Low-temperature cold air generating device and liquid nitrogen jet system

Abstract

The invention relates to the technical field of liquid nitrogen jet precooling, in particular to a low-temperature cold air generating device and a liquid nitrogen jet system.The low-temperature cold air generating device comprises a shell, and a plugging cone is arranged in the shell; an annular cavity is formed between the plugging cone and the inner wall of the shell, and a plurality of flow equalizing plates are arranged in the annular cavity; a liquid collecting ring is arranged on the shell in the circumferential direction, and the liquid collecting ring is connected with a liquid nitrogen source; and a plurality of jet holes are formed in the shell corresponding to the liquid collecting ring. The low-temperature cold air generating device is arranged to be in a side spraying mode of the annular wall face, so that in the whole low-temperature cold air generating process, liquid nitrogen does not make direct or indirect contact with air before entering the device; the problems of insufficient utilization of latent heat, poor two-phase flow stability of liquid nitrogen in the pipe and large structural local stress caused by heat exchange between the liquid nitrogen and air before spraying of the spraying holes are effectively solved, meanwhile, the device can meet the requirement of a scene with the high requirement for miniaturization of the device, and the application range is wide. The problems that an existing low-temperature cold air generating device is poor in phase change heat transfer and mass transfer uniformity and low in heat exchange efficiency are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of liquid nitrogen jet cooling, in particular to a low-temperature cold air generating device and a liquid nitrogen jet system. BACKGROUND

[0002] Liquid nitrogen jet cooling technology is a technology that mixes liquid nitrogen with high-temperature gas through spraying, uses the cold energy released by the latent heat and sensible heat of the rapid evaporation of liquid nitrogen to achieve rapid cooling, and then obtains low-temperature gas that meets the requirements in a short time. This technology is widely used in the fields of energy, electrical equipment, medical treatment, aerospace, etc.

[0003] In the prior art, the rapid evaporation of liquid nitrogen is usually realized by using an ejector or arranging a jet rod in a channel. The ejector mainly uses the principle of pressure reduction and acceleration of high-pressure gas (working fluid) to entrain the liquid nitrogen (induced fluid) in the boundary region under the action of turbulent diffusion to realize rapid mixing and heat exchange of the two fluids. However, the energy transfer efficiency of the ejector is low, and a large amount of energy is lost when the two fluids are mixed, and the liquid nitrogen cannot be uniformly mixed with the cooled gas, and cannot be completely evaporated in a limited space, so that the low-temperature gas at the outlet has low quality and is not easy to adjust. Although the liquid nitrogen jet cooling by arranging a jet rod in a channel overcomes the uniformity problem of phase change heat and mass transfer, the liquid nitrogen is easily vaporized to form two-phase flow in the jet rod, and then thermal choke occurs. In addition, the liquid nitrogen enters the channel again through the jet rod, causing a large local resistance loss, requiring a high pressure source on the liquid nitrogen side, and the liquid nitrogen jet rod in the channel cannot be scaled proportionally according to actual needs, which is not conducive to the miniaturization of the device. Therefore, the existing low-temperature cold air generating device developed by using liquid nitrogen jet cooling technology has the problems of incomplete atomization of liquid nitrogen, difficulty in adjusting the temperature of cold air, inability to realize miniaturization of the device, and high cost. Therefore, how to improve the comprehensive performance of the liquid nitrogen jet cooling device has become a technical problem to be solved by the technical personnel in the field. SUMMARY

[0004] In view of the poor phase change heat and mass transfer uniformity and low heat exchange efficiency of the low-temperature cold air generating device in the prior art, the present application provides a low-temperature cold air generating device and a liquid nitrogen jet system.

[0005] To achieve the above-mentioned purpose, the following technical solutions are adopted in the present application: The present application provides a low-temperature cold air generating device, which comprises a shell, wherein the shell is a cylindrical structure, and a plug cone is arranged inside the shell; an annular cavity is formed between the plug cone and the inner wall of the shell, and a plurality of flow uniforming plates are arranged in the annular cavity; a liquid collecting ring is arranged on the shell upstream of the plug cone in a circumferential direction, and the liquid collecting ring is connected to a liquid nitrogen source; and a plurality of jet holes are arranged on the shell corresponding to the liquid collecting ring.

