Nozzle structure for jetting liquid lithium target

Abstract

The utility model relates to the technical field of nozzle structures, in particular to a nozzle structure for jetting a liquid lithium target. According to the technical scheme, the nozzle structure comprises a liquid inlet pipe and a flow trace adjusting valve connected to the output end of the liquid inlet pipe, the bottom end of the flow trace adjusting valve is connected with a second-stage Laval nozzle in a sealed mode, the tail end of the second-stage Laval nozzle is connected with a concave back wall, and a liquid collecting groove is formed in the lower portion of the concave back wall; the flow trace adjusting valve comprises a diameter expanding section and a restraining section, the liquid inlet pipe is connected with the diameter expanding section, and the restraining section is internally composed of a plurality of sets of densely-arranged holes. The nozzle structure provided by the utility model can continuously and stably form a jet liquid lithium film, can form a stable liquid lithium film on a concave back wall, and meets the formation requirement of a liquid lithium target.

Description

Technical Field

[0001] This utility model relates to the field of nozzle structure technology, and in particular to a nozzle structure for jet liquid lithium target. Background Technology

[0002] According to recommendations from the International Atomic Energy Agency, the thermal neutron flux density required for BNCT therapy must be greater than 5 × 10⁸ n·cm². -2 ·s -1 However, current accelerator-based neutron generators struggle to achieve this goal. Because the Li(p,n) reaction threshold is low and neutron yield is high below 3.5 MeV, lithium targets are typically used as the target material for neutron generators. Although the reaction cross-section of a proton incident on a lithium target is relatively large, the proportion of protons reacting is still very small, with the vast majority remaining in the target material and forming high-energy deposition. Furthermore, due to lithium's low melting point, it easily melts and evaporates when bombarded by a proton beam. Utilizing high-speed flowing liquid lithium as the target material becomes an effective way to remove high heat loads.

[0003] To efficiently remove the tens of MW / m³ generated during proton beam targeting, liquid lithium targets are needed. 2 The heat load requires a high flow rate. Liquid lithium targets are typically driven by electromagnetic pumps to form a stable liquid film on a concave back wall. However, achieving a flow rate of tens of meters per second for liquid lithium is difficult, placing high demands on the driving capability of the electromagnetic pump. Therefore, it is necessary to design a nozzle structure in the liquid lithium circuit to achieve a flow rate of tens of meters per second to enter the jet state. Simultaneously, the liquid lithium circuit requires components such as valves, electromagnetic pumps, and flow meters, and may contain structures like bends. These components and structures all affect the flowability of the liquid lithium, leading to the inability to form a stable liquid lithium film on the concave back wall. Therefore, a component is needed to regulate the flow path of the liquid lithium before it flows into the nozzle, ensuring a stable flow state. Thus, this application proposes a nozzle structure for jetting liquid lithium targets. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the background technology by proposing a nozzle structure for jet liquid lithium targets.

[0005] The technical solution of this utility model is: a nozzle structure for a jet liquid lithium target, the nozzle structure including a liquid inlet pipe and a flow path regulating valve connected to the output end of the liquid inlet pipe, the bottom end of the flow path regulating valve is sealed with a secondary Laval nozzle, the end of the secondary Laval nozzle is connected to a concave back wall, and a liquid collection groove is provided below the concave back wall.

[0006] The flow regulating valve includes an expansion section and a constraint section. The inlet pipe is connected to the expansion section, and the constraint section consists of multiple sets of densely arranged holes.

[0007] Optionally, the nozzle structure is used to accelerate liquid lithium to a jet state and then form a stable jet liquid lithium film on the concave back wall.

[0008] Optionally, the inner diameter of the expanded section is 2-3 times that of the inlet pipe.

[0009] Optionally, the upper end of the secondary Laval nozzle is connected to the end of the flow path regulating valve and has the same inner diameter;

[0010] The secondary Laval nozzle includes two contraction sections: a circular contraction section and a radial contraction section. The internal transitions between the circular and radial contraction sections are smooth and without sharp edges.

[0011] Optionally, the end of the radially contracting section is a rectangular structure, which is connected to the upper end of the concave back wall along the tangent direction of the concave back wall.

