Low-temperature pipeline flow optical window surface defogging and defrosting device based on flow purging

Abstract

The invention discloses a low-temperature pipeline flow optical window surface defogging and defrosting device based on flow purging, and relates to the field of window flow control of low-temperature pipeline flow, and the device comprises an inlet section, a contraction section, an expansion section, a window section, a collection section and an outlet section which are communicated in sequence; the inlet section is communicated with a gas source; one surface, close to the low-temperature pipeline, of the window section is an open surface; one surface, far away from the low-temperature pipeline, of the window section is a sealing surface provided with a first observation window; the device not only can eliminate the fog and frost condensation phenomenon on the surface of the optical glass, but also can effectively overcome the corrosion problem of corrosive gas to the optical glass.

Description

Technical Field

[0001] The invention relates to the field of window flow control of low-temperature pipeline flow, and in particular to a low-temperature pipeline flow optical window surface defogger based on flow purge. Background Art

[0002] In the field of aerodynamics, many pneumatic devices need to operate at low temperatures according to design requirements. In order to observe the flow field structure of the core section inside the pneumatic equipment, an optical observation window needs to be set on the wall. However, the high temperature difference between the inside and outside of the pneumatic equipment will cause gas atomization and frost on the window surface, affecting the test results of the optical test and measurement equipment, especially for some optical tests with high cleanliness requirements. At the same time, for some pneumatic equipment with corrosive operating gases, when designing the optical observation window, the impact of corrosive gases on the performance of the optical window is also a technical problem that needs to be solved urgently.

[0003] In the prior art, the conventional method of eliminating fogging and frost on optical windows generally uses a double-layer optical window and heats or replaces the gas in the interlayer. However, this method has limited protection against corrosive gases, which can cause corrosion to optical glass. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a low-temperature pipeline flow optical window surface defrosting device based on flow purge, which can not only eliminate the condensation and frost phenomenon on the optical glass surface, but also effectively overcome the corrosion problem of corrosive gases on the optical glass.

[0005] To achieve the above-mentioned purpose of the invention, the present invention provides a defrosting device for the surface of a flow optical window of a cryogenic pipeline based on flow purge, the device comprising: an inlet section, a contraction section, an expansion section, a window section, a collection section and an outlet section connected in sequence; the inlet section is connected to an air source; a side of the window section close to the cryogenic pipeline is an open surface, and a side of the window section away from the cryogenic pipeline is a sealing surface provided with a first observation window.

[0006] The present invention utilizes an inlet section, a contraction section, an expansion section, a window section, a collection section and an outlet section that are connected in sequence to form an airflow channel, and defrost is achieved by sweeping the surface of the optical window with a flowing purge airflow, and the purge air source is a non-corrosive gas input from an external air source, which can protect the optical window and prevent the corrosive gas in the low-temperature pipeline from corroding the optical glass.

[0007] One or more technical solutions provided by the present invention have at least the following technical effects or advantages:

[0008] This device can be used for low-temperature flow display and test research, can reduce the frost phenomenon of the observation window, and improve the optical visibility of the optical window;

[0009] This device can provide protection for the optical windows of various pneumatic equipment, eliminate the pollution and erosion of the optical window glass by polluting and corrosive gases, and improve the operating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of the present invention, and do not constitute a limitation on the embodiments of the present invention;

[0011] Figure 1 It is a structural schematic diagram of a low-temperature pipeline flow optical window surface defrosting device based on flow purge;

[0012] Figure 2 A schematic diagram of a cryogenic pipeline flow optical window surface defrosting device based on flow purge is provided;

[0013] Among them, 1-window section, 2-expansion section, 3-contraction section, 4-inlet section, 5-collection section, 6-outlet section, 7-this device, 8-first observation window, 9-second observation window, 10-low-temperature pipeline. DETAILED DESCRIPTION

[0014] In order to more clearly understand the above-mentioned purpose, 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 the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0015] 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 within the scope of this description. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0016] Embodiment 1;

[0017] Please refer to Figure 1-Figure 2 , Figure 1 This is a schematic diagram of the structure of a low-temperature pipeline flow optical window surface defrosting device based on flow purge. Figure 2 The present invention provides a low-temperature pipeline flow optical window surface defogger based on flow purge, and the device comprises:

[0018] The inlet section 4, the contraction section 3, the expansion section 2, the window section 1, the collection section 5 and the outlet section 6 are connected in sequence; the inlet section is connected to the gas source; the side of the window section close to the low-temperature pipeline 10 is an open surface, and the side of the window section away from the low-temperature pipeline is a sealing surface provided with a first observation window 8.

