A device and method for testing the content of non-condensable gas in a high-temperature heat pipe

Abstract

This invention belongs to the field of high-temperature heat pipe manufacturing and performance testing technology, specifically relating to a device and method for testing the content of non-condensable gases inside a high-temperature heat pipe. The invention includes an ionization gauge, a resistance gauge, a high-vacuum shut-off valve, a charging / discharging valve, a heating wire, a stainless steel tube, a cooling water jacket, and a T-junction. The stainless steel tube is inserted from the center of the cooling water jacket, and the heating wire is wound around the outside of the upper part of the stainless steel tube, forming a heating section. The upper part of the stainless steel tube in the heating section has a T-junction structure; the second horizontal port is equipped with a charging / discharging valve, and the third vertical port is equipped with a high-vacuum shut-off valve. The top of the stainless steel tube is connected to both the ionization gauge and the resistance gauge. The lower part of the stainless steel tube in the cooling water jacket is connected to the T-junction. This invention enables real-time monitoring of the internal pressure of the high-temperature heat pipe during filling, and can simultaneously perform vacuum degree and non-condensable gas content measurement, filling, and other operations, ensuring that the hot-filling is completed with quality.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature heat pipe manufacturing and performance testing technology, specifically relating to a device and method for testing the content of non-condensable gases inside a high-temperature heat pipe. Background Technology

[0002] Heat pipes are heat transfer elements that rely on the phase change of their internal working fluid to transfer heat. They are known as thermal superconductors, capable of transferring large amounts of heat over long distances through a very small cross-sectional area without the need for external power. High-temperature heat pipes, in particular, are characterized by high operating temperatures and excellent heat transfer performance, making them valuable in applications such as solid-state reactors and thermal protection for supersonic vehicles.

[0003] The performance of the heat pipe itself is one of the key factors affecting the overall system's operational capability and stability. With ongoing performance experiments on high-temperature alkali metal heat pipes both domestically and internationally, serious phenomena such as performance degradation and even failure have been observed, indicating that the stability of current high-temperature alkali metal heat pipes has not yet reached ideal standards. In fact, in existing high-temperature alkali metal heat pipe tests, most heat pipes exhibit a "black zone" at the top where the operating temperature cannot be reached. The inability of the heat pipe's vapor working fluid to enter this "black zone" causes the top portion to fail, significantly impacting the heat pipe's heat transfer capacity and posing a significant threat to the entire heat transfer system. The primary cause of the "black zone" is the presence of non-condensable gases inside the heat pipe. The working fluids of high-temperature alkali metal heat pipes, such as sodium and potassium, have low saturated vapor pressures, generally much lower than standard atmospheric pressure within the operating temperature range. The presence of non-condensable gases obstructs the top of the heat pipe, preventing the low-pressure vapor working fluid from flowing to the top, thus creating a black zone and reducing the heat transfer area. Therefore, in order to improve the performance of heat pipes and enhance their operational stability and lifespan, it is necessary to study and analyze the causes of the generation and accumulation of non-condensable gases in high-temperature alkali metal heat pipes.

[0004] In view of this, the present invention proposes a device and method for testing the content of non-condensable gases inside a high-temperature heat pipe, accurately measuring the content of non-condensable gases inside the heat pipe, understanding its variation law, and providing a means for heat pipe manufacturing. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a device and method for testing the content of non-condensable gases inside a high-temperature heat pipe, which can realize real-time monitoring of the internal pressure during the filling of the high-temperature heat pipe, and can simultaneously realize operations such as vacuum degree and non-condensable gas content measurement and filling, ensuring that the hot filling is completed with quality.

[0006] The technical solution adopted in this invention is as follows: A device for testing the content of non-condensable gases inside a high-temperature heat pipe includes an ionization gauge tube, a resistance gauge tube, a high-vacuum shut-off valve, a charging / discharging valve, a heating wire, a stainless steel tube, a cooling water jacket, and a tee pipe. The stainless steel tube is inserted from the center of the cooling water jacket, and the heating wire is wound around the outside of the stainless steel tube at the upper end of the cooling water jacket to form a heating section. The stainless steel tube at the upper end of the heating section has a tee structure, with a charging / discharging valve on the second horizontal port and a high-vacuum shut-off valve on the third vertical port. The ionization gauge tube and the resistance gauge tube are respectively connected to the top of the stainless steel tube. The stainless steel tube at the lower end of the cooling water jacket is connected to the tee pipe.

[0007] The ends of the ionization gauge and the resistance gauge are respectively connected to the corresponding installation and measurement and control accessories.

[0008] The second end of the tee is provided with a flange, and the third end of the tee is connected to the alkali metal heat pipe by welding.

[0009] The second port of the three-way pipe is at a certain angle to the horizontal.

[0010] The flange is connected to the heat pipe filling device, and is sealed after filling is completed.