[0012] Optionally, the flow regulating valve, the secondary Laval nozzle, the concave back wall, and the liquid collection tank are all made of low-activation, lithium-corrosion-resistant RAFM steel.

[0013] Optionally, heating wires are wound around the outer walls of both the flow regulating valve and the secondary Laval nozzle to control the temperature of the liquid lithium and ensure its fluidity and wettability.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects:

[0015] This invention aims to overcome technical difficulties under actual working conditions, improve the feasibility of the technology, and provide a nozzle structure that can accelerate the entry of liquid lithium into the jet state and form a stable liquid lithium film. This design can not only effectively remove the disturbances caused by the pipeline structure and circuit components to the liquid lithium flow, but also accelerate the entry of liquid lithium into the jet state to form a stable liquid lithium film. It provides effective technical support for the design of liquid lithium targets.

[0016] Furthermore, by using a two-stage heating wire, which is wound around the flow regulating valve and the secondary Laval nozzle respectively, the liquid lithium is ensured to have good fluidity and wettability.

[0017] In summary, the nozzle structure proposed in this invention can continuously and stably form a jet of liquid lithium film, and can form a stable liquid lithium film on the concave back wall, thus meeting the requirements for the formation of a liquid lithium target. Attached Figure Description

[0018] Figure 1 A schematic diagram of the vacuum target chamber of this utility model is provided;

[0019] Figure 2 This is a schematic diagram of the flow path regulating valve in this utility model;

[0020] Figure 3 for Figure 2 A schematic diagram of the cross-sectional structure;

[0021] Figure 4 This is a schematic diagram of a two-stage Laval nozzle;

[0022] Figure 5 for Figure 1 A frontal view of the cross-section.

[0023] Figure label:

[0024] 1. Liquid inlet pipe;

[0025] 2. Heating wire;

[0026] 3. Flow path regulating valve; 31. Expanding section; 32. Constraint section;

[0027] 4. Two-stage Laval nozzle; 41. Circular contraction section; 42. Radial contraction section;

[0028] 5. Recessed back wall;

[0029] 6. Liquid collection tank. Detailed Implementation

[0030] The technical solutions of this disclosure will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments.

[0031] The components of the embodiments of this disclosure, which are typically described and shown in the accompanying drawings, can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of embodiments of this disclosure provided in the drawings is not intended to limit the scope of the claimed disclosure, but merely to illustrate selected embodiments of the disclosure.

[0032] Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this disclosure.

[0033] In the description of this disclosure, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0034] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure based on the specific circumstances.

[0035] Example

[0036] like Figure 1 As shown, this utility model proposes a nozzle structure for a jet liquid lithium target. The nozzle structure includes an inlet pipe 1 and a flow path regulating valve 3 connected to the output end of the inlet pipe 1. The nozzle structure is used to accelerate liquid lithium to a jet state and form a stable jet liquid lithium film on the concave back wall 5. The bottom end of the flow path regulating valve 3 is sealed with a secondary Laval nozzle 4. The upper end of the secondary Laval nozzle 4 is connected to the end of the flow path regulating valve 3 and has the same inner diameter. The secondary Laval nozzle 4 includes two contraction sections: a circular contraction section 41 and a radial contraction section 42. The two parts can be freely combined according to actual usage requirements to adapt to a wider range of usage scenarios. The circular contraction section 41 and the radial contraction section 42 have smooth transitions without sharp corners. The secondary Laval nozzle 4 can accelerate liquid lithium with a speed of 0.3-1.5 m / s to 10-40 m / s, but too high a speed will result in the inability to form a stable liquid film. The optimal range is 15-25 m / s. The optimal thickness for the secondary Laval nozzle 4 is between 1.5mm and 3.5mm, and the nozzle width must not exceed the width of the concave backwall 5; for BNCT applications, the nozzle width should be between 30mm and 80mm; Figure 4 and Figure 5 As shown, the end of the secondary Laval nozzle 4 is connected to the concave back wall 5. The end of the radially contracting section 42 is a rectangular structure, connected to the upper end of the concave back wall 5 along the tangential direction. The jet lithium film is generated by liquid lithium through the secondary Laval nozzle 4 on the low-activation steel concave back wall 5, and its flow velocity can reach 15 m / s. The area and thickness of the liquid lithium film can be set according to the proton beam and neutron parameters. For example, for 200℃, 2 mm thick, and an area of ​​approximately 25 cm²... 2 Liquid lithium thin film, at 10MW / m 2 The temperature rise under heat flux irradiation ranges from 20-35℃, effectively preventing large-scale evaporation of liquid lithium. Under these parameters, the liquid lithium target can withstand a maximum heat flux density of 30MW / m³. 2 Below the concave back wall 5, there is a liquid collection tank 6, which is an inverted C-shaped tank.

