Liquid injection system of liquid storage expansion tank, heat dissipation system of liquid injection system, design method and liquid injection method

Abstract

The invention discloses a liquid injection system of a liquid storage expansion tank, a heat dissipation system of the liquid injection system, a design method and a liquid injection method. The liquid injection system comprises a liquid storage expansion tank, the interior of a tank body of the liquid storage expansion tank is divided into a left cabin and a right cabin, a one-way valve is communicated between the left cabin and the right cabin, and a liquid injection port, a two-way liquid cooling connector I, a liquid discharge port and a two-way liquid cooling connector II are arranged on the tank body. The heat dissipation system comprises a circulating pump, a liquid cooling plate assembly and an air cooling heat exchanger assembly, and further comprises the liquid injection system. The design method aims at the liquid injection system and comprises the steps that refrigerant temperature difference volume change is calculated; carrying out model selection and design on the metal corrugated pipe; and calculating the pressure borne by the metal corrugated pipe and the pressure intensity. The liquid injection method adopts the liquid injection system and comprises forward liquid injection and reverse liquid injection. The beneficial effects of the invention are that miniaturization and high reliability are considered; the reasonable model selection design of the liquid storage expansion tank is realized; a cross reverse liquid injection method is designed, and sufficient exhaust is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic equipment heat dissipation, and particularly relates to a liquid storage expansion tank liquid injection system, a heat dissipation system thereof, a design method and a liquid injection method. BACKGROUND

[0002] An integrated liquid cooling heat dissipation system is composed of a liquid cooling circulating pump, a liquid cooling plate assembly, an air-cooled heat exchanger assembly and other components. Due to its high heat dissipation efficiency, the integrated liquid cooling heat dissipation system has been widely used in the field of electronic equipment. The working environment temperature difference of the integrated liquid cooling heat dissipation system used in a wide temperature environment is large, and a large temperature difference will cause the change of the cold medium accumulation, thereby causing the dramatic change of the internal pressure of the closed circulation system. Therefore, the integrated liquid cooling heat dissipation system used in a wide temperature environment needs to increase a liquid storage expansion tank on the basis of the normal temperature version to cope with the change of the system pressure caused by the change of the cold medium accumulation. Most of the commonly used expansion tanks are rubber balloon type or piston type sealed by a rubber ring. The balloon type has a large volume and is difficult to be integrated at a high density and miniaturized. The piston type sealed by a rubber ring is prone to aging failure in a high and low temperature environment.

[0003] When liquid is injected into the liquid storage expansion tank and the liquid cooling heat dissipation system thereof, the internal cavity volume of the integrated liquid cooling heat dissipation system used at normal temperature is small, and a vacuum injection method is generally used. The internal cavity volume of the integrated liquid cooling heat dissipation system used in a wide temperature environment is large, and the vacuum injection method has low efficiency. The gravity injection method saves the vacuum process and has high efficiency, but the conventional gravity injection method cannot completely discharge the internal air in the closed circulation loop, which affects the heat dissipation efficiency of the system.

[0004] In view of the problems of the large volume of the expansion tank of the integrated liquid cooling heat dissipation system used in a wide temperature environment, the failure of the expansion tank caused by the environment and the problem that the gravity injection method cannot completely discharge the air when liquid is injected, new devices and methods need to be sought to realize the small volume and high reliability of the expansion tank and to optimize the gravity injection method to completely discharge the air in the system. SUMMARY

[0005] The application provides a liquid storage expansion tank liquid injection system, a heat dissipation system thereof, a design method and a liquid injection method. In order to solve the problems of the large volume, low reliability, high efficiency liquid injection and complete air discharge of the liquid storage expansion tank of the integrated liquid cooling heat dissipation system used in a wide temperature, the application uses a stainless steel bellows to construct the liquid storage expansion tank and provides a design selection method. The cross-reverse liquid injection method is used to improve the conventional gravity injection method to realize high efficiency liquid injection and complete air discharge.

[0006] The application achieves the above-mentioned purpose by the following technical solutions. A liquid storage expansion tank injection system includes a liquid storage expansion tank, which includes a tank body. The tank body is internally divided into a left compartment and a right compartment. A one-way valve from right to left connects the left compartment and the right compartment. The tank body is provided with an injection port and a double-channel liquid cooling connector I that communicate with the left compartment, and an exhaust port and a double-channel liquid cooling connector II that communicate with the right compartment. The injection port and the exhaust port are located at the top of the tank body, and the double-channel liquid cooling connector I and the double-channel liquid cooling connector II are located on the side of the tank body.