[0006] Optionally, the plug cone comprises a thin-walled shell, and a plurality of support rods are arranged on the thin-walled shell and connected with the shell.

[0007] Optionally, the thin-walled shell has a streamlined cross section.

[0008] Optionally, the flow uniformizing plate is a ring-shaped flow uniformizing plate, and a plurality of flow uniformizing holes are arranged on the flow uniformizing plate.

[0009] Optionally, the flow uniformizing holes are staggered from the inner ring to the outer ring of the flow uniformizing plate.

[0010] Optionally, the diameters of the flow uniformizing holes gradually increase from the inner ring to the outer ring of the flow uniformizing plate.

[0011] Optionally, a plurality of protruding shoulders are circumferentially arranged on the flow uniformizing plate, and a plurality of threaded holes are radially arranged on the protruding shoulders.

[0012] Optionally, the fitting gap between the flow uniformizing plate and the plug cone is 0.4-0.6 mm.

[0013] Optionally, the jet flow holes are circumferentially arranged in two rows along the shell.

[0014] The application provides a liquid nitrogen jet flow system comprising the low-temperature cold air generating device.

[0015] Compared with the prior art, the application has the following beneficial effects: The low-temperature cold air generating device is characterized in that: a shell and a plug cone are arranged to form an annular cavity between the plug cone and the inner wall of the shell; a liquid collecting ring and a jet hole are arranged on the shell to enable liquid nitrogen to enter the annular cavity between the plug cone and the inner wall of the shell under the action of the liquid collecting ring and the jet hole; air is introduced into the shell upstream to make the air branch off when meeting the plug cone, form annular air flow at the position of the jet hole, and meet the liquid nitrogen, so that the liquid nitrogen and the air are rapidly subjected to heat and mass transfer under the entrainment effect in the annular cavity; the low-temperature mixed gas formed by the liquid nitrogen and the air after heat absorption and vaporization into nitrogen gas is uniformly distributed by a flow uniformizing plate and then flows along the outer wall of the plug cone to the inside of the shell downstream of the plug cone for further mixing, thereby forming low-temperature cold air with uniform pressure and temperature.

[0016] The thin-wall shell is provided with a plurality of support rods connected to the shell, which not only meets the installation requirements of the thin-wall shell in the internal space of the shell, facilitates assembly and disassembly, but also ensures the stability of the relative position of the thin-wall shell and the external shell to resist external load and deformation.

[0017] The cross-sectional shape of the thin-wall shell is a streamlined cross-section, and the fluid cross-section can significantly reduce the resistance of the thin-wall shell to fluid flow, thereby reducing the generation of vortexes and further improving the heat exchange efficiency.

[0018] The flow uniformizing plate is an annular flow uniformizing plate provided with a plurality of flow uniformizing holes, which can make the low-temperature mixed gas flow uniformly and ensure the uniformity of distribution, thereby further improving the quality of the low-temperature gas.

[0019] The flow uniformizing holes are staggered from the inner ring to the outer ring of the flow uniformizing plate, which helps to improve the turbulence intensity of the fluid during the flow process, promotes fluid mixing, and reduces the phenomenon of excessively high or low local flow rate.

[0020] The diameter of the flow equalizing hole gradually increases from the inner ring to the outer ring of the flow equalizing plate, so that the fluid can gradually adapt to the change of flow rate when passing through the flow equalizing plate, the gradually increasing flow equalizing hole design reduces the pressure loss caused by sudden change of flow rate, and is adapted to the temperature distribution of the upstream fluid, which helps the smooth transition of the fluid on the flow equalizing plate and improves the mixing effect of liquid nitrogen and air.

[0021] The flow equalizing plate is provided with a plurality of shoulders in the circumferential direction, and the shoulders are provided with threaded holes in the radial direction of the flow equalizing plate, so that the flow equalizing plate can be conveniently installed and fixed in the shell, and the processing difficulty and cost are low.

