In-situ observation device for cryogenic fluid

Abstract

The utility model relates to the technical field of observation devices, and provides an in-situ observation device for cryogenic fluid, which comprises a two-phase flow generation mechanism, an observation mechanism and a vacuum cover, the two-phase flow generation mechanism comprises a cryostat, a first cooling table and a runner pipe, and the runner pipe is arranged on the first cooling table; the observation mechanism comprises a mounting base, an objective lens, a light-transmitting plate and a camera shooting assembly, the light-transmitting plate is arranged on the mounting base and is in sealed connection with the mounting base, and the objective lens and the camera shooting assembly are arranged on the mounting base and located on the two opposite sides of the light-transmitting plate respectively; the vacuum cover covers the two-phase flow generation mechanism and the objective lens and is in sealed connection with the mounting seat, and the two ends of the runner pipe extend out of the vacuum cover and are in sealed connection with the vacuum cover. The objective lens and the runner pipe are both located in a low-temperature environment, there is no glass plate or other separators between the objective lens and the runner pipe, and definition and accuracy of visual research can be ensured. Moreover, the vacuum cover and the mounting seat are matched to form the vacuum cavity, and the objective lens is positioned in the vacuum cavity, so that the problem of heat leakage can be effectively avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to observation device technical field especially relates to a kind of in-situ observation device of low temperature fluid. BACKGROUND

[0002] Low temperature fluid is widely used in aerospace, energy, chemical industry and medical fields, for example, liquid nitrogen, as a low-cost, safe and rapid cooling low temperature fluid, is mainly used in high-temperature superconducting magnet cooling, high-temperature alloy and fiber-reinforced composite material ultra-low temperature processing cooling, low-temperature application of high-power device liquid cooling heat exchange, energy storage power station fire prevention engineering and superconducting composite energy pipeline and other scenes. As a small latent heat of vaporization refrigerant, liquid nitrogen is easily heated to boil and vaporize to form liquid nitrogen-nitrogen vapor two-phase flow, resulting in fluctuations in flow parameters, and poor cooling effect. Therefore, it is particularly important to study the flow and heat transfer characteristics of liquid nitrogen-nitrogen vapor two-phase flow.

[0003] Currently, the research techniques for liquid nitrogen-nitrogen vapor two-phase flow mainly include model prediction, numerical simulation and experimental analysis, which cannot analyze the physical phenomena during operation. Some related technologies propose visual research techniques, which specifically produce low temperature in the sample chamber, pass the fluid to be studied into the sample chamber, and open a window in the side wall of the sample chamber. An observation assembly is arranged outside the sample chamber opposite the window, and the low temperature fluid in the sample chamber is observed through the observation assembly. The setting of the window will cause heat leakage, affecting the accuracy of the observation results. If the thickness of the window glass is increased, the clarity and accuracy of the observation will be affected.

[0004] Therefore, how to solve the problem of heat leakage or poor observation clarity during visual research of low temperature fluid has become an important technical problem for technicians in the field to solve. UTILITY MODEL CONTENT

[0005] The utility model provides a kind of in-situ observation device of low temperature fluid to solve the defect of heat leakage or poor observation clarity during visual research of low temperature fluid.

[0006] The utility model provides a kind of in-situ observation device of low temperature fluid, comprising:

[0007] The two-phase flow generating mechanism includes a cryostat, a first cold table and a flow tube, the flow tube is adapted for fluid to pass through, the flow tube is arranged on the first cold table, the cryostat is adapted to provide cold to the first cold table, and the first cold table is adapted to transfer cold to the flow tube.

[0008] The observation mechanism comprises a mounting base, an objective lens, a light transmission plate and a camera assembly, the light transmission plate is arranged on the mounting base, the light transmission plate is in sealed connection with the mounting base, the objective lens and the camera assembly are arranged on the mounting base, and the objective lens and the camera assembly are respectively located on two opposite sides of the light transmission plate, and the objective lens faces the flow pipe on the first cold table.

[0009] A vacuum cover is arranged outside the two-phase flow generating mechanism and the objective lens, the vacuum cover is in sealed connection with the mounting base, and two ends of the flow pipe extend to the outside of the vacuum cover and are in sealed connection with the vacuum cover.

[0010] The low-temperature fluid in-situ observation device also comprises:

[0011] A first cold lead is arranged between the cold end of the low-temperature thermostat and the objective lens, and the first cold lead is adapted to transmit the cold energy of the cold end of the low-temperature thermostat to the objective lens.

[0012] The low-temperature fluid in-situ observation device also comprises:

[0013] The low-temperature fluid in-situ observation device also comprises:

[0014] A second cold lead is arranged between the cold end of the low-temperature thermostat and the first cold table, and the second cold lead is adapted to transmit the cold energy of the cold end of the low-temperature thermostat to the first cold table.

[0015] The low-temperature fluid in-situ observation device also comprises:

[0016] The cold lead rod is provided with at least two first connecting holes at one end close to the objective lens, the first connecting holes are distributed along the axial direction of the cold lead rod, the first cold table is provided with a connecting portion, the connecting portion is provided with a second connecting hole, and the second connecting hole is adapted to be connected to any one of the first connecting holes through a connecting bolt.

