A gas replacement structure and method for a closed optical path system

Abstract

The present invention relates to the field of high-energy laser technology, and relates to a gas replacement structure and method for a closed optical path system. The gas replacement structure includes: a closed optical path channel provided with an air inlet and an air outlet; a plurality of flow guiding structures respectively arranged at the air inlet and the air outlet; the flow guiding structure includes at least three layers of flow guiding members arranged at intervals, and a plurality of flow splitting structures are communicated between adjacent flow guiding members; an air inlet structure and an air outlet structure are respectively arranged on the foremost and the last flow guiding members and are used for communicating with the closed optical path or the air flow path. The present invention uses a flow guiding device with a multi-layered array arrangement of air holes for gas replacement, which can form a uniform air flow distribution in the closed optical path channel, reduce the gas flow rate, prevent the risk of minute dust being adsorbed onto the mirror surface due to a large air flow rate in the closed channel, control the internal turbulence of the channel, and reduce the phase distortion caused by the non-uniform distribution of gas density; increase the effective gas replacement area, shorten the replacement time, and reduce the gas consumption.

Description

Technical Field

[0001] The present invention relates to the field of high-energy laser technology, and particularly to a gas replacement structure and method for a closed optical path system. Background Art

[0002] In a high-power laser emission system, the channel thermal effect has become a key issue affecting the beam quality and restricting the operation efficiency. During the transmission of laser in the channel, internal gas molecules and particles, especially water vapor molecules, will absorb the laser energy and be heated, simultaneously generating a thermal effect and introducing aberration, resulting in the deterioration of the beam quality of the high-power laser system.

[0003] As the light guiding optical path of a high-power laser emission system, the Coudé optical path deflects the direction of the laser beam through a plane mirror, changing the beam direction. The distance that the laser travels in the Coudé optical path channel is up to several meters or even dozens of meters, which is the optical path channel where the thermal effect problem is mainly studied in the high-power laser emission system. In order to improve the thermal effect problem in the Coudé optical path channel, more reports are on injecting a flowing gas with a low absorption coefficient axially. Since the open axial gas blowing scheme is difficult to implement in engineering, it is usually necessary to inject dry nitrogen into the closed channel to control the heat accumulation in the optical path channel.

[0004] Currently, in order to control the gas flow velocity and distribution in the channel, a single inlet and outlet pipe method with a low flow rate is used for gas replacement, which has problems such as uneven gas flow distribution in the cavity, uncontrollable gas flow rate, low replacement efficiency, and large gas consumption.

[0005] Therefore, a more reasonable technical solution needs to be proposed to solve the technical problems existing in the prior art. Summary of the Invention

[0006] To at least overcome one of the above-mentioned defects, the present invention proposes a gas replacement structure and method for a closed optical path system. By using a gas diversion structure to divert and guide the gas entering the optical path, the gas flow enters the closed optical path channel more uniformly, and the entire ventilation process has a low turbulence intensity, controllable gas flow rate, short replacement time, and small gas consumption.

[0007] To achieve the above object, the gas replacement structure disclosed by the present invention can adopt the following technical solutions:

[0008] A gas replacement structure for a closed optical path system, applied to a closed optical path, comprising:

[0009] A closed optical path channel, provided with an air inlet and an air outlet;

[0010] A number of flow guiding structures are respectively arranged at the air inlet and the air outlet; the flow guiding structure includes at least three layers of continuously spaced flow guiding members, the interior of the flow guiding member is a gas cavity, and a number of flow dividing structures are communicatively arranged between adjacent flow guiding members; an air inlet structure and an air outlet structure are respectively arranged on the foremost and the last flow guiding members, and are used to connect and close the optical path or the air flow path.

[0011] The above-disclosed gas replacement structure aims to provide uniform dry gas for the closed optical path, so that the gas entering the closed optical path can avoid thermal effects in the high-energy laser environment and affect the propagation of the laser. The flow guiding structure enables the air flow to enter the closed optical path evenly, avoids turbulence through the guidance of the flow guiding structure, and can complete the gas replacement quickly and efficiently, and can improve the transmission effect of the high-energy laser closed optical path.