[0022] The fitting gap between the flow equalizing plate and the plug cone is 0.4-0.6mm, the force transmission path between the flow equalizing plate and the plug cone is cut off, the local stress caused by the inconsistent deformation direction of the plug cone and the flow equalizing plate is reduced, the overall stress level of the device is reduced, and the service life of the device is prolonged.

[0023] The jet flow holes are arranged in two rows in the circumferential direction of the shell, which can more effectively reduce the cooling dead zone on the shell, ensure that the liquid nitrogen flowing out of the jet flow holes can cover the circumferential space inside the shell, and improve the uniformity of the mixing of liquid nitrogen and air.

[0024] A liquid nitrogen jet system comprising the low-temperature cold air generating device. The liquid nitrogen jet system has higher heat exchange efficiency, more compact structure, low energy consumption, fast cooling speed, and wide application prospect in the fields of food processing, material testing, medical equipment cooling and the like. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a shaft side structure diagram of a low-temperature cold air generating device.

[0026] Figure 2 It is a sectional view of a low-temperature cold air generating device.

[0027] Figure 3 It is a front view of a low-temperature cold air generating device.

[0028] Figure 4 It is a left view of a low-temperature cold air generating device.

[0029] Figure 5 It is an overall sectional view of a shell and a liquid collecting ring of a low-temperature cold air generating device.

[0030] Figure 6 It is a partial sectional view of a plug cone of a low-temperature cold air generating device.

[0031] Figure 7A schematic view of a flow uniformizing plate structure of a low-temperature cold air generating device according to Embodiment 1 of the present application.

[0032] Figure 8 A schematic view of an axial side of a flow uniformizing plate structure of a low-temperature cold air generating device according to Embodiment 1 of the present application.

[0033] Figure 9 A front view of a flow uniformizing plate of a low-temperature cold air generating device according to Embodiment 1 of the present application.

[0034] Figure 10 A schematic view of a flow uniformizing plate structure of a low-temperature cold air generating device according to Embodiment 2 of the present application.

[0035] Figure 11 A schematic view of an axial side of a flow uniformizing plate structure of a low-temperature cold air generating device according to Embodiment 2 of the present application.

[0036] Wherein, 100 - shell, 200 - choke cone, 300 - flow uniformizing plate, 110 - air inlet, 120 - liquid nitrogen inlet, 130 - liquid collecting ring, 140 - jet hole, 150 - cold air outlet, 201 - thin-walled shell, 202 - support rod, 310 - base plate, 320 - shoulder, 330 - flow uniformizing hole. DETAILED DESCRIPTION

[0037] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0039] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0040] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0041] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0042] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, if the terms "arrangement", "installation", "connection", "connection" appear, they should be understood in a broad sense, for example, they can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or indirectly connected through an intermediate medium; can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0043] The present application will be further described in detail below in conjunction with specific embodiments, which are an explanation of the present application rather than a limitation.

[0044] Referring to Figures 1 to 4 The present application discloses a low-temperature cold air generating device, comprising a shell 100, the shell 100 is a cylindrical structure, a plug cone 200 is arranged inside the shell 100, the plug cone 200 comprises a thin-walled shell 201, a plurality of support rods 202 are arranged on the thin-walled shell 201, and the support rods 202 are connected with the shell 100; an annular cavity is formed between the plug cone 200 and the inner wall of the shell 100, a plurality of flow uniformizing plates 300 are arranged in the annular cavity, the flow uniformizing plates 300 are annular flow uniformizing plates, a plurality of flow uniformizing holes 330 are arranged on the flow uniformizing plates 300, preferably, the fitting gap between the flow uniformizing plates 300 and the plug cone 200 is 0.4-0.6mm; a liquid collecting ring 130 is circumferentially arranged on the shell 100 upstream of the plug cone 200, and the liquid collecting ring 130 is connected with a liquid nitrogen source; a plurality of jet holes 140 are arranged on the shell 100 corresponding to the liquid collecting ring 130.