[0007] Furthermore, it also includes a four-way reversing valve and a refrigerant storage tank. The outlet of the refrigerant storage tank is connected to port 1 of the four-way reversing valve via an injection pump. Port 3 of the four-way reversing valve is connected to the injection port. The drain port is connected to port 4 of the four-way reversing valve. Port 2 of the four-way reversing valve is connected to the inlet of the refrigerant storage tank.

[0008] Furthermore, the left cabin is equipped with a metal bellows.

[0009] A heat dissipation system for a liquid storage expansion tank injection system includes a circulating pump, a liquid-cooled plate assembly, and an air-cooled heat exchanger assembly. It also includes the aforementioned liquid storage expansion tank injection system. A double-channel liquid-cooled connector I is connected to the circulating pump, the circulating pump is connected to the liquid-cooled plate assembly, the liquid-cooled plate assembly is connected to the air-cooled heat exchanger assembly, and the air-cooled heat exchanger assembly is connected to the double-channel liquid-cooled connector II.

[0010] A design method for a liquid filling system for a liquid storage expansion tank, comprising the following steps: Step 1: Calculate the volume change of the refrigerant due to temperature difference; Step 2: Select and design the metal corrugated pipe; Step 3: Calculate the pressure and force that the metal bellows can withstand. If the sum of the pressure difference of the metal bellows and the pressure of the circulating pump is greater than the system design pressure, return to step 2; otherwise, the selection and design of the metal bellows are correct.

[0011] Furthermore, in step 1, the limiting volume change of the refrigerant is calculated as follows:

[0012] In the formula: △V represents the change in the volume of the refrigerant after the actual temperature change. A positive result indicates an increase in volume compared to the original liquid filling state, while a negative result indicates a decrease in volume compared to the original liquid filling state; △T s V represents the actual temperature change. s ρ1 represents the volume of refrigerant filled at the injection temperature; ρ2 represents the limiting density values ​​of the refrigerant measured at different limiting temperatures T1 and T2.

[0013] Furthermore, in step 3, the tensile and compressive forces after the metal bellows is stretched or compressed are calculated as follows:

[0014]

[0015] In the formula: F l The axial tensile force generated by the volume expansion of the bellows; K l Let L be the axial tensile stiffness of a bellows of length L; D be the bellows diameter; F ... axial tensile stiffness of a bellows of length L; F be the axial tensile stiffness of a bellows of length L; D be the bellows diameter; F be the axial tensile stiffness of a bell y The axial compressive force generated by the volume shrinkage of the bellows; K y Let L be the axial compressive stiffness of a bellows of length L.

[0016] Furthermore, in step 3, the volume change of the refrigerant results in the expansion and compression of the metal bellows, which in turn causes a pressure change, calculated as follows:

[0017]

[0018] In the formula: p l K represents the pressure difference between the refrigerant inside the system and the outside atmosphere after the refrigerant expands due to the bellows. l ρ is the axial tensile stiffness of a bellows of length L; D is the bellows diameter; p y K represents the pressure difference between the refrigerant inside the system and the outside atmosphere after the refrigerant contracts in the bellows. y Let L be the axial compressive stiffness of a bellows of length L.

[0019] A liquid injection method for a liquid storage expansion tank injection system, employing the aforementioned liquid storage expansion tank injection system, comprising: Forward liquid injection: Rotate the four-way reversing valve to connect port 1# and port 3#, and simultaneously connect port 2# and port 4#; the liquid injection pump pumps the refrigerant from the refrigerant storage tank, which enters the liquid injection port through port 1# and port 3# of the four-way reversing valve. The refrigerant is injected into the left compartment and rises continuously. Due to the one-way conduction of the check valve, the air in the left compartment is discharged outward through the double-way liquid cooling joint I, and flows into the right compartment after passing through the circulation pump, liquid cooling plate assembly, air-cooled heat exchanger assembly and double-way liquid cooling joint II. Since the pipeline after the drain port is connected to the atmosphere and the pressure is lower than the pressure at the check valve, the air is discharged through the drain port and finally discharged through port 4# and port 2# of the four-way reversing valve. Reverse injection: When refrigerant is discharged from the drain port, rotate the four-way reversing valve to connect ports 1# and 4# internally, and simultaneously connect ports 2# and 3#. The injection pump pumps the refrigerant from the refrigerant storage tank, which then enters the drain port through ports 1# and 4# of the four-way reversing valve, injecting refrigerant into the right compartment. As the refrigerant continuously flows in, the pressure in the right compartment is greater than that in the left compartment. Therefore, the refrigerant flows into the left compartment through the one-way valve. Since the pipeline in the left compartment after the injection port is connected to the atmosphere and the pressure is less than that at the double-way liquid cooling connector I, the liquid level in the left compartment continuously rises, and the air in the upper part is discharged through the injection port. When refrigerant continues to flow into the refrigerant storage tank through port 2# of the four-way reversing valve, it proves that the air in the injection system has been completely purged. Turn off the injection pump, disconnect the injection port and drain port connectors, and complete the closed-loop system injection.