[0017] The low-temperature fluid in-situ observation device also comprises:

[0018] The first vacuum cover is arranged outside the low-temperature thermostat.

[0019] A second vacuum cover is arranged outside the first cold table and the flow pipe, a vacuum channel is formed between the second vacuum cover and the first vacuum cover for the second cold lead to pass through, and an opening is arranged on the second vacuum cover and faces the first cold table, so that the objective lens is close to or away from the flow pipe through the opening.

[0020] A vacuum cylinder is arranged between the second vacuum cover and the mounting seat, one end of the vacuum cylinder is sealingly connected with the opening of the second vacuum cover, and the other end is sealingly connected with the mounting seat.

[0021] According to the in-situ observation device for low-temperature fluid, the sealing structure is arranged between the second vacuum cover and the flow pipe, and the sealing structure comprises:

[0022] A connecting pipe is arranged on the second vacuum cover, and the connecting pipe is suitable for the flow pipe to enter and exit the second vacuum cover.

[0023] An end cover is arranged on one end of the connecting pipe away from the second vacuum cover, the end cover is sealingly connected with the connecting pipe, and the end cover is provided with a through hole for the flow pipe to pass through.

[0024] A sealing ring is sleeved on the outside of the flow pipe, and the sealing ring is tightly attached to the flow pipe.

[0025] A pressing member is arranged on one side of the end cover away from the connecting pipe, the pressing member is threadedly connected with the end cover, and the pressing member is suitable for pressing the sealing ring to the end cover.

[0026] According to the in-situ observation device for low-temperature fluid, the vacuum cylinder comprises a first flexible bellows.

[0027] According to the in-situ observation device for low-temperature fluid, the low-temperature thermostat comprises:

[0028] A refrigerator has a primary cold head and a secondary cold head, at least the primary cold head and the secondary cold head are inserted into the first vacuum cover, and the secondary cold head is provided with a cold head heat exchanger.

[0029] A first cold shield is arranged in the first vacuum cover, the first cold shield is arranged outside the primary cold head, and the first cold shield is sealingly connected to the first vacuum cover through an adiabatic cylinder.

[0030] A second cold shield is arranged in the first vacuum cover, the second cold shield is arranged outside the second cold head, the second cold shield is connected to the first cold shield through the cold conducting ring, and the second cold shield is provided with a second cold table at one end away from the first cold shield, the second cold table is adapted to be connected to the second cold conducting element, and the cold conducting capacity of the second cold shield is lower than that of the second cold conducting element.

[0031] A helium source is adapted to fill the space between the first cold shield and the primary cold head with helium.

[0032] A third cold shield is arranged in the first vacuum cover, the third cold shield is arranged outside the second cold shield, one end of the third cold shield is closed, and the other end is connected to the cold conducting ring.

[0033] A fourth cold shield is arranged in the vacuum channel, the fourth cold shield is arranged outside the second cold conducting element, one end of the fourth cold shield extends to the first vacuum cover and is connected to the third cold shield, and the other end of the fourth cold shield extends into the second vacuum cover.

[0034] According to the low-temperature fluid in-situ observation device provided by the utility model, further comprising:

[0035] An optical damping platform, the first vacuum cover and the second vacuum cover are arranged on the optical damping platform.

[0036] An air floating damping support has a support table and a support frame for supporting the support table, the body of the refrigerator is arranged above the support table, the primary cold head and the secondary cold head extend below the support table, and the lower end of the support frame is provided with an air floating damper.

[0037] A second flexible bellows is arranged between the support table and the first vacuum cover.

[0038] The in-situ observation device for low-temperature fluid provided by the utility model, including two-phase flow generating mechanism, observation mechanism and vacuum cover. Two-phase flow generating mechanism includes cryostat, first cold table and flow pipe, flow pipe is used for fluid passing. Flow pipe is arranged in first cold table, cryostat is used for providing cold quantity to first cold table, first cold table is used for transmitting cold quantity to flow pipe, and then cold quantity is transmitted to fluid in flow pipe, temperature of fluid is reduced, and low-temperature fluid is formed. Observation mechanism includes mounting seat, objective lens, light transmission plate and camera assembly, light transmission plate is arranged in mounting seat, and light transmission plate is sealingly connected with mounting seat. Objective lens and camera assembly are both arranged in mounting seat, and objective lens and camera assembly are respectively located on two sides of light transmission plate opposite to each other, objective lens is directly opposite to flow pipe on first cold table, and camera assembly can obtain the image of low-temperature fluid at the position opposite to objective lens through light transmission plate, so that the visualized research on low-temperature fluid in flow pipe is realized. Vacuum cover is arranged outside two-phase flow generating mechanism and objective lens, vacuum cover is sealingly connected with mounting seat, and both ends of flow pipe extend to the outside of vacuum cover, and flow pipe is sealingly connected with vacuum cover. Vacuum cover and mounting seat cooperate to form vacuum cavity, vacuumization treatment is carried out on vacuum cavity, then the temperature of vacuum cavity and first cold table is reduced to target temperature by cryostat, then medium is introduced into flow pipe outside vacuum cover, and low-temperature fluid is formed when medium flows in flow pipe to the position of first cold table. The image of low-temperature fluid at the position opposite to objective lens can be obtained by starting camera assembly, so that the visualized research on low-temperature fluid in flow pipe is realized. In this way, objective lens and flow pipe are both arranged in low-temperature environment, and there is no glass plate or other separator between them, so that the clarity and accuracy of visualized research can be ensured. Moreover, vacuum cover and mounting seat cooperate to form vacuum cavity, and objective lens is located in the vacuum cavity, so that the problem of heat leakage can be effectively avoided, and the problem of poor clarity during visualized research on low-temperature fluid is solved. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical scheme in the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description, and obviously, the drawings in the following description are some embodiments of the utility model, and for ordinary skilled in the art, other drawings can also be obtained according to these drawings without creating labor.

