterized in that: The fluid model (E04) further includes an upper bridge fixing block (P05) and a lower bridge fixing block (P08); The upper bridge fixing block (P05) is horizontally slidably installed on the slide rail (P09), and the upper bridge column (P01) is matched and embedded in the center of the upper bridge fixing block (P05); The lower bridge fixing block (P08) is also horizontally slidably installed on the slide rail (P09) and is located below the upper bridge fixing block (P05), and the lower bridge column (P02) is matched and embedded in the center of the lower bridge fixing block (P08).

4. The liquid bridge optical observation system according to claim 2, characterized in that: The outer periphery of the electric heating film (P03) is coated with an electric heating film outer coating film (P06).

5. The liquid bridge optical observation system according to claim 2, characterized in that: The outer periphery of the refrigeration plate (P04) is coated with a refrigeration plate outer coating film (P07).

6. The liquid bridge optical observation system according to claim 2, characterized in that: The upper bridge column (P01) and the lower bridge column (P02) are both made of optical grade sapphire.

7. The liquid bridge optical observation system according to claim 1, characterized in that: The first semi-transparent and semi-reflective mirror (E05) is used to split the laser beam output by the optical fiber (E02) into two beams with an angle of 90° to each other.

8. The liquid bridge optical observation system according to claim 1, characterized in that: The acquisition module adopts a camera (E08).

9. A method for observing the internal temperature field of a fluid using the liquid bridge optical observation system according to any one of claims 1 to 8, characterized in that: The main steps include: 1) Apply different temperatures to the upper bridge column (P01) and the lower bridge column (P02) of the liquid bridge model. The liquid experimental medium inside the liquid bridge model can convect under the action of surface tension to establish an internal temperature field; 2) Turn on the laser (E01), the laser is emitted through the optical fiber (E02), and is divided into two beams of light at 90° to each other by the first semi-transparent and semi-reflective mirror (E05). The vertical reference light (S01) separated from the first semi-transparent and semi-reflective mirror (E05) is reflected by the second reflector (E06) and becomes the horizontal reference light (S02). The observation object light (S03) separated from the first semi-transparent and semi-reflective mirror (E05) is reflected by the first reflector (E03) and becomes the vertical object light (S03). S04); the horizontal reference light (S02) is directed to the second semi-transparent and semi-reflective mirror (E07), and the vertical object light (S04) is also directed to the second semi-transparent and semi-reflective mirror (E07) after passing through the upper bridge column (P01), the liquid experimental medium and the lower bridge column (P02) in sequence; and the horizontal reference light (S02) and the vertical object light (S04) are converged on the second semi-transparent and semi-reflective mirror (E07) and then combined into interference light (S05) for output; and the interference light (S05) is recorded in real time by the acquisition module; 3) Based on the results recorded by the acquisition module, calculate the object-light phase change of the liquid bridge model before and after heating Then calculate the temperature field T of the liquid bridge model according to the change of refractive index with temperature dn / dT: Among them, h is the liquid bridge height, λ is the laser wavelength; Finally, the quantitative observation of the temperature field inside the fluid is completed.

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