[0011] The ionization gauge is used to accurately measure the gas pressure in the top chamber of the heat pipe under high vacuum, and the resistance gauge is used to accurately measure the gas pressure in the top chamber of the heat pipe under low vacuum.

[0012] The cooling water jacket has internal channels, which, from the inside out, are: a central stainless steel pipe clearance channel, an annular air gap, and the outermost cooling water flow channel.

[0013] The central stainless steel tube has three slots for inserting thermocouples to measure the wall temperature; the upper end of the annular air gap is provided with two symmetrically arranged baffles to separate the air intake, and there are two air inlets at the upper end; the water inlets of the cooling water jacket are located on both sides.

[0014] The stainless steel pipe is interference-fitted with the center hole of the cooling water jacket and is designed with a fixing clamping mechanism.

[0015] A testing method for a device for testing the content of non-condensable gases inside a heat pipe includes the following steps: S1. The pressure of non-condensable gas inside the stainless steel tube is displayed through the ionization gauge and the resistance gauge. S2. Open the charging / discharging valve to evacuate the gas. Observe the vacuum values ​​measured by the ionization gauge and the resistance gauge to determine the change in the pressure of the non-condensable gas. S3. Observe the changes in vacuum level, noting the values ​​of the resistance gauge at low vacuum and the ionization gauge at high vacuum to determine the vacuum range. During the evacuation process, the pressure inside the heat pipe gradually decreases from atmospheric pressure. Within the vacuum range from atmospheric pressure to 0.1 Pa, use the resistance gauge to measure the internal vacuum level; once the pressure drops below 0.1 Pa, use the ionization gauge to measure the internal vacuum level. S4, The target value needs to be reduced to 10. -5 Pa is even lower than the appropriate value. Close the charging / discharging valve, open the heat pipe filling device, complete the filling and weld the seal. Monitor the pressure changes of the ionization gauge and the resistance gauge at this time. Finally, let it stand for a certain period of time and observe the final pressure change. S5. By calculating the pressure balance, the vacuum degree is measured. The content of the remaining non-condensable gas is evaluated based on the difference between the vacuum degree when the heat pipe filling device is evacuated and the final pressure value observed by the ionization gauge and the resistance gauge after standing for a certain period of time. This evaluates the manufacturing quality of the heat pipe.

[0016] The beneficial effects of this invention are: (1) The present invention provides a device and method for testing the content of non-condensable gases inside a high-temperature heat pipe, which realizes the measurement function of internal pressure and non-condensable gases during the heat pipe filling process, thereby monitoring the vacuum degree of the heat pipe in real time. It can accurately determine whether the heat pipe filling quality meets the standard. Therefore, it can be used for testing the content of non-condensable gases during the heat pipe filling process under various working conditions. It has the advantages of innovation and complete structure.

[0017] (2) The present invention provides a device and method for testing the content of non-condensable gas inside a high-temperature heat pipe. During the filling process, the volume pressure of the non-condensable gas inside is measured, which solves the problem that the existing filling structure does not have the function of real-time monitoring of the internal non-condensable gas and pressure. It can be widely used in the manufacturing and use environment of heat pipes. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in describing the embodiments of the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments recorded in the present invention. Those skilled in the art can derive other drawings from the following drawings without any creative effort.

[0019] Figure 1 This invention provides a schematic diagram of a device for testing the content of non-condensable gases inside a high-temperature heat pipe.

[0020] In the diagram: 1-Ionization gauge tube, 2-Resistance gauge tube, 3-High vacuum shut-off valve, 4-Inflation / Depression valve, 5-Heating wire, 6-Stainless steel tube, 7-Cooling water jacket, 8-Tee pipe, 9-Flange.

[0021] Figure 2 This is a top view of the cooling water jacket. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., refer to the orientation or positional relationship shown in the accompanying drawings, and are used only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 a connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] like Figure 1 As shown, the present invention provides a high-temperature heat pipe internal non-condensable gas content testing device, including an ionization gauge tube 1, a resistance gauge tube 2, a high vacuum shut-off valve 3, a charging / discharging valve 4, a heating wire 5, a stainless steel tube 6, a cooling water jacket 7, a tee pipe 8, and a flange 9. The stainless steel tube 6 is inserted from the center of the cooling water jacket 7. The heating wire 5 is wound around the outside of the stainless steel tube 6 located at the upper end of the cooling water jacket 7 to form a heating section. The lower end of the heating section is 15mm away from the upper end face of the cooling water jacket 7. Under experimental conditions, the working temperature of the heating section is about 200℃. The stainless steel pipe 6 at the upper end of the heating section has a three-way structure. The second horizontal port is equipped with a charging / discharging valve 4, and the third vertical port is equipped with a high vacuum shut-off valve 3. The working temperature of the shut-off valve is not higher than 200℃. The top of the stainless steel tube 6 is respectively connected to the ionization gauge tube 1 and the resistance gauge tube 2; The ends of the ionization gauge tube 1 and the resistance gauge tube 2 are respectively connected to the corresponding installation and measurement and control accessories; A stainless steel pipe 6 located at the lower end of the cooling water jacket 7 is connected to a three-way pipe 8. The second end of the three-way pipe 8 is provided with a flange 9, which is connected to the heat pipe filling device. After the filling is completed, the pipe is sealed. The second channel forms a certain angle with the horizontal, preferably 30°.