[0045] Embodiment 1 Referring to Figures 1 to 5The application discloses a low-temperature cold air generating device, which comprises a shell 100, a plug cone 200 and a plurality of flow uniformizing plates 300. The shell 100 is in a cylindrical structure, one end of which is provided with an air inlet 110, and the other end is provided with a cold air outlet 150; a liquid collecting ring 130 is arranged on the shell 100 in a circumferential direction; a plurality of jet holes 140 are arranged on the shell 100 in a circumferential direction at a position corresponding to the liquid collecting ring 130; the jet holes 140 are arranged in two rows and uniformly arranged on the inner side of the liquid collecting ring 130 in a circumferential direction; preferably, the jet direction of the jet holes 140 is less than 90 degrees to the axial direction of the shell 100, and the jet direction is towards the cold air outlet 150; a liquid nitrogen inlet 120 is arranged on the liquid collecting ring 130, and the liquid nitrogen inlet 120 is connected with a liquid nitrogen source.

[0046] Referring to Figure 6 The plug cone 200 is arranged in the shell 100, and an annular cavity is formed between the plug cone 200 and the inner wall of the shell 100; the plug cone 200 comprises a thin-walled shell 201 and a plurality of supporting rods 202; the cross section of the thin-walled shell 201 is in a streamline shape; the supporting rods 202 are connected with the thin-walled shell 201; and threaded connection holes are arranged on the supporting rods 202 and used for connecting with the shell 100.

[0047] Referring to Figures 7 to 9 The flow uniformizing plate 300 is arranged in the annular cavity formed between the plug cone 200 and the inner wall of the shell 100, is in an annular structure, is sleeved outside the thin-walled shell 201 of the plug cone 200, and has a sleeve gap of 0.4-0.6 mm with the thin-walled shell 201; a plurality of flow uniformizing holes 330 are arranged on the flow uniformizing plate 300; the flow uniformizing holes 330 are circular flow uniformizing holes arranged in a staggered manner from the inner ring to the outer ring of the flow uniformizing plate 300, and the diameters of the flow uniformizing holes 330 gradually increase from the inner ring to the outer ring of the flow uniformizing plate 300; a plurality of shoulders 320 are arranged on the flow uniformizing plate 300 in a circumferential direction; and threaded holes are arranged on the shoulders 320 in a radial direction of the flow uniformizing plate 300.

[0048] Embodiment 2 Referring to Figures 1 to 5 The application discloses a low-temperature cold air generating device, which comprises a shell 100, a plug cone 200 and a plurality of flow uniformizing plates 300; The shell 100 is a cylindrical structure, one end of which is provided with an air inlet 110, the other end is provided with a cold air outlet 150, the shell 100 is provided with a liquid collecting ring 130 in a circumferential direction, and a plurality of jet holes 140 are arranged on the shell 100 corresponding to the position of the liquid collecting ring 130, the jet holes 140 are arranged in two rows and uniformly arranged on the inner side of the liquid collecting ring 130, preferably, the jet direction of the jet hole 140 is less than 90° with the axial direction of the shell 100, and the jet direction is towards the cold air outlet 150, the liquid collecting ring 130 is provided with a liquid nitrogen inlet 120, and the liquid nitrogen inlet 120 is connected with a liquid nitrogen source.

[0049] Referring to Figure 6 , the plug cone 200 is arranged in the interior of the shell 100, and an annular cavity is formed between the plug cone 200 and the inner wall of the shell 100, the plug cone 200 comprises a thin-walled shell 201 and a plurality of supporting rods 202, the cross section of the thin-walled shell 201 is a streamlined cross section, the supporting rod 202 is connected with the thin-walled shell 201, and the supporting rod 202 is provided with a threaded connection hole for connecting with the shell 100.

[0050] Referring to Figure 10 and Figure 11 , the flow uniformizing plate 300 is arranged in the annular cavity formed between the plug cone 200 and the inner wall of the shell 100, is a ring-shaped structure, is sleeved outside the thin-walled shell 201 of the plug cone 200, the sleeve gap between the flow uniformizing plate 300 and the thin-walled shell 201 is 0.4-0.6mm; the flow uniformizing plate 300 comprises a base plate 310, a plurality of shoulders 320 and a plurality of flow uniformizing holes 330, the flow uniformizing holes 330 are arranged on the base plate 310, the flow uniformizing holes 330 are screen-shaped flow uniformizing holes, the shoulders 320 are arranged as four, and are arranged in a circumferential direction along the outer edge of the base plate 310, the shoulders 320 are provided with threaded holes in the radial direction of the flow uniformizing plate 300.