[0040] Figure 1 It is the structure schematic diagram of the in-situ observation device for low-temperature fluid provided by the utility model.

[0041] Figure 2 It is the sectional view of the in-situ observation device for low-temperature fluid provided by the utility model at one section position (optical damping platform and air floating damping support are not shown).

[0042] Figure 3 It isFigure 1 A magnified view of the X position in the middle.

[0043] Figure 4 This is a cross-sectional view of the in-situ observation device for cryogenic fluids provided by this utility model at another cross-sectional location.

[0044] Figure 5 This is a schematic diagram showing the relative positions of the flow tube, the first cold stage, and the objective lens provided by this utility model.

[0045] Figure 6 This is a schematic diagram of the structure of the first cold platform provided by this utility model.

[0046] Figure 7 This is a schematic diagram of the sealing structure between the flow tube and the second vacuum hood provided by this utility model.

[0047] Figure label:

[0048] 1. First cooling stage; 2. Flow pipe; 3. Mounting base; 4. Objective lens; 5. Light-transmitting plate; 6. Receiving groove; 7. Cooling guide rod; 8. First connecting hole; 9. Connecting part; 10. Second connecting hole; 11. First vacuum hood; 12. Second vacuum hood; 13. Vacuum channel; 14. Opening; 15. Vacuum cylinder; 16. Connecting pipe; 17. End cap; 18. Sealing ring; 19. Clamping component; 20. Refrigeration unit; 21. First-stage cold head; 22. 23. Secondary cold head; 24. Cold head heat exchanger; 25. First cold shield; 26. Insulation cylinder; 27. Second cold shield; 28. Second cold stage; 29. ​​Helium source; 20. Third cold shield; 31. Fourth cold shield; 32. Optical vibration damping platform; 33. Support platform; 34. Support frame; 35. Air flotation vibration damper; 36. Second flexible bellows; 37. Objective lens moving mechanism; 38. Beam splitter and light source; 39. CCD camera; 30. Inflatable base. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0050] The following is combined Figures 1 to 7 This invention describes an in-situ observation device for cryogenic fluids.

[0051] like Figures 1 to 7 As shown in the figure, the in-situ observation device for cryogenic fluids provided in this embodiment of the present invention includes a two-phase flow generation mechanism, an observation mechanism, and a vacuum hood.

[0052] Specifically, the two-phase flow generating mechanism comprises a cryostat, a first cold stage 1 and a flow tube 2.

[0053] The flow tube 2 is used for passing fluid, and the flow tube 2 is arranged on the first cold stage 1. The cryostat is used for providing cold energy to the first cold stage 1, the first cold stage 1 is used for transferring cold energy to the flow tube 2, and then transferring the cold energy to the fluid in the flow tube 2, reducing the temperature of the fluid, and forming low-temperature fluid.

[0054] The observation mechanism comprises a mounting seat 3, an objective lens 4, a light-transmitting plate 5 and a camera assembly.

[0055] The light-transmitting plate 5 is arranged on the mounting seat 3, and the light-transmitting plate 5 is sealingly connected with the mounting seat 3. The objective lens 4 and the camera assembly are both arranged on the mounting seat 3, and the objective lens 4 and the camera assembly are respectively located on two opposite sides of the light-transmitting plate 5, and the objective lens 4 directly faces the flow tube 2 on the first cold stage 1.

[0056] In order to realize the observation of the fluid in the flow tube 2, the part of the flow tube 2 located on the first cold stage 1 is arranged in a transparent manner, and the specific material can be transparent glass.

[0057] The camera assembly can obtain the image of the low-temperature fluid at the position faced by the objective lens 4 through the light-transmitting plate 5, so as to realize the visualized research on the low-temperature fluid in the flow tube 2.

[0058] The vacuum cover is arranged outside the two-phase flow generating mechanism and the objective lens 4, and the vacuum cover is sealingly connected with the mounting seat 3. The two ends of the flow tube 2 extend to the outside of the vacuum cover, and the flow tube 2 is sealingly connected with the vacuum cover.

[0059] The vacuum cover cooperates with the mounting seat 3 to form a vacuum cavity. The vacuum cavity is subjected to vacuumizing treatment, and then the temperature of the vacuum cavity and the first cold stage 1 is reduced to a target temperature by using the cryostat. Then, the medium is introduced into the flow tube 2 outside the vacuum cover, and the medium will form low-temperature fluid in the flow tube 2 when flowing to the position of the first cold stage 1. The camera assembly can obtain the image of the low-temperature fluid at the position faced by the objective lens 4, so as to realize the visualized research on the low-temperature fluid in the flow tube 2.