[0026] The third port of the three-way pipe 8 is connected to the alkali metal heat pipe by welding. Under the final experimental conditions, the working fluid inside the pipe is sodium vapor (around 600°C), and the pipe wall temperature can reach 700°C.

[0027] The high-temperature alkali metal heat pipe can also be a medium-temperature water heat pipe, a low-temperature working fluid heat pipe, etc.

[0028] The vertical section of the tee pipe 8 should be as short as possible, and the bevel should not contact the cooling water jacket 7; the length of the bevel section should be at least 60mm, measured from the horizontal position corresponding to the outer edge of the cooling water jacket 7.

[0029] The ionization gauge 1 is used to accurately measure the gas pressure in the top chamber of a heat pipe under high vacuum.

[0030] Resistance gauge 2 is used to accurately measure the gas pressure in the top chamber of a heat pipe under low vacuum conditions.

[0031] The high vacuum shut-off valve 3 is used to cut off and open the gas in the top chamber of the heat pipe from other devices.

[0032] Stainless steel tube 6 is used for the flow of gas and working fluid in the top chamber of the heat pipe.

[0033] The cooling water jacket 7 is used to cool the gas in the top chamber inside the heat pipe.

[0034] like Figure 2 As shown, the cooling water jacket 7 has an internal channel, which consists of the following from the inside out: a central stainless steel pipe 6 clearance fit channel, an annular air gap, and the outermost cooling water flow channel.

[0035] The cooling water jacket adopts a multi-layer sleeve design, such as Figure 2 As shown, from the inside out, the structure consists of: a central stainless steel tube with a Φ8×1 clearance fit channel, a 1mm thick annular air gap, and an outermost 2mm thick cooling water channel. The central stainless steel tube clearance fit channel has three slots, each 2mm wide and approximately 1.2mm deep, for inserting thermocouples to measure wall temperature. These three slots are arranged in a 120° equidistant array. Two symmetrically arranged 20mm long baffles are located at the upper end of the annular air gap to separate the air intake; two Φ×1 air inlets are also located at the upper end. The cooling water jacket inlets are located on both sides, with a Φ8×1 inlet size.

[0036] The stainless steel tube 6 is interference-fitted with the center hole of the cooling water jacket 7 and is designed with a fixing clamping mechanism to prevent relative sliding between the stainless steel tube 6 and the cooling water jacket 7.

[0037] According to the present invention, unless otherwise specified, the pipes are uniformly Φ8×1 SS316 stainless steel pipes.

[0038] This invention provides a method for testing the content of non-condensable gases inside a high-temperature heat pipe, comprising the following steps: S1. The pressure of non-condensable gas inside the stainless steel tube 6 is displayed through the ionization gauge tube 1 and the resistance gauge tube 2. S2. Open the charging / discharging valve 4 to evacuate the vacuum. By observing the vacuum values ​​measured by the ionization gauge tube 1 and the resistance gauge tube 2, determine the change in the pressure of the non-condensable gas. S3. Observe the change in vacuum level, the value of resistance gauge 2 at low vacuum level, and the value of ionization gauge 1 at high vacuum level to determine the vacuum level range. During the evacuation process, the pressure inside the heat pipe gradually decreases from atmospheric pressure. Within the vacuum range from atmospheric pressure to 0.1 Pa, use resistance gauge 2 to measure the internal vacuum level; when the pressure drops below 0.1 Pa, use ionization gauge 1 to measure the internal vacuum level. S4. The target value needs to be reduced to 10-5 Pa or even lower until a suitable value is reached. Close the charging / discharging valve 4, turn on the heat pipe filling device, complete the filling and weld the seal. Monitor the pressure changes of the ionization gauge 1 and the resistance gauge 2 at this time. Finally, let it stand for a certain period of time and observe the final pressure change. S5. By calculating the pressure balance, the vacuum degree is measured. The content of the remaining non-condensable gas is evaluated based on the difference between the vacuum degree when the heat pipe filling device is evacuated and the final pressure value observed by the ionization gauge tube 1 and the resistance gauge tube 2 after standing for a certain period of time. The manufacturing quality of the heat pipe is then evaluated.

[0039] This invention overcomes the problem that the internal vacuum degree cannot be measured during the existing heat pipe filling process, and can simultaneously realize the measurement of vacuum degree and non-condensable gas content, filling and other operations.