[0012] Further, in the present invention, as a gas guiding structure, the flow guiding member is not uniquely limited to the available solutions, and one feasible option is optimized and given here: the flow guiding member includes a flow guiding plate. When adopting such a solution, the flow guiding plate can provide a relatively wide surface structure, and the internal gas cavity makes the gas uniform, which is convenient for maintaining a stable optical path environment in the subsequent closed optical path.

[0013] Further, in the present invention, the structure of the flow guiding member is regular to facilitate eliminating turbulence in the air flow. Specifically, one feasible option is optimized and given here: the flow guiding member has a uniform thickness and the thickness is 5 mm to 50 mm, and the length and width of the flow guiding member are at least 10 times the thickness of the flow guiding member. When adopting such a solution, the control of the length and width of the flow guiding member can provide a sufficiently large gas cavity area, which is more convenient for eliminating gas turbulence.

[0014] Further, in the present invention, the air inlet structure and the air outlet structure are not uniquely limited, and a variety of feasible solutions can be adopted. One feasible option is optimized and given here: the air inlet structure and the air outlet structure include a number of flow guiding air holes, and the air inlet structure and the air outlet structure are symmetrical. When adopting such a solution, the flow guiding air holes can be evenly distributed on the end face of the outer guiding member, so that the gas entering the guiding member can be more uniform, reducing initial turbulence and becoming more stable after flowing through subsequent guiding members; it can also stably control the pressure distribution in the closed optical path channel, effectively reducing the phase distortion problem caused by non-uniform pressure distribution resulting in non-uniform gas density distribution.

[0015] Still further, the present invention continues to optimize the setting of the flow guiding air holes, and gives the following feasible option: the number of the flow guiding air holes is 1 to 10, and the aperture of the flow guiding air holes is 5 mm to 15 mm. When adopting such a solution, the more the number of the flow guiding air holes and the smaller the aperture, the smoother the air flow entering the guiding member, and the more controllable the gas flow rate and the air change time.

[0016] Further, in the present invention, the flow splitting structure is used to guide the air flow in one guide member into an adjacent guide member, making the air flow denser to eliminate turbulence and achieve a stable laminar flow state. Here, the flow splitting structure is optimized and a feasible option is given as follows: the flow splitting structure includes a number of flow splitting air pipes distributed in an array, and the diameter of the flow splitting air pipe is smaller than the aperture diameter of the diversion air holes. When adopting such a scheme, the flow splitting air pipes are evenly distributed between two adjacent guide members.

[0017] Further, the diameter of the flow splitting air pipes adopted in the present invention is within a suitable range. Specifically, the diameter of the flow splitting air pipes is 1 mm to 10 mm.

[0018] Further, in order to improve the effect of gas guiding and splitting, the arrangement of the flow splitting structure is improved. Here, a feasible option is given as follows: the number of flow splitting air pipes arranged between adjacent guide members close to the air inlet structure is greater than or equal to the number of flow splitting air pipes arranged between adjacent guide members close to the air outlet structure.

[0019] Furthermore, here the flow splitting structure is further optimized and a feasible option is given as follows: the diameter of the flow splitting air pipes arranged between adjacent guide members close to the air inlet structure is greater than or equal to the diameter of the flow splitting air pipes arranged between adjacent guide members close to the air outlet structure.

[0020] The above content discloses a gas replacement device. The present invention also discloses a gas replacement method, which will be described below.

[0021] A method for gas replacement in a closed optical path system, applying the above gas replacement structure, supplies gas to the air inlet of the closed optical path through the diversion structure. The gas passes through the closed optical path and is discharged from the air outlet and discharged away through another diversion structure.