[0019] The window section is a semi-enclosed structure, the bottom surface of the window section and the two side walls of the window section are solid walls, and the top surface of the window section is an open surface in contact with the main airflow of the cryogenic pipeline flow. The condensed fog or frost on the optical window is swept away by the high-speed airflow at the outlet of the expansion section of the window surface defogger and frost device, isolating the contact between the free flow and the optical window. The airflow direction in the window section matches the airflow direction in the cryogenic pipeline.

[0020] The window section mainly uses the high-speed airflow at the outlet of the expansion section of the window surface defogger to sweep the condensed fog or frost on the optical window and isolate the contact between the running airflow in the low-temperature pipeline and the optical window. The design length of the window section mainly refers to the size of the window glass. The length is 1-1.2 times the diameter of the window glass, the height is 0.05-0.3 times the diameter of the window, and the wall surface is a smooth plane. The design dimensions of the other sections of the device design are mainly based on the design dimensions of the window section and are designed according to relevant proportions.

[0021] Among them, the expansion section is an expansion type structure design, which is mainly used to adjust the airflow velocity reaching the window area and match the core flow field. The outlet height of the expansion section is consistent with the height of the window section, the inlet height of the expansion section is 0.1-1 times the outlet height, and the length is 2-5 times the cross-sectional height of the expansion section. The wall profile curve can be a profile curve with continuous curvature such as a bicubic curve or a quintic curve, or a nozzle profile curve can be used for design.

[0022] Among them, the contraction section of the window surface defogger device is a contraction-type structural design with a square cross-section perpendicular to the airflow. It is mainly used to accelerate the airflow and reduce the turbulence of the airflow. The inlet and outlet heights of this section must be consistent with the connected front and rear sections.

[0023] A mounting hole for mounting the device is provided on one side of the low-temperature pipe wall. The mounting hole is designed to facilitate the installation of the device. A boss is provided above the inlet of the contraction section for matching with the hole wall of the mounting hole, and a boss is also provided at the outlet section for matching with the hole wall of the mounting hole. After the device is installed in the mounting hole, the boss is used to closely match with the mounting hole, and then the device is installed by sealing.

[0024] The wall surfaces of the contraction section, the expansion section and the collection section close to the cryogenic pipe are flush with the wall surface of the cryogenic pipe where the mounting hole is located. The purpose of this design is to match the direction of the purge airflow in the device with the airflow in the cryogenic pipe, so as to avoid mutual interference between the purge airflow in the device and the airflow in the cryogenic pipe.

[0025] A second observation window 9 is installed on the other side of the low-temperature pipe wall at a position corresponding to the installation hole. The second observation window provides illumination conditions, and observation is performed through the first observation window, which facilitates acquisition of high-quality images.

[0026] The contraction section is used to accelerate the airflow entering from the inlet section. The inlet and outlet heights of this section must be consistent with the connected front and rear sections. The outlet height of the contraction section is consistent with the inlet height of the expansion section. The inlet height of the contraction section is 1-4 times the outlet height. The length of the contraction section is 2-5 times the inlet height of the contraction section. The profile curve of the wall surface can be a profile curve with continuous curvature such as a bicubic curve or a quintic curve.

[0027] The expansion section is used to adjust the air flow velocity reaching the first observation window area to match the flow field velocity in the cryogenic pipeline.

[0028] The inlet section includes a first straight section and a first corner section, one end of the first straight section is connected to the gas source, the other end of the first straight section is connected to one end of the first corner section, and the other end of the first corner section is connected to the contraction section. The inlet of the inlet section extends to the outside of the cryogenic pipeline, and the purge gas flow starts from the gas source and passes through the first straight section of the inlet section, then enters the first corner section, and then enters the contraction section. The inlet section is mainly used to uniformly introduce gas from the gas supply system, and the section perpendicular to the flow direction adopts a square section.