[0051] Example 3 Referring to Figures 1 to 5 , the application provides a low-temperature cold air generating device, comprising: a shell 100, a plug cone 200 and a flow uniformizing plate 300; The shell 100 is a cylindrical structure, and air inlets 110 and cold air outlets 150 are arranged at two ends of the shell 100 respectively, the shell 100 is connected with other equipment through flanges, and sealing gaskets are arranged at the flange connection positions to ensure the sealing performance; a liquid collecting ring 130 is welded downstream close to the air inlets 110, two liquid nitrogen inlets 120 are arranged on the liquid collecting ring 130, the liquid nitrogen inlets 120 are connected with a liquid nitrogen source, and two rows of jet holes 140 are arranged at the connection position between the liquid collecting ring 130 and the shell 100, the jet direction of the jet holes 140 is less than 90° with the axial direction of the shell 100, and the jet holes 140 need to be ensured to be located before the first flow uniforming plate 300; the shell 100 is provided with a convex corresponding to the flow uniforming plate 300 and a convex corresponding to the plug cone 200, the center of the convex is a through hole penetrating through the wall of the cylinder, and the through hole is used for fixing the plug cone 200 and the flow uniforming plate 300 on the shell 100.

[0052] The plug cone 200 and the flow uniforming plate 300 are arranged in the shell 100, the plug cone 200 is fixed on the shell 100 through fastening bolts, and an annular cavity is formed between the outer wall of the plug cone 200 and the inner wall of the shell 100; the flow uniforming plate 300 is provided in two, is sequentially arranged on the plug cone 200, is located in the annular channel, and is fixed on the shell 100 through fastening bolts. Referring to Figure 6 The plug cone 200 includes a thin-walled shell 201 and a cylindrical support rod 202 arranged on the thin-walled shell 201, and the thin-walled shell 201 is streamlined as a whole, so as to reduce the resistance of the upstream airflow and avoid that the upstream airflow is separated before and after the plug cone 200; the welding position between the support rod 202 and the thin-walled shell 201 is transitioned through a reinforcing boss, so as to reduce the local stress at the position, the support rod 202 bears the axial stress of the plug cone 200, the flow uniforming plate 300 bears the radial stress of the plug cone 200, and the plug cone 200 is allowed to move back and forth in the axial direction, on the one hand, the force transmission path is simple and efficient, and is beneficial to release the structural stress and strain caused by temperature difference; on the other hand, the plug cone 200 is beneficial to assembly and sealing, and cost is saved. The cylindrical support rod 202 is provided with a cylindrical step with a certain length at the other end, and a threaded hole is formed in the cylindrical step, so as to fix the plug cone 200 and the shell 100.

[0053] Referring to Figures 7 to 11 The flow uniforming plate 300 is a hole plate structure, and the flow uniforming plate 300 is provided in two, includes a base plate 310 and flow uniforming holes 330 formed in the base plate 310. Four threaded- hole shoulders 320 are arranged at the edge region of the base plate 310, the included angle between two adjacent threaded-hole shoulders 320 is 90°, and the center of each threaded-hole shoulder 320 is a threaded hole, which is used for fixing the flow uniforming plate 300 and the shell 100.

[0054] Referring to Figures 7 to 9One of the flow uniformity holes 330 of the flow uniformity plate 300 is a plurality of circular holes with different sizes, and the diameter of the flow uniformity hole 330 gradually increases from the inner ring to the outer ring of the flow uniformity plate 300.

[0055] Referring to Figure 10 and Figure 11 The flow uniformity hole 330 of the other flow uniformity plate 300 is a screen structure, and a plurality of fan-shaped flow uniformity holes 330 are formed on the flow uniformity substrate 310 by intersecting steel wires horizontally and vertically. The flow uniformity plate 300 of this structure has higher porosity and smaller flow resistance, which can be reasonably selected according to actual conditions.