[0020] Furthermore, the circulating pump, liquid-cooled plate assembly, and air-cooled heat exchanger assembly are all designed with low liquid inlet and high liquid outlet, and are connected in series in one direction.

[0021] This application aims to address the problems of large size and environmental susceptibility of commonly used expansion tanks (such as rubber bladder type) in wide-temperature integrated liquid cooling systems, as well as the failure of piston-type systems with rubber ring seals. It also aims to improve the gravity injection method to effectively remove air from the circulation loop while ensuring efficient injection. Therefore, this application achieves the following functions: 1. The expansion tank is constructed using stainless steel corrugated pipes, which solves the problems of large volume, aging of rubber materials due to environmental temperature, and easy failure of the original expansion tank.

[0022] 2. Establish a method for selecting and calculating bellows expansion tanks to solve the problem of proper design of bellows expansion tanks.

[0023] 3. By using a one-way valve and a cross-reverse injection method, the problem that conventional gravity injection methods cannot expel all air in a closed-loop circulation circuit is solved.

[0024] The beneficial effects of this application are: 1. This application utilizes stainless steel bellows, one-way valves, etc. to construct a liquid storage expansion tank, which achieves temperature-sensitive pressure regulation while also taking into account miniaturization and high reliability.

[0025] 2. This application establishes a calculation method for selecting stainless steel bellows expansion tanks, realizing the rational selection and design of liquid storage expansion tanks in integrated liquid cooling heat dissipation systems.

[0026] 3. This application designs a cross-reverse injection method, which improves the traditional gravity injection method, achieves full venting, and does not rely on vacuuming process, thereby improving injection efficiency.

[0027] The aforementioned main solution and its various further alternatives can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed in this application; furthermore, the (non-conflicting alternatives) can also be freely combined with each other and with other alternatives. Those skilled in the art, after understanding the solution of this application, will realize from the prior art and common general knowledge that there are many combinations, all of which are technical solutions to be protected by this application, and will not be exhaustively listed here. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the liquid injection system of this application.

[0029] Figure 2 This is a schematic diagram of the heat dissipation system of this application.

[0030] Figure 3 This is a flowchart illustrating the design method and injection method of this application.

[0031] In the diagram: 1-Tank body, 2-Injection port, 3-Drain port, 4-Check valve, 5-Metal bellows, 6-Double-way liquid cooling structure I, 7-Double-way liquid cooling connector II, 8-Four-way reversing valve, 9-Injection pump, 10-Refrigerant storage tank, 11-Circulation pump, 12-Liquid cooling plate assembly, 13-Air-cooled heat exchanger assembly, 14-Liquid storage expansion pipe, 15-PC pipe Detailed Implementation The following non-limiting embodiments are used to illustrate this application.

[0032] Example 1 refer to Figure 1 As shown, a liquid expansion tank injection system includes a liquid expansion tank 14, a four-way reversing valve 8, an injection pump 9, and a refrigerant storage tank 10. The liquid expansion tank 14 includes a tank body 1, a left compartment, a right compartment, an injection port 2, a drain port 3, a one-way valve 4, a metal bellows 5, a double-way liquid cooling connector I6, and a double-way liquid cooling connector II7.

[0033] The tank 1 is internally divided into a left compartment and a right compartment. A one-way valve 4 connects the left and right compartments from right to left. The left and right compartments are used for liquid supply and liquid return, respectively, to separate the functions of the compartments. The one-way valve 4 is used for the one-way flow of refrigerant, ensuring that only the refrigerant can flow in one direction, and preventing gas from flowing between the two compartments.

[0034] The tank body 1 is equipped with a liquid injection port 2 and a double-channel liquid cooling connector I6 that communicate with the left compartment. The tank body 1 is also equipped with a liquid drain port 3 and a double-channel liquid cooling connector II7 that communicate with the right compartment. The liquid injection port 2 is used to receive the stored refrigerant or to vent the gas. The liquid drain port 3 is used to store the returned refrigerant. The double-channel liquid cooling connector I6 and the double-channel liquid cooling connector II7 are used to supply liquid to the heat dissipation system and to recover the refrigerant from the heat dissipation system, respectively.