[0022] Compared with the prior art, some beneficial effects of the disclosed technical solution of the present invention include:

[0023] The present invention uses a diversion device with a multi-layer array arrangement of air holes for gas replacement, which can form a relatively uniform air flow distribution in the closed optical path channel, reduce the gas flow rate, effectively prevent the risk of minute dust being adsorbed onto the mirror surface due to a large air flow rate in the closed channel, can control the magnitude of the turbulence intensity inside the channel, and effectively reduce the phase distortion caused by non-uniform gas density distribution; it can increase the effective gas replacement area, shorten the replacement time, and save gas consumption. Description of the Drawings

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, so it should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic diagram of the overall structure of one perspective of the flow guiding structure.

[0026] Figure 2 It is a schematic diagram of the overall structure of another perspective of the flow guiding structure.

[0027] Figure 3 It is a schematic diagram of the layer structure of the flow guiding structure.

[0028] Figure 4 It is a schematic diagram of the overall structure of the flow guiding device provided at the air inlet of the closed optical path channel.

[0029] Figure 5 It is a schematic side view structure of the flow guiding device provided at the air inlet of the closed optical path channel.

[0030] Figure 6 It is the time-dependent curve of the relative humidity of the flow guiding device, the comparative flow guiding device, and the actual flow guiding device.

[0031] Figure 7 It is the time-dependent curve of the speed of the flow guiding device, the comparative flow guiding device, and the actual flow guiding device.

[0032] In the above-mentioned drawings, the meanings of each label are as follows:

[0033] 1. Air intake structure; 2. Shunt structure; 3. Flow guiding member; 4. Closed optical path channel; 5. Flow guiding structure; 6. Air outlet. Specific embodiments

[0034] The following further explains the present invention in conjunction with the drawings and specific embodiments.

[0035] In view of the situation that in the existing high-energy laser transmission process, the heat effect accumulated in the transmission path causes laser deterioration, the following embodiments are used for optimization and improvement to overcome the defects in the prior art.

[0036] Embodiment

[0037] As Figures 1 to 5 shown, this embodiment provides a gas replacement structure for a closed optical path system, which is applied to a closed optical path and includes:

[0038] A closed optical path channel 4, provided with an air inlet and an air outlet 6;

[0039] A number of flow guiding structures 5 are respectively arranged at the air inlet and the air outlet; the flow guiding structure 5 includes at least three layers of flow guiding members 3 arranged at intervals continuously, the inside of the flow guiding member 3 is a gas cavity, and a number of flow splitting structures 2 are communicated and arranged between adjacent flow guiding members 3; an air inlet structure 1 and an air outlet structure are respectively arranged on the frontmost and the rearmost flow guiding members 3 and are used for communicating and closing an optical path or an air flow path.

[0040] Preferably, the closed optical path channel 4 in this embodiment includes a Z-shaped channel composed of four cavity channels and five sub-pipes.

[0041] The above-disclosed gas replacement structure aims to provide uniform dry gas for the closed optical path, so that the gas entering the closed optical path can avoid the thermal effect under the high-energy laser environment and affect the propagation of the laser. The flow guiding structure 5 enables the air flow to enter the closed optical path uniformly, avoids the turbulent flow situation through the guidance of the flow guiding structure 5, and can complete the gas replacement quickly and efficiently, and can improve the transmission effect of the high-energy laser closed optical path.

[0042] In this embodiment, as the gas guiding structure, the feasible solutions for the flow guiding member 3 are not uniquely limited. This embodiment is optimized and one of the feasible options is adopted: the flow guiding member 3 includes a flow guiding plate. When adopting such a solution, the flow guiding plate can provide a relatively wide surface structure, and the gas cavity inside makes the gas uniform, which is convenient for maintaining a stable optical path environment in the subsequent closed optical path.

[0043] Preferably, in this embodiment, the structure of the flow guiding member 3 is regular to facilitate the elimination of the turbulent flow in the air flow. Specifically, this embodiment is optimized and one of the feasible options is adopted: the thickness of the flow guiding member 3 is uniform and the thickness is 5 mm to 50 mm, and the length and width of the flow guiding member 3 are at least 10 times the thickness of the flow guiding member 3. When adopting such a solution, the control of the length and width of the flow guiding member 3 can provide a sufficiently large gas cavity area, which is more convenient for eliminating the turbulent flow of the gas.