[0060] In this way, the objective lens 4 and the flow tube 2 are both arranged in a low-temperature environment, and there is no glass plate or other separator between them, which can ensure the clarity and accuracy of the visualized research. Moreover, the vacuum cover cooperates with the mounting seat 3 to form a vacuum cavity, and the objective lens 4 is located in the vacuum cavity, which can effectively avoid the problem of heat leakage, and solve the problem of poor clarity or heat leakage when performing visualized research on low-temperature fluid.

[0061] It should be noted that the fluid can be, but is not limited to, hydrogen, liquefied natural gas, nitrogen, oxygen, neon, etc. When the vacuum chamber and the first cold table 1 are cooled by the cryostat, the target temperature can be determined according to the composition of the fluid and the state to be observed. For example, when the flow and heat exchange characteristics of the liquid nitrogen-nitrogen vapor two-phase flow need to be observed, the temperature of the vacuum chamber and the first cold table 1 needs to be controlled at about 77 Kelvin (symbol bit K).

[0062] In the embodiment of the utility model, the in-situ observation device of low temperature fluid further includes a first cold guide, the first cold guide is arranged between the cold end of the cryostat and the objective lens 4, and the first cold guide is used for transmitting the cold quantity of the cold end of the cryostat to the objective lens 4 to reduce the temperature of the objective lens 4, so that the heat leakage problem of the objective lens 4 can be further reduced.

[0063] In the embodiment of the utility model, the accommodating groove 6 is arranged on the first cold table 1, and the flow pipe 2 is arranged in the accommodating groove 6. Figure 5 And Figure 6 The accommodating groove 6 is a through groove arranged on the first cold table 1, and the cross-sectional shape of the accommodating groove 6 is close to the cross-sectional shape of the flow pipe 2.

[0064] In this way, after the flow pipe 2 is arranged in the accommodating groove 6, the outer side wall of the flow pipe 2 is in contact with the side wall of the accommodating groove 6, the contact area of the flow pipe 2 and the first cold table 1 is increased, and the cold conduction efficiency of the first cold table 1 to the flow pipe 2 can be improved.

[0065] In the embodiment of the utility model, the in-situ observation device of low temperature fluid further includes a second cold guide, the second cold guide is arranged between the cold end of the cryostat and the first cold table 1, and the second cold guide is used for transmitting the cold quantity of the cold end of the cryostat to the first cold table 1.

[0066] In this way, the cryostat and the first cold table 1 are arranged separately, the influence of the vibration of the cryostat on the first cold table 1 and the flow pipe 2 can be reduced, and the clarity and accuracy of observation can be ensured. Moreover, the modular design of the in-situ observation device of low temperature fluid is facilitated, the flexibility is higher, and the layout is facilitated.

[0067] In the embodiment, the second cold guide includes a cold guide rod 7, and the cold guide rod 7 is provided with a first connecting hole 8 at one end close to the objective lens 4. The first connecting hole 8 is provided with at least two first connecting holes 8, and each first connecting hole 8 is distributed along the axis direction of the cold guide rod 7. The first cold table 1 has a connecting portion 9, the connecting portion 9 is provided with a second connecting hole 10, and the second connecting hole 10 can be connected with any one of the first connecting holes 8 through a connecting bolt.

[0068] When the second connecting hole 10 is connected with different first connecting holes 8, the first cold table 1 and the cold lead 7 can have different relative positions, and can be adapted to different distances between the first cold table 1 and the cold end of the cryostat, which is beneficial to reduce the requirement for the precision of the relative position of the first cold table 1 and the cryostat, and is beneficial to reduce the requirement for the machining precision.

[0069] In the embodiment, the vacuum cover includes a first vacuum cover 11, a second vacuum cover 12 and a vacuum cylinder 15.

[0070] The first vacuum cover 11 is arranged outside the cryostat, and is used to reduce the loss of cold energy of the cold end of the cryostat to the outside and reduce heat leakage.

[0071] The second vacuum cover 12 is arranged outside the first cold table 1 and the flow-through pipe 2, and is used to reduce the loss of cold energy of the first cold table 1 and the flow-through pipe 2 to the outside and reduce heat leakage.

[0072] A vacuum passage 13 is formed between the second vacuum cover 12 and the first vacuum cover 11, and the second vacuum cover 12 and the first vacuum cover 11 are both connected with the vacuum passage 13. Referring to Figure 3 Extension pipes with flanges at the end portions can be respectively arranged on the first vacuum cover 11 and the second vacuum cover 12, and the two extension pipes are fastened and connected together by connecting bolts. In order to ensure sealing, a sealing gasket can be arranged between the two extension pipes. Figure 3 Only the butt joint mode of the two extension pipes is shown, and the sealing gasket and the connecting bolts are not shown. The second cold lead passes through the vacuum passage 13, and the second cold lead located in the vacuum passage 13 extends to the first vacuum cover 11 at one end to be connected with the cold end of the cryostat, and extends to the second vacuum cover 12 at the other end to be connected with the first cold table 1.