[0029] The height of the entrance section is consistent with the height of the contraction section entrance. The corners use arc transition. The radius of the inner surface arc is 0.2-1 times the cross-section width, the radius of the outer surface arc is 1.2-1.5 times the cross-section width, and the length of the straight part of the entrance section is 1-2 times the cross-section height.

[0030] The collecting section is used to collect the airflow injected by the device. The collecting section is located downstream of the first observation window, i.e., the optical window. The section perpendicular to the flow direction adopts a square section. It is mainly used to collect the airflow injected by the surface defrosting device to reduce the impact of the injected airflow on the main airflow of the low-temperature pipeline flow. The collecting section is a structure with square sections at both ends. Considering the airflow diffusion effect, the height of the collecting section should be higher than the height of the window section outlet, with a ratio of 1.2-2 times, and the length of the collecting section is 1.5-3 times the height of the collecting section.

[0031] The outlet section includes a second straight section and a second corner section, one end of the second corner section is connected to the collecting section, the other end of the second corner section is connected to one end of the second straight section, and the other end of the second straight section is connected to the exhaust system. It is mainly used to evenly guide the gas injected by the device, and the section perpendicular to the flow direction adopts a square section. The inlet section size of the outlet section is consistent with the outlet section size of the collecting section, and the corner adopts an arc transition. The inner surface arc radius is 0.2-0.5 times the section height, the outer surface arc radius is 1.2-1.5 times the section height, and the straight section length is 1-2 times the section height.

[0032] Among them, the outlet height of the expansion section is the same as the height of the window section, the outlet height of the contraction section is the same as the inlet height of the expansion section, and the inlet height of the collection section is higher than the outlet height of the window section.

[0033] In embodiment 2;

[0034] On the basis of the first embodiment, the second embodiment of the present invention also provides a design method for a low-temperature pipeline flow optical window surface defrosting device based on flow purge. This method can design a device with the above-mentioned effects. The window segment of the device is designed mainly to provide protection for the optical windows of various pneumatic equipment, eliminate the frost phenomenon of the observation window, and improve the optical visibility of the optical window. Therefore, the size of the entire device can be determined according to the problem to be studied. The size of the window segment can then be determined based on the relevant proportions. The geometric dimensions and parameters of other sections of the device are given. This example uses a pneumatic device with a circular optical window as a reference to carry out the design of the device. The specific implementation steps of this method are as follows:

[0035] 1) Design the device structure: The device is designed to include: an inlet section, a contraction section, an expansion section, a window section, a collection section and an outlet section which are connected in sequence; the inlet section is connected to the gas source; the side of the window section close to the cryogenic pipeline is an open surface, and the side of the window section away from the cryogenic pipeline is a sealing surface provided with a first observation window.

[0036] 2) Determine the size of the window segment: Set the optical window of the pneumatic equipment, i.e. the first observation window, to be circular, and the diameter of the optical window glass to be 100mm. Based on the design principle that the length of the window segment is 1-1.2 times the diameter of the window glass, and the height of the window segment is 0.05-0.3 times the diameter of the window, determine the length of the window segment to be 110mm and the height of the window segment to be 10mm;

[0037] 3) Determine the cross-sectional size of the expansion section based on the size of the window section: According to the principle that the height of the window section is consistent with the height of the expansion section outlet, the outlet height of the expansion section is determined to be 10 mm; according to the principle that the inlet height of the expansion section is 0.1-1 times the outlet height, the inlet height of the expansion section is determined to be 2.5 mm; based on the length being 2-5 times the outlet height of the expansion section, the length of the expansion section is determined to be 30 mm, and the surface curve of the wall is designed with a bicubic curve.

[0038] 4) Determine the size of the contraction section based on the size of the expansion section: According to the design principle that the outlet height of the contraction section is consistent with the inlet height of the expansion section, the outlet height of the contraction section is determined to be 2.5 mm; according to the design principle that the inlet height of the contraction section is 1-4 times the outlet height, the inlet height of the contraction section is determined to be 5 mm; according to the design principle that the length of the contraction section is 2-5 times the inlet height of the contraction section, the length of the contraction section is determined to be 15 mm; according to the design requirements of the contraction section wall, the profile curve of the contraction section wall is determined to be a bicubic curve;