[0044] In this embodiment, the air inlet structure 1 and the air outlet structure are not uniquely limited, and a variety of feasible solutions can be adopted. Here, one of the feasible options is optimized and given: the air inlet structure 1 and the air outlet structure include a number of flow guiding air holes, and the air inlet structure 1 and the air outlet structure are symmetrical. When adopting such a solution, the flow guiding air holes can be evenly distributed on the end face of the outer guiding member, so that the gas entering the guiding member can be more uniform, reducing the initial turbulent flow and becoming more stable after flowing through the subsequent guiding members; it can also stably control the pressure distribution in the closed optical path channel 4 and effectively reduce the phase distortion problem caused by the non-uniform pressure distribution resulting in the non-uniform gas density distribution.

[0045] In this embodiment, the setting of the diversion air holes is further optimized. Referring to a feasible option as follows: the number of the diversion air holes is 1 to 10, and the aperture of the diversion air holes is 5 mm to 15 mm. When such a scheme is adopted, the more the number of the diversion air holes and the smaller the aperture, the smoother the airflow entering the guiding member, and the more controllable the gas flow rate and the ventilation time.

[0046] Preferably, in this embodiment, the number of the diversion air holes is four.

[0047] In this embodiment, the flow splitting structure 2 is used to guide the airflow in one guiding member to the adjacent guiding member, making the airflow denser to eliminate turbulence and reach a stable state. Here, the flow splitting structure 2 is optimized and a feasible option is adopted as follows: the flow splitting structure 2 includes a plurality of flow splitting air pipes distributed in an array, and the pipe diameter of the flow splitting air pipes is smaller than the aperture of the diversion air holes. When such a scheme is adopted, the flow splitting air pipes are evenly distributed between two adjacent guiding members.

[0048] Preferably, in this embodiment, the pipe diameter of the flow splitting air pipes adopted is within a suitable range. Specifically, the pipe diameter of the flow splitting air pipes is 1 mm to 10 mm.

[0049] In order to improve the effect of gas guiding and splitting, the arrangement of the flow splitting structure 2 is improved. Here, a feasible option is adopted as follows: the number of the flow splitting air pipes arranged between the adjacent guiding members 3 close to the air inlet structure 1 is greater than or equal to the number of the flow splitting air pipes arranged between the adjacent guiding members 3 close to the air outlet structure.

[0050] Preferably, in this embodiment, the flow splitting structure 2 is further optimized and a feasible option is adopted as follows: the pipe diameter of the flow splitting air pipes arranged between the adjacent guiding members 3 close to the air inlet structure 1 is greater than or equal to the pipe diameter of the flow splitting air pipes arranged between the adjacent guiding members 3 close to the air outlet structure.

[0051] Embodiment 2

[0052] The content of the above embodiment discloses a gas replacement device. This embodiment discloses a gas replacement method, which will be described below.

[0053] A method for gas replacement in a closed optical path system, applying the gas replacement structure of the above embodiment, supplies gas to the air inlet of the closed optical path through the flow guiding structure 5. The gas is discharged from the air outlet 6 after passing through the closed optical path and is discharged through another flow guiding structure 5.

[0054] An example is given to illustrate the effect of gas replacement using this gas replacement structure.

[0055] The main gas component that causes the gas thermal effect in the closed optical path channel is water vapor. This case mainly discusses the problem of water vapor replacement. In this case, the closed Coudé optical path channel of a high-power laser emission system is used as the object of discussion. The laser transmission distance is 3 meters. The gas to be replaced is air with a relative humidity of 50%, and the replacement gas is high-purity nitrogen. The initial pressure of the closed optical path channel is 0.1 MPa (atmospheric pressure), and the relative humidity index is 1%.