[0073] An opening 14 is arranged on the second vacuum cover 12, and the opening 14 is opposite to the first cold table 1 to allow the objective lens 4 to approach or move away from the flow-through pipe 2, so as to facilitate the adjustment of the distance between the objective lens 4 and the flow-through pipe 2.

[0074] The vacuum cylinder 15 is arranged between the second vacuum cover 12 and the mounting seat 3, and the vacuum cylinder 15 has a tubular structure with open ends. One end of the vacuum cylinder 15 is sealingly connected with the opening 14 of the second vacuum cover 12, and the other end is sealingly connected with the mounting seat 3. The vacuum cylinder 15 is used to reduce the loss of cold energy of the objective lens 4 to the outside and reduce heat leakage.

[0075] The vacuum cylinder 15, the second vacuum cover 12, the vacuum passage 13 and the first vacuum cover 11 are connected, so that the vacuum cylinder 15, the second vacuum cover 12, the vacuum passage 13 and the first vacuum cover 11 can be simultaneously subjected to vacuumizing operation by using the same vacuumizing device, which is convenient for operation and management.

[0076] Quick couplings can be arranged on the first vacuum cover 11 and the second vacuum cover 12 for connecting a vacuumizing device to realize vacuumizing operation.

[0077] In this embodiment, a sealing structure is arranged between the second vacuum cover 12 and the flow tube 2 to avoid the cold energy in the second vacuum cover 12 from being lost to the outside through the gap between the second vacuum cover 12 and the flow tube 2.

[0078] The sealing structure comprises a connecting tube 16, an end cover 17, a sealing ring 18 and a pressing member 19.

[0079] The connecting tube 16 is arranged on the second vacuum cover 12 and is used for the flow tube 2 to enter and exit the second vacuum cover 12.

[0080] The end cover 17 is arranged on the end of the connecting tube 16 away from the second vacuum cover 12 and is sealingly connected with the connecting tube 16. A through hole is arranged on the end cover 17 for the flow tube 2 to pass through. The sealing ring 18 is sleeved on the outside of the flow tube 2 and tightly abuts against the flow tube 2. The pressing member 19 is arranged on the side of the end cover 17 away from the connecting tube 16 and is threadedly connected with the end cover 17, so as to press the sealing ring 18 against the end cover 17, and the pressing member 19 and the end cover 17 tightly abut against the sealing ring 18 to realize sealing of the gap on the side of the flow tube 2.

[0081] In this way, the flow tube 2 and the second vacuum cover 12 are conveniently assembled and connected, and the sealing structure is a dynamic seal, which can allow the flow tube 2 to move relative to the second vacuum cover 12, the connecting tube 16, the end cover 17, the sealing ring 18 and the pressing member 19, can adapt to the relative position misalignment of the flow tube 2 and the second vacuum cover 12 caused by thermal expansion and contraction of the flow tube 2, and can reduce stress.

[0082] The camera assembly comprises an objective lens moving mechanism 36, a light splitter and light source 37 and a CCD camera 38, and the objective lens moving mechanism 36, the light splitter and light source 37 and the CCD camera 38 are arranged on the mounting base 3. The light splitter and light source 37 are used for providing light and adjusting light intensity, and the CCD camera 38 is used for acquiring the image of the low-temperature fluid at the position opposite to the objective lens 4. The position of the mounting base 3 is adjustable, and the objective lens moving mechanism 36 is used for adjusting the position of the mounting base 3 in the horizontal direction, the vertical direction and the longitudinal direction, so as to adjust the distance between the objective lens 4 and the flow tube 2 and make the objective lens 4 and the flow tube 2 face each other.

[0083] It should be noted that in the specific use process, the CCD camera 38 also needs to be connected with a display device to present the image information acquired by the CCD camera 38 on the display device, which is convenient for research.

[0084] In the embodiment, the vacuum cylinder 15 comprises a first flexible bellows, one end of the first flexible bellows is connected with the second vacuum cover 12, and the other end of the first flexible bellows is connected with the mounting seat 3. The first flexible bellows can be deformed, the deformation of the first flexible bellows can adapt to the displacement of the mounting seat 3 and the objective lens 4 relative to the second vacuum cover 12, and the sealing of the first flexible bellows and the second vacuum cover 12 and the sealing of the first flexible bellows and the mounting seat 3 are not affected.

[0085] In addition, the first flexible bellows realizes the flexible connection of the second vacuum cover 12 and the mounting seat 3, can also reduce the transmission of the vibration of the second vacuum cover 12 to the mounting seat 3 and the light splitter and the light source 37 and the CCD camera 38 located on the mounting seat 3, reduce the influence of the vibration on the camera assembly, and ensure the clarity and accuracy of the visualization research.

[0086] In the embodiment of the utility model, the low-temperature thermostat comprises a refrigerator 20, a first cold screen 24, a second cold screen 26, a helium source 28, a third cold screen 29 and a fourth cold screen 30.