[0039] 5) Determine the size of the inlet section based on the size of the contraction section: The inlet section is mainly used to uniformly introduce gas from the gas supply system, including the corner section and the straight section. According to the design principle that the height of the inlet section is consistent with the height of the inlet of the contraction section, the cross-sectional height of the inlet section is determined to be 5mm, and the corners are transitioned by arcs. According to the design principle that the inner surface arc radius is 0.2-1 times the cross-sectional height and the outer surface arc radius is 1.2-1.5 times the cross-sectional height, the inner surface arc radius of the corner is determined to be 2.5mm, and the outer surface arc radius is 30mm. According to the straight section length of the inlet section being 1-2 times the cross-sectional height, the straight section length of the inlet section is determined to be 7.5mm.

[0040] 6) Determine the cross-sectional dimensions of the collecting section based on the size of the window section: According to the design principle that the height of the collecting section should be 1.2-2 times higher than the height of the window section outlet, and the length of the collecting section should be 1.5-3 times the height of the collecting section, determine that the height of the collecting section is 15 mm and the length of the collecting section is 30 mm;

[0041] 7) Determine the cross-sectional dimensions of the outlet section based on the dimensions of the collecting section: Determine the height of the outlet section to be 15 mm based on the consistency between the inlet cross-sectional dimensions and the outlet cross-sectional dimensions of the collecting section; determine that the arc transition is used at the corners, the inner surface arc radius is 0.2-0.5 times the cross-sectional height, and the outer surface arc radius is 1.2-1.5 times the cross-sectional height. The inner surface arc radius of the arc transition part is determined to be 5 mm, and the outer surface arc radius is 20 mm; based on the design principle that the length of the straight section is 1-2 times the cross-sectional height, determine that the length of the straight section is 20 mm.

[0042] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0043] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A low-temperature pipeline flow optical window surface defrosting device based on flow purge, characterized in that: The device comprises: An inlet section, a contraction section, an expansion section, a window section, a collection section and an outlet section are connected in sequence; the inlet section is connected to the gas source; the side of the window section close to the low-temperature pipeline is an open surface, and the side of the window section away from the low-temperature pipeline is a sealing surface with a first observation window.

2. The low-temperature pipeline flow optical window surface defrosting device based on flow purge according to claim 1 is characterized in that: A mounting hole for mounting the device is arranged on one side wall of the low-temperature pipeline.

3. The low-temperature pipeline flow optical window surface defrosting device based on flow purge according to claim 1 is characterized in that: The wall surfaces of the contraction section, the expansion section and the collection section close to the low-temperature pipe are all flush with the wall surface of the low-temperature pipe where the installation hole is located.

4. The low-temperature pipeline flow optical window surface defrosting device based on flow purge according to claim 2 is characterized in that: A second observation window is installed on the pipe wall on the other side of the low-temperature pipe at a position corresponding to the installation hole.

5. The low-temperature pipeline flow optical window surface defrosting device based on flow purge according to claim 1 is characterized in that: The contraction section is used to accelerate the airflow entering from the inlet section.

6. The low-temperature pipeline flow optical window surface defrosting device based on flow purge according to claim 1 is characterized in that: The expansion section is used to adjust the air flow velocity reaching the first observation window area to match the flow field velocity in the cryogenic pipeline.

7. The low-temperature pipeline flow optical window surface defrosting device based on flow purge according to claim 1 is characterized in that: The inlet section includes a first straight section and a first corner section, one end of the first straight section is connected to the gas source, the other end of the first straight section is connected to one end of the first corner section, and the other end of the first corner section is connected to the contraction section.

8. The low-temperature pipeline flow optical window surface defrosting device based on flow purge according to claim 1 is characterized in that: The collecting section is used to collect the airflow injected by the device.

9. The low-temperature pipeline flow optical window surface defrosting device based on flow purge according to claim 1 is characterized in that: The outlet section includes a second straight section and a second corner section, one end of the second corner section is connected to the collecting section, the other end of the second corner section is connected to one end of the second straight section, and the other end of the second straight section is connected to the exhaust system.

10. The low-temperature pipeline flow optical window surface defrosting device based on flow purge according to claim 1, characterized in that: The outlet height of the expansion section is the same as the height of the window section, the outlet height of the contraction section is the same as the inlet height of the expansion section, and the inlet height of the collection section is higher than the outlet height of the window section.

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