[0056] In this case, three gas replacement models are selected as the objects of discussion. The first replacement model mainly includes the inlet and outlet pipes and the Coudé optical path channel part; the second replacement model mainly includes the inlet and outlet pipes, a diversion device without stratified design, and the Coudé optical path channel part; the third replacement model mainly includes the inlet and outlet pipes, a diversion device with stratified design, and the Coudé optical path channel part. The first gas replacement method is commonly used. The second gas replacement device and method are used to compare the advantages and disadvantages of the stratified design. The third gas replacement device and method are the gas replacement structures in Example 1. The three gas replacement structures and methods are respectively referred to as the non-diversion device, the comparison diversion device, and the actual diversion device in this case.

[0057] This case includes the following steps:

[0058] (1) Structural modeling

[0059] The structural modeling steps of the actual diversion device design are as follows:

[0060] In the first step, according to the feasibility of the environmental gas supply of the high-power laser emission system, the sizes of the inlet and outlet gas pipes are determined. The diameters of the four inlet and outlet gas pipes are all 10 mm, and the pipe lengths are not the key objects of discussion.

[0061] In the second step, in order to form a low-flow-rate and relatively uniform airflow field distribution, a first-layer rectangular diversion plate is designed behind the inlet end. The thickness of the diversion plate is 20 mm, and the ratio of the length and width of the diversion plate to the thickness is 10:1.

[0062] In the third step, a first-layer shunt gas pipe with a uniform array arrangement is designed behind the first-layer diversion plate. The number of shunt gas pipes is 20, the pipe diameter is 5 mm, and the length is 5 mm;

[0063] In the fourth step, a second-layer diversion plate is designed behind the first-layer shunt gas pipe. The structural parameters of the second-layer diversion plate are the same as those of the first-layer diversion plate;

[0064] In the fifth step, a second-layer shunt gas pipe with a uniform array arrangement is designed behind the second-layer diversion plate. In this case, the simulation calculation shows that the structural parameters of the second-layer shunt gas pipe are the same as those of the first-layer shunt gas pipe;

[0065] In the sixth step, a third-layer diversion plate is designed behind the second-layer shunt gas pipe. The structural parameters of the third-layer diversion plate are the same as those of the second-layer diversion plate;

[0066] Step 7: Establish a closed optical path structure channel, which mainly includes five sub-pipeline channels and four cavity channels. The cavity channels contain lens structure domains.

[0067] Step 8: Arrange four gas outlet pipes at the top of the fourth cavity channel. The structural parameters of the gas outlet pipes are the same as those of the gas inlet pipes.

[0068] The structural modeling for comparison and simulation in this case is as follows. The structure without a flow guiding device mainly includes the gas inlet and outlet pipes and the Coudé optical path channel part. The comparison flow guiding device mainly includes the gas inlet and outlet pipes, the flow guiding device without layered design, and the Coudé optical path channel part. The flow guiding device without layered design is a single-layer design, and its thickness is the sum of the total thickness of the three-layer flow guiding plates and the two-layer flow dividing gas pipes of the actual flow guiding device model.

[0069] (2) Simulation calculation

[0070] The laser transmission distance is 3 meters. The gas to be replaced is air with a relative humidity of 50%. The replacement gas is high-purity nitrogen. The initial pressure of the closed optical path channel is 0.1 MPa (atmospheric pressure), and the relative humidity index is 1%.

[0071] The gas replacement model flow rates of the structure without a flow guiding device, the comparison flow guiding device, and the actual flow guiding device are 0.25 L / min, 0.25 L / min, and 5 L / min respectively. The calculation time is classified into 180 min, 210 min, and 60 min.

[0072] (3) Calculation results

[0073] During the gas replacement process, due to the non-uniformity of the inlet air flow velocity, it is easy to cause non-uniform distribution of the air flow in the closed optical path, resulting in non-uniform distribution of gas density and temperature locally, and then generating non-uniform distribution of refractive index, which affects the transmission of laser in the gas and finally introduces optical path difference. The gas replacement efficiency, the velocity uniformity and the maximum value in the closed optical path during the replacement process are used as the evaluation indexes of this scheme.