[0087] The refrigerator 20 has a primary cold head 21 and a secondary cold head 22, and the temperature of the secondary cold head 22 is lower than that of the primary cold head 21. The refrigerator 20 can be a GM refrigerator or a GM type pulse tube refrigerator, and no low-temperature refrigerant is needed, so that the long-term stability and service life of the system are improved.

[0088] At least the primary cold head 21 and the secondary cold head 22 extend into the first vacuum cover 11, and the first cold screen 24 and the second cold screen 26 are arranged in the first vacuum cover 11. The first cold screen 24 is arranged outside the primary cold head 21 and is used for reducing the radiation heat leakage of the primary cold head 21 to the outside environment. The second cold screen 26 is arranged outside the secondary cold head 22 and is used for reducing the radiation heat leakage of the secondary cold head 22 to the outside environment.

[0089] The first cold screen 24 is sealingly connected to the first vacuum cover 11 through the heat insulation cylinder 25, the space between the first cold screen 24 and the primary cold head 21 and the space between the first cold screen 24 and the first vacuum cover 11 can be isolated, the transmission of the cold quantity of the first cold screen 24 to the first vacuum cover 11 is reduced, and the heat leakage is reduced.

[0090] Considering the heat insulation performance and mechanical performance of the heat insulation cylinder 25, the sealing connection of the heat insulation cylinder 25 and the first cold screen 24 and the sealing connection of the heat insulation cylinder 25 and the first vacuum cover 11, the material of the heat insulation cylinder 25 can be stainless steel.

[0091] The second cold screen 26 is connected to the first cold screen 24 through the cold conducting ring, and the second cold screen 26 is provided with a second cold table 27 at the end away from the first cold screen 24, and the second cold table 27 can seal the second cold screen 26. In this way, the space between the first cold screen 24 and the primary cold head 21 is in communication with the space between the second cold screen 26 and the secondary cold head 22, and is in a closed state.

[0092] The helium source 28 is used to fill the space between the first cold screen 24 and the primary cold head 21 with helium, and the helium can also flow into the space between the second cold screen 26 and the secondary cold head 22. The helium source 28 can be, but is not limited to, a helium storage tank.

[0093] The refrigerator 20 is started to provide a cold source. The temperature of the primary cold head 21 of the refrigerator 20 is higher than the temperature of the secondary cold head 22, and has a temperature gradient. The helium forms a circular convection heat exchange due to the thermal field difference, and realizes the reciprocating circulation cooling of the helium. The helium cooling forms liquid helium, which is gathered downward above the second cold table 27, and the liquid helium transmits the cold to the second cold table 27.

[0094] The second cold table 27 is used to be connected with the second cold conducting member, and the cold of the second cold table 27 can be transmitted to the first cold table 1 through the second cold conducting member.

[0095] The cold conducting capacity of the second cold screen 26 is lower than the cold conducting capacity of the second cold conducting member, and specifically can be as low as possible, so that the cold conducting capacity of the second cold screen 26 is much lower than the cold conducting capacity of the second cold conducting member, so that the cold of the second cold table 27 is transmitted to the first cold table 1 as much as possible, the cold of the second cold table 27 is reduced to the second cold screen 26 and the cold conducting ring, and the heat leakage is reduced.

[0096] The cold head heat exchanger 23 is arranged on the secondary cold head 22, and specifically can be a block structure of red copper material, has a strong cold conducting effect, and the block structure is provided with a plurality of fins, which can increase the contact area with the helium, and greatly improve the cooling efficiency of the secondary cold head 22 to the helium.

[0097] The third cold screen 29 is arranged in the first vacuum cover 11, and the third cold screen 29 is arranged outside the second cold screen 26. One end of the third cold screen 29 is closed, and the other end is connected to the cold conducting ring. The third cold screen 29 is located outside the second cold table 27, and is used to reduce the radiation heat leakage of the external environment to the second cold table 27.

[0098] The fourth cold screen 30 is arranged in the vacuum channel 13, and the fourth cold screen 30 is arranged outside the second cold conducting member, and is used to reduce the radiation heat leakage of the external environment to the second cold conducting member.

[0099] The fourth cold screen 30 extends to the first vacuum cover 11 at one end, and is connected with the third cold screen 29.

[0100] The fourth cold screen 30 is provided with a notch at a position corresponding to the first cold table 1, so that the first cold table 1 can pass through the fourth cold screen 30.

[0101] When the cold end of the cryostat is connected with the objective lens 4 by the first cold lead, the first cold lead can be connected with the fourth cold screen 30 of the cryostat.

[0102] In the embodiment of the utility model, the in-situ observation device of low temperature fluid further includes an optical damping platform 31, an air floating damping support and a second flexible bellows 35.

[0103] The optical damping platform 31 is arranged on the ground, and the first vacuum cover 11 and the second vacuum cover 12 are arranged on the optical damping platform 31.

[0104] The air floating damping support has a support table 32 and a support frame 33, and the support frame 33 is used for supporting the support table 32.

[0105] The body of the refrigerator 20 is arranged above the support table 32, the first-level cold head 21 and the second-level cold head 22 extend below the support table 32, and the first vacuum cover 11 is located below the support table 32.