[0035] Injection port 2 and drain port 3 are located at the top of tank body 1, and double-channel liquid cooling connector I6 and double-channel liquid cooling connector II7 are located on the side of tank body 1. The double-channel liquid cooling connectors are located on the side to ensure that they are lower than the injection port 2 and drain port 3 at the top, so as to facilitate venting through the injection port 2 and drain port 3 at the top.

[0036] The outlet of the refrigerant storage tank 10 is connected to port 1 of the four-way directional valve 8 via a liquid injection pump 9. The liquid injection pump 9 is preferably a gear pump, which pumps the refrigerant in the storage tank to the liquid expansion tank 14. Port 3 of the four-way directional valve 8 is connected to the liquid injection port 2, the liquid discharge port 3 is connected to port 4 of the four-way directional valve 8, and port 2 of the four-way directional valve 8 is connected to the inlet of the refrigerant storage tank 10.

[0037] The four-way reversing valve 8 is used for switching refrigerant delivery. When injecting refrigerant in the forward direction and venting the right compartment, port 1# and port 3# of the four-way reversing valve 8 are connected, and port 2# and port 4# are connected at the same time. When injecting refrigerant in the reverse direction and venting the left compartment, port 1# and port 4# of the four-way reversing valve 8 are connected, and port 2# and port 3# are connected at the same time.

[0038] The left compartment is equipped with a metal bellows 5, preferably made of stainless steel. This bellows is compressible under pressure and, because it is integrated into the pressurized environment of the tank 1, it can dynamically match the internal pressurization environment, thus buffering the internal pressure. By utilizing the expansion and contraction of the metal bellows 5 with pressure changes, the volume expansion and contraction of the refrigerant within the system due to temperature changes is regulated, keeping the internal pressure within a certain range and preventing overpressure, leakage, or damage to the liquid cooling system.

[0039] All connecting pipelines use PC pipe 15.

[0040] Example 2 refer to Figure 1 and Figure 2 As shown, a heat dissipation system for a liquid expansion tank filling system includes a circulating pump 11, a liquid-cooled plate assembly 12, and an air-cooled heat exchanger assembly 13, and also includes the liquid expansion tank filling system of Embodiment 1. A double-port liquid-cooled connector I6 is connected to the circulating pump 11, the circulating pump 11 is connected to the liquid-cooled plate assembly 12, the liquid-cooled plate assembly 12 is connected to the air-cooled heat exchanger assembly 13, and the air-cooled heat exchanger assembly 13 is connected to the double-port liquid-cooled connector II7.

[0041] Before normal heat dissipation, the heat dissipation system needs to be filled with liquid and vented through the liquid injection system. During normal heat dissipation, the liquid injection system does not work, and the liquid storage expansion tank 14 is used normally as a liquid supply and return tank. The circulation pump (drive pump) of the heat dissipation system realizes the circulation supply of refrigerant. The refrigerant circulates to absorb and dissipate heat, thereby achieving heat dissipation and cooling of specific equipment.

[0042] All connecting pipelines use PC pipe 15.

[0043] Example 3 refer to Figure 3 As shown, a design method for a liquid storage expansion tank injection system, specifically for the liquid storage expansion tank injection system of Example 1, includes the following steps: Step 1, calculate the volume change of refrigerant due to temperature difference.

[0044] In step 1, factors such as the amount of refrigerant injected into the heat dissipation system and the extreme temperature change determine the design and selection boundary conditions of the bellows. The extreme volume change of the refrigerant is calculated as follows:

[0045] In the formula: △V represents the change in the volume of the refrigerant after the actual temperature change. A positive result indicates an increase in volume compared to the original liquid filling state, while a negative result indicates a decrease in volume compared to the original liquid filling state; △T s V represents the actual temperature change. s ρ1 represents the volume of refrigerant filled at the injection temperature; ρ2 represents the limiting density values ​​of the refrigerant measured at different limiting temperatures T1 and T2.

[0046] Step 2: Select and design the metal corrugated pipe 5.

[0047] Step 3: Calculate the pressure and stress that the metal bellows 5 can withstand. If the sum of the pressure difference of the metal bellows 5 and the pressure of the circulating pump 11 is greater than the system design pressure, return to step 2. It is necessary to increase the bellows interface diameter or increase the bellows length. Otherwise, the selection and design of the metal bellows 5 are correct.