[0074] Figure 6 The dependence curve of relative humidity on time shows that the replacement times required for the structure without a flow guiding device, the comparison flow guiding device, and the actual flow guiding device to reach a relative humidity of 1% are 161 min, 189 min, and 45 min respectively. Figure 7 The dependence curve of the maximum velocity on time shows that the maximum values of the air flow velocity in the optical path distributed by the three methods, namely the structure without a flow guiding device, the comparison flow guiding device, and the actual flow guiding device, are all controlled below 0.1 m / s. The calculation results show that the actual flow guiding device with layered flow guiding design has the advantages of high replacement efficiency, uniform velocity distribution, and controllability.

[0075] The above are the implementation manners listed in this embodiment. However, this embodiment is not limited to the above optional implementation manners. Those skilled in the art can obtain many other implementation manners by arbitrarily combining the above manners. Anyone can obtain various other forms of implementation manners under the inspiration of this embodiment. The above specific implementation manners should not be construed as limiting the protection scope of this embodiment. The protection scope of this embodiment shall be defined by the claims.

Claims

1. A gas replacement structure for a closed optical path system, which is applied to a closed optical path, and is characterized in that, Comprising: A closed optical path channel (4) provided with an air inlet and an air outlet (6); A number of flow guiding structures (5) respectively arranged at the air inlet and the air outlet (6); the flow guiding structure (5) includes at least three layers of continuously spaced flow guiding members (3), the interior of the flow guiding member (3) is a gas chamber, and a number of flow splitting structures (2) are communicatively arranged between adjacent flow guiding members (3); an air inlet structure (1) and an air outlet structure are respectively arranged on the foremost and the last flow guiding members (3) and are used for communicating with the closed optical path channel (4) or the air flow path; The air inlet structure (1) and the air outlet structure include a number of flow guiding air holes, and the air inlet structure (1) and the air outlet structure are symmetrical; The flow splitting structure (2) includes a number of flow splitting air pipes arranged in an array, and the pipe diameter of the flow splitting air pipe is smaller than the aperture diameter of the flow guiding air hole; The number of the flow splitting air pipes is greater than the number of the flow guiding air holes.

2. The gas replacement structure of the closed optical path system according to claim 1, wherein: The flow guiding member (3) includes a flow guiding plate.

3. The gas replacement structure of the closed optical path system according to claim 1 or 2, characterized in that: The flow guiding member (3) has a uniform thickness of 5 mm to 50 mm, and the length and width of the flow guiding member (3) are at least 10 times the thickness of the flow guiding member (3).

4. The gas replacement structure of the closed optical path system according to claim 1, characterized in that: The number of the flow guiding air holes is 1 to 10, and the aperture diameter of the flow guiding air hole is 5 mm to 15 mm.

5. The gas replacement structure of the closed optical path system according to claim 1, wherein: The pipe diameter of the flow splitting air pipe is 1 mm to 10 mm.

6. The gas replacement structure of the closed optical path system according to claim 5, characterized in that: The number of the flow splitting air pipes arranged between adjacent flow guiding members (3) near the air inlet structure (1) is greater than or equal to the number of the flow splitting air pipes arranged between adjacent flow guiding members (3) near the air outlet structure.

7. The gas replacement structure of the closed optical path system according to claim 6, characterized in that: The pipe diameter of the flow splitting air pipes arranged between adjacent flow guiding members (3) near the air inlet structure (1) is greater than or equal to the pipe diameter of the flow splitting air pipes arranged between adjacent flow guiding members (3) near the air outlet structure.

8. A method for gas replacement in a closed optical path system, characterized in that: Applying the gas replacement structure according to any one of claims 1 to 7, supplying gas to the air inlet of the closed optical path through the flow guiding structure (5), and after the gas passes through the closed optical path channel (4), exhausting the gas from the air outlet (6) and discharging the gas away through another flow guiding structure (5).

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