[0106] The second flexible bellows 35 is arranged between the support table 32 and the first vacuum cover 11, one end of the second flexible bellows 35 is connected with the first vacuum cover 11, and the other end of the second flexible bellows 35 is connected with the support table 32. The second flexible bellows 35 can be deformed, and the second flexible bellows 35 realizes the flexible connection between the first vacuum cover 11 and the support table 32, can reduce the transmission of the vibration of the refrigerator 20 to the first vacuum cover 11, and further reduce the transmission of the vibration to the second vacuum cover 12 and the camera assembly, reduce the influence of the vibration on the camera assembly, and ensure the clarity and accuracy of the visualization research.

[0107] Therefore, in combination with the arrangement of the second flexible bellows 35 and the reciprocating circulation cooling of the helium, the cold energy of the refrigerator 20 is transferred to the second cold table 27, and the rigid connection between the refrigerator 20 and the second cold table 27 is avoided, so that the vibration of the refrigerator 20 is greatly reduced and transferred to the second cold table 27.

[0108] For the structure related to the helium source 28 filling the helium into the space between the primary cold head 21 and the first cold shield 24, the gas filling seat 39 can be arranged above the support table 32, and the gas filling seat 39 is in sealing connection with the support table 32. The gas filling seat 39 is provided with a gas filling channel, and the support table 32 is provided with a communication channel for communicating the gas filling channel and the space between the primary cold head 21 and the first cold shield 24. The helium source 28 is connected with the gas filling channel, and the helium passes through the gas filling channel of the gas filling seat 39 and the communication channel of the support table 32 in sequence, and then enters the space between the primary cold head 21 and the first cold shield 24.

[0109] It should be noted that the gas filling seat 39 is also provided with an exhaust channel, one end of the exhaust channel communicates with the space between the primary cold head 21 and the first cold shield 24, and the other end of the exhaust channel is connected with the vacuumizing device. When filling the helium into the space between the primary cold head 21 and the first cold shield 24, the space between the primary cold head 21 and the first cold shield 24 needs to be vacuumized first to exhaust the residual gas in the space between the primary cold head 21 and the first cold shield 24, so as to ensure the purity of the helium in the space between the primary cold head 21 and the first cold shield 24. In addition, when filling the helium into the space between the primary cold head 21 and the first cold shield 24, the gas washing operation can be performed, which is not described in detail.

[0110] In summary, in the embodiment of the utility model, in combination with the use of the refrigerator 20 and the sealing heat leakage prevention arrangement at each position, the in-situ observation device for low-temperature fluid can meet the observation of the fluid in the wide temperature range of 10-300K, and can cover the working temperature range of low-temperature fluid such as liquid hydrogen, liquid neon, liquid nitrogen, liquid oxygen and liquefied natural gas.

[0111] The use method of the in-situ observation device for low-temperature fluid provided in the embodiment is described below by taking the visualization research on the flow and heat exchange characteristics of the liquid nitrogen-nitrogen vapor two-phase flow as an example.

[0112] Firstly, the vacuumizing operation is performed by using the vacuumizing device, and the pressure in the first vacuum cover 11 and the second vacuum cover 12 is lower than 10 -3The temperature of the second vacuum cover 12 is then reduced to about 77K by the helium source 28. When the temperature of the second vacuum cover 12 reaches about 77K and is stable, nitrogen is introduced into the flow tube 2. When the nitrogen reaches the position of the flow tube 2 on the first cold stage 1, the nitrogen reaches a liquid nitrogen-nitrogen vapor two-phase flow state. The CCD camera 38 and the light source are started, and the position of the objective lens 4 is adjusted so that the CCD camera 38 can obtain the image of the low-temperature fluid at the position of the objective lens 4. The image obtained by the CCD camera 38 is presented by the display device, thereby realizing fine in-situ observation of the flow and heat exchange characteristics of the liquid nitrogen-nitrogen vapor two-phase flow.

[0113] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An in-situ observation device for cryogenic fluids, characterized in that, include: A two-phase flow generating mechanism includes a cryogenic thermostat, a first cold stage (1) and a flow pipe (2). The flow pipe (2) is adapted to allow fluid to pass through. The flow pipe (2) is disposed on the first cold stage (1). The cryogenic thermostat is adapted to provide cooling to the first cold stage (1). The first cold stage (1) is adapted to transfer cooling to the flow pipe (2). The observation mechanism includes a mounting base (3), an objective lens (4), a light-transmitting plate (5), and a camera assembly. The light-transmitting plate (5) is disposed on the mounting base (3) and is sealed to the mounting base (3). The objective lens (4) and the camera assembly are both disposed on the mounting base (3), and the objective lens (4) and the camera assembly are respectively located on opposite sides of the light-transmitting plate (5). The objective lens (4) faces the flow tube (2) on the first cold stage (1). A vacuum hood is provided outside the two-phase flow generating mechanism and the objective lens (4). The vacuum hood is sealed to the mounting base (3). Both ends of the flow tube (2) extend to the outside of the vacuum hood, and the flow tube (2) is sealed to the vacuum hood.

2. The in-situ observation device for cryogenic fluids according to claim 1, characterized in that, Also includes: A first cooling element is disposed between the cold end of the cryostat and the objective lens (4). The first cooling element is adapted to transfer the cold energy of the cold end of the cryostat to the objective lens (4).