[0040] While those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention, the embodiments should be considered illustrative and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and therefore all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0041] Furthermore, it should be understood that although the present invention is described according to embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A device for testing the content of non-condensable gases inside a high-temperature heat pipe, characterized in that, The system includes an ionization gauge tube (1), a resistance gauge tube (2), a high vacuum shut-off valve (3), a charge / discharge valve (4), a heating wire (5), a stainless steel tube (6), a cooling water jacket (7), and a three-way pipe (8). The stainless steel tube (6) is inserted from the center of the cooling water jacket (7). The heating wire (5) is wound around the outside of the stainless steel tube (6) at the upper end of the cooling water jacket (7) to form a heating section. The stainless steel tube (6) at the upper end of the heating section has a three-way structure. The second horizontal port is equipped with a charge / discharge valve (4), and the third vertical port is equipped with a high vacuum shut-off valve (3). The top of the stainless steel tube (6) is connected to the ionization gauge tube (1) and the resistance gauge tube (2). The stainless steel tube (6) at the lower end of the cooling water jacket (7) is connected to the three-way pipe (8).

2. The device for testing the content of non-condensable gases inside a high-temperature heat pipe according to claim 1, characterized in that, The ionization gauge (1) and the resistance gauge (2) are respectively connected to corresponding installation and measurement and control accessories.

3. The device for testing the content of non-condensable gases inside a high-temperature heat pipe according to claim 2, characterized in that, The second end of the three-way pipe (8) is provided with a flange (9), and the third end of the three-way pipe (8) is connected to the alkali metal heat pipe by welding.

4. The device for testing the content of non-condensable gases inside a high-temperature heat pipe according to claim 3, characterized in that, The second port of the three-way pipe (8) is at a certain angle to the horizontal.

5. The device for testing the content of non-condensable gases inside a high-temperature heat pipe according to claim 4, characterized in that, The flange (9) is connected to the heat pipe filling device, and is sealed after filling is completed.

6. The device for testing the content of non-condensable gases inside a high-temperature heat pipe according to claim 5, characterized in that, The ionization gauge (1) is used to accurately measure the gas pressure in the top chamber of the heat pipe under high vacuum, and the resistance gauge (2) is used to accurately measure the gas pressure in the top chamber of the heat pipe under low vacuum.

7. The device for testing the content of non-condensable gases inside a high-temperature heat pipe according to claim 6, characterized in that, The cooling water jacket (7) has internal channels, which are: a central stainless steel pipe gap fit channel, an annular air gap and the outermost cooling water flow channel from the inside to the outside.

8. The device for testing the content of non-condensable gases inside a high-temperature heat pipe according to claim 7, characterized in that, The central stainless steel tube has three slots for inserting thermocouples to measure the wall temperature; the upper end of the annular air gap is provided with two symmetrically arranged baffles to separate the air intake, and there are two air inlets at the upper end; the water inlets of the cooling water jacket are located on both sides.

9. The device for testing the content of non-condensable gases inside a high-temperature heat pipe according to claim 8, characterized in that, The stainless steel pipe (6) is interference-fitted with the center hole of the cooling water jacket (7) and is designed with a fixing clamping mechanism.

10. A testing method based on the non-condensable gas content testing device inside a heat pipe according to claim 9, characterized in that, Includes the following steps: S1. The pressure of non-condensable gas inside the stainless steel tube (6) is displayed by the ionization gauge (1) and the resistance gauge (2); S2. Open the charging / discharging valve (4) to evacuate the vacuum. By observing the vacuum values ​​measured by the ionization gauge (1) and the resistance gauge (2), determine the change in the pressure of the non-condensable gas. S3. Observe the change in vacuum level, the value of the resistance gauge (2) at low vacuum level and the value of the ionization gauge (1) at high vacuum level to determine the vacuum level range. During the evacuation process, the pressure inside the heat pipe gradually decreases from atmospheric pressure. Within the vacuum range from atmospheric pressure to 0.1 Pa, the resistance gauge (2) is used to measure the internal vacuum level; when the pressure drops below 0.1 Pa, the ionization gauge (1) is used to measure the internal vacuum level. S4, The target value needs to be reduced to 10. -5 Pa is even lower than the appropriate value. Close the charging / discharging valve (4), turn on the heat pipe filling device, complete the filling and weld the seal, monitor the pressure change of the ionization gauge (1) and the resistance gauge (2) at this time, and finally let it stand for a certain time to observe the final pressure change. S5. Measure the vacuum degree through pressure balance calculation. Evaluate the content of remaining non-condensable gas and assess the heat pipe manufacturing quality based on the vacuum degree when the heat pipe filling device is evacuated and the difference between the final pressure value observed by the ionization gauge (1) and the resistance gauge (2) after standing for a certain period of time.

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