[0037] like Figure 2 and Figure 3As shown, the flow regulating valve 3 includes an expanding section 31 and a constraining section 32. The inlet pipe 1 is connected to the expanding section 31, and the diameter of the expanding section 31 should be one to two times the width of the secondary Laval nozzle 4. The inner diameter of the expanding section 31 is 2 to 3 times that of the inlet pipe 1. The constraining section 32 consists of multiple sets of densely arranged holes, which are round or square holes with a diameter of 1-2 mm. The holes are very dense to ensure good constraining ability while avoiding slow liquid lithium flow. The flow regulating valve 3, the secondary Laval nozzle 4, the concave back wall 5, and the liquid collection tank 6 are all made of low-activation, lithium-corrosion-resistant RAFM steel. Heating wires 2 are wound around the outer walls of the flow regulating valve 3 and the secondary Laval nozzle 4 to control the temperature of the liquid lithium and ensure its fluidity and wettability.

[0038] In this embodiment, liquid lithium is transported through inlet pipe 1, which has various bends and valves in its inner wall. Liquid lithium enters the flow regulating valve 3 in a turbulent flow condition. The constraint section 32 is set to ensure good constraint while avoiding slow liquid lithium flow. The jet lithium film is generated by liquid lithium through a two-stage Laval nozzle 4 on the low-activation steel concave back wall 5.

[0039] The above specific embodiments are merely optional embodiments of this utility model. Based on the technical solution of this utility model and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A nozzle structure for jet liquid lithium target, characterized in that: The nozzle structure includes an inlet pipe (1) and a flow path regulating valve (3) connected to the output end of the inlet pipe (1). The bottom end of the flow path regulating valve (3) is sealed with a secondary Laval nozzle (4). The end of the secondary Laval nozzle (4) is connected to a concave back wall (5). A liquid collection groove (6) is provided below the concave back wall (5). The flow regulating valve (3) includes an expansion section (31) and a constraint section (32). The inlet pipe (1) is connected to the expansion section (31), and the constraint section (32) is composed of multiple sets of densely arranged holes.

2. The nozzle structure for a jet liquid lithium target according to claim 1, characterized in that, The nozzle structure is used to accelerate liquid lithium to a jet state and form a stable jet liquid lithium film on the concave back wall (5).

3. The nozzle structure for a jet liquid lithium target according to claim 1, characterized in that, The inner diameter of the expanded section (31) is 2-3 times that of the inlet pipe (1).

4. The nozzle structure for a jet liquid lithium target according to claim 1, characterized in that, The upper end of the secondary Laval nozzle (4) is connected to the end of the flow path regulating valve (3) and has the same inner diameter; The secondary Laval nozzle (4) includes two contraction sections: a circular contraction section (41) and a radial contraction section (42). The circular contraction section (41) and the radial contraction section (42) have a smooth transition inside and no sharp corners.

5. A nozzle structure for a jet liquid lithium target according to claim 4, characterized in that, The end of the radial contraction section (42) is a rectangular structure, which is connected to the upper end of the concave back wall (5) along the tangent direction of the concave back wall (5).

6. The nozzle structure for a jet liquid lithium target according to claim 1, characterized in that, The flow regulating valve (3), the secondary Laval nozzle (4), the concave back wall (5), and the liquid collection tank (6) are all made of low-activation, lithium-corrosion-resistant RAFM steel.

7. A nozzle structure for a jet liquid lithium target according to claim 1, characterized in that, The outer walls of the flow regulating valve (3) and the secondary Laval nozzle (4) are both wrapped with heating wires (2) to control the temperature of the liquid lithium and ensure its fluidity and wettability.

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