3. The in-situ observation device for cryogenic fluids according to claim 1, characterized in that, The first cold table (1) is provided with a receiving groove (6), and the flow pipe (2) passes through the receiving groove (6).

4. The in-situ observation device for cryogenic fluids according to claim 1, characterized in that, Also includes: The second cooling element is disposed between the cold end of the low-temperature thermostat and the first cold stage (1). The second cooling element is adapted to transfer the cold energy of the cold end of the low-temperature thermostat to the first cold stage (1).

5. The in-situ observation device for cryogenic fluids according to claim 4, characterized in that, The second cooling component includes: A cooling rod (7) is provided with at least two first connecting holes (8) at one end near the objective lens (4). Each of the first connecting holes (8) is spaced apart along the axial direction of the cooling rod (7). The first cooling stage (1) has a connecting part (9). A second connecting hole (10) is provided on the connecting part (9). The second connecting hole (10) is adapted to be connected to any one of the first connecting holes (8) by a connecting bolt.

6. The in-situ observation device for cryogenic fluids according to claim 4, characterized in that, The vacuum chamber includes: The first vacuum shroud (11) is installed outside the cryogenic thermostat; The second vacuum hood (12) is provided outside the first cold stage (1) and the flow tube (2). A vacuum channel (13) is formed between the second vacuum hood (12) and the first vacuum hood (11) for the second cooling component to pass through. An opening (14) is provided on the second vacuum hood (12) facing the first cold stage (1). The opening (14) allows the objective lens (4) to approach or move away from the flow tube (2). A vacuum cylinder (15) is disposed between the second vacuum cover (12) and the mounting base (3). One end of the vacuum cylinder (15) is sealed to the opening (14) of the second vacuum cover (12), and the other end is sealed to the mounting base (3).

7. The in-situ observation device for cryogenic fluids according to claim 6, characterized in that, A sealing structure is provided between the second vacuum hood (12) and the flow tube (2), the sealing structure comprising: A connecting tube (16) is disposed in the second vacuum shroud (12), and the connecting tube (16) is adapted to allow the flow tube (2) to enter and exit the second vacuum shroud (12); An end cap (17) is provided at one end of the connecting tube (16) away from the second vacuum shroud (12). The end cap (17) is sealed to the connecting tube (16). The end cap (17) is provided with a through hole for the flow tube (2) to pass through. A sealing ring (18) is fitted around the outside of the flow tube (2), and the sealing ring (18) fits tightly against the flow tube (2); A clamping member (19) is disposed on the side of the end cap (17) away from the connecting pipe (16). The clamping member (19) is threadedly connected to the end cap (17). The clamping member (19) is adapted to press the sealing ring (18) against the end cap (17).

8. The in-situ observation device for cryogenic fluids according to claim 6, characterized in that, The vacuum cylinder (15) includes a first flexible bellows.

9. The in-situ observation device for cryogenic fluids according to any one of claims 6-8, characterized in that, The cryostat includes: The refrigerator (20) has a primary cold head (21) and a secondary cold head (22), at least the primary cold head (21) and the secondary cold head (22) extend into the first vacuum shroud (11), and the secondary cold head (22) is provided with a cold head heat exchanger (23). The first cold shield (24) is disposed inside the first vacuum cover (11). The first cold shield (24) covers the outside of the first-stage cold head (21). The first cold shield (24) is sealed to the first vacuum cover (11) through an insulation cylinder (25). The second cold screen (26) is disposed inside the first vacuum shroud (11). The second cold screen (26) covers the outside of the secondary cold head (22). The second cold screen (26) is connected to the first cold screen (24) through a cold-conducting ring. A second cold platform (27) is provided at the end of the second cold screen (26) away from the first cold screen (24). The second cold platform (27) is adapted to be connected to the second cold-conducting component. The cold-conducting capacity of the second cold screen (26) is lower than that of the second cold-conducting component. A helium source (28) is adapted to fill the space between the first cold screen (24) and the first-stage cold head (21) with helium. The third cold screen (29) is disposed inside the first vacuum shroud (11). The third cold screen (29) covers the outside of the second cold screen (26). One end of the third cold screen (29) is closed, and the other end is connected to the cooling ring. The fourth cold screen (30) is disposed in the vacuum channel (13). The fourth cold screen (30) covers the outside of the second cooling component. One end of the fourth cold screen (30) extends to the first vacuum cover (11) and is connected to the third cold screen (29). The other end of the fourth cold screen (30) extends into the second vacuum cover (12).

10. The in-situ observation device for cryogenic fluids according to claim 9, characterized in that, Also includes: An optical vibration damping platform (31) is provided, on which the first vacuum hood (11) and the second vacuum hood (12) are both disposed; The air-floating vibration damping bracket has a support platform (32) and a support frame (33) for supporting the support platform (32). The body of the refrigerator (20) is located above the support platform (32). The first-stage cold head (21) and the second-stage cold head (22) extend to the bottom of the support platform (32). An air-floating vibration damper (34) is provided at the lower end of the support frame (33). The second flexible corrugated pipe (35) is disposed between the support platform (32) and the first vacuum hood (11).

Images