[0056] In use, liquid nitrogen enters the liquid collection ring 130 through the two liquid nitrogen inlets 120, and then enters the annular cavity formed by the plug cone 200 and the shell 100 through the two rows of jet holes 140. At the same time, air enters the shell 100 through the air inlet 110, and flows into the annular cavity after encountering the plug cone 200, and meets the liquid nitrogen ejected from the jet hole 140. The liquid nitrogen and the air are rapidly heat and mass transferred in the annular cavity, and are vaporized into nitrogen gas after absorbing heat, and form a low-temperature mixed gas with the air. The low-temperature mixed gas flows through the flow uniformity plate 300, and is further mixed after the flow uniformity plate 300, and finally forms a low-temperature cold air with uniform pressure and temperature, which flows out from the cold air outlet 150.

[0057] The present application provides a liquid nitrogen jet system comprising the above-mentioned low-temperature cold air generating device. The liquid nitrogen jet system has higher heat transfer efficiency, more compact structure, and low energy consumption, fast cooling speed, and wide application prospect in the fields of food processing, material testing, medical equipment cooling, etc.

[0058] In summary, the present application provides a low-temperature cold air generating device and a liquid nitrogen jet system, which is designed to spray from the side wall, so that the liquid nitrogen does not directly or indirectly contact with air before entering the device during the whole low-temperature cold air generating process. This effectively avoids the problems of insufficient latent heat utilization and low heat transfer efficiency caused by heat exchange with air before the jet hole of the traditional liquid nitrogen jet cooling device, thereby being more conducive to the adjustment of cold air temperature, and being more easily to realize the miniaturization requirement of the device and improve the application breadth of the product.

[0059] The above-mentioned is only the preferred embodiment of the present application, and does not limit the technical solutions of the present application in any way. Those skilled in the art should understand that the technical solutions can be modified and replaced in several simple ways without departing from the spirit and principles of the present application, and these modifications and replacements also belong to the protection scope covered by the claims.

Claims

1. A low-temperature cold air generating device, characterized in that: The invention comprises a shell (100), wherein the shell (100) is a cylindrical structure, and a blocking cone (200) is provided inside the shell (100); an annular cavity is formed between the blocking cone (200) and the inner wall of the shell (100), and a plurality of flow equalizing plates (300) are provided in the annular cavity; a liquid collecting ring (130) is circumferentially provided on the shell (100) upstream of the blocking cone (200), and the liquid collecting ring (130) is connected to a liquid nitrogen source; and a plurality of jet holes (140) are provided on the shell (100) corresponding to the liquid collecting ring (130).

2. The low-temperature cold air generating device according to claim 1, characterized in that: The blocking cone (200) comprises a thin-walled shell (201), a plurality of support rods (202) are provided on the thin-walled shell (201), and the support rods (202) are connected to the shell (100).

3. The low-temperature cold air generating device according to claim 2, characterized in that: The cross-sectional shape of the thin-walled shell (201) is a streamlined cross-sectional shape.

4. The low-temperature cold air generating device according to claim 1, characterized in that: The flow balancing plate (300) is an annular flow balancing plate, and a plurality of flow balancing holes (330) are provided on the flow balancing plate (300).

5. The low-temperature cold air generating device according to claim 4, characterized in that: The flow balancing holes (330) are arranged in a staggered manner from the inner ring to the outer ring of the flow balancing plate (300).

6. The low-temperature cold air generating device according to claim 5, characterized in that: The diameter of the flow balancing holes (330) gradually increases from the inner ring to the outer ring of the flow balancing plate (300).

7. The low-temperature cold air generating device according to claim 1, characterized in that: A plurality of bosses (320) are provided on the flow balancing plate (300) along the circumferential direction, and threaded holes are provided on the bosses (320) along the radial direction of the flow balancing plate (300).

8. The low-temperature cold air generating device according to claim 1, characterized in that: The fitting gap between the flow balancing plate (300) and the blocking cone (200) is 0.4-0.6 mm.

9. The low-temperature cold air generating device according to claim 1, characterized in that: The jet holes (140) are arranged in two rows along the circumferential direction of the shell (100).

10. A liquid nitrogen jet system, characterized in that: It comprises the low-temperature cold air generating device according to any one of claims 1 to 9.

Images