[0048] In step 3, the compression and tension stiffness of the bellows are different, so the forces acting on it need to be calculated separately. The tensile and compressive forces of the metal bellows 5 after tensile or compressive deformation are calculated as follows:

[0049]

[0050] In the formula: F l The axial tensile force generated by the volume expansion of the bellows; K l Let L be the axial tensile stiffness of a bellows of length L; D be the bellows diameter; F ... axial tensile stiffness of a bellows of length L; F be the axial tensile stiffness of a bellows of length L; D be the bellows diameter; F be the axial tensile stiffness of a bell y The axial compressive force generated by the volume shrinkage of the bellows; K y Let L be the axial compressive stiffness of a bellows of length L.

[0051] In step 3, the volume change of the refrigerant results in the expansion and compression of the metal bellows 5, which in turn causes a pressure change, calculated as follows:

[0052]

[0053] In the formula: p l K represents the pressure difference between the refrigerant inside the system and the outside atmosphere after the refrigerant expands due to the bellows. l ρ is the axial tensile stiffness of a bellows of length L; D is the bellows diameter; p y K represents the pressure difference between the refrigerant inside the system and the outside atmosphere after the refrigerant contracts in the bellows. y Let L be the axial compressive stiffness of a bellows of length L.

[0054] Example 4 refer to Figures 1-3 As shown, a liquid injection method for a liquid storage expansion tank injection system does not rely on a vacuum pump for vacuuming. By improving the gravity injection method, efficient liquid injection and complete venting are achieved. Specifically, the liquid storage expansion tank injection system of Example 1 is used, including forward injection and reverse injection.

[0055] Forward injection: Rotate the four-way reversing valve 8 to connect port 1# and port 3#, and simultaneously connect port 2# and port 4#. The injection pump 9 pumps the refrigerant from the refrigerant storage tank 10, which enters the injection port 2 through ports 1# and 3# of the four-way reversing valve 8. The refrigerant is injected into the left compartment and rises continuously. Due to the one-way conduction of the check valve 4, the air in the left compartment is discharged outward through the double-way liquid cooling connector I6, and flows into the right compartment after passing through the circulation pump 11, the liquid cooling plate assembly 12, the air-cooled heat exchanger assembly 13, and the double-way liquid cooling connector II7. Since the pipeline after the drain port 3 is connected to the atmosphere and the pressure is lower than that at the check valve 4, the air in the right compartment is discharged through the drain port 3, and finally discharged through ports 4# and 2# of the four-way reversing valve 8.

[0056] The circulating pump 11, liquid-cooled plate assembly 12, and air-cooled heat exchanger assembly 13 are all designed with low liquid inlets and high liquid outlets, and are connected in unidirectional series. Therefore, when liquid is discharged from outlet 3, it means that all the air inside the closed-loop system except for the liquid storage expansion tank has been completely discharged, and the right compartment of the liquid storage expansion tank 14 is full of refrigerant. However, there is no outlet for air in the space on the left side of the liquid storage expansion tank 14 beyond the height of the double-pass liquid-cooled connector I6, and some air remains.

[0057] Reverse injection: When refrigerant is discharged from drain port 3, rotate the four-way reversing valve 8 to connect ports 1# and 4# internally, and simultaneously connect ports 2# and 3#. The injection pump 9 pumps the refrigerant from the refrigerant storage tank 10, which then flows through ports 1# and 4# of the four-way reversing valve 8 into drain port 3, injecting refrigerant into the right compartment. As the refrigerant continuously flows in, the pressure in the right compartment is greater than that in the left compartment. Therefore, the refrigerant flows into the left compartment through the one-way valve 4. Since the pipe in the left compartment after injection port 2 is connected to the atmosphere and the pressure is less than that at the double-way liquid cooling connector I6, the liquid level in the left compartment continuously rises, and the upper part of the air is discharged through injection port 2. When refrigerant continuously flows into the refrigerant storage tank 10 through port 2 of the four-way reversing valve 8, it proves that the air in the injection system has been completely purged. Turn off the injection pump 9, disconnect the connector between injection port 2 and drain port 3, and the closed-loop system injection is complete.

[0058] The foregoing basic examples and their further alternative examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed in this application. In the scheme of this application, each alternative example can be arbitrarily combined with any other basic example and alternative example.

[0059] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A liquid storage expansion tank injection system, comprising a liquid storage expansion tank (14), characterized in that: The liquid storage expansion tank (14) includes a tank body (1), which is divided into a left compartment and a right compartment. A one-way valve (4) from right to left connects the left compartment and the right compartment. The tank body (1) is provided with an injection port (2) and a double-channel liquid cooling connector I (6) connected to the left compartment. The tank body (1) is provided with a drain port (3) and a double-channel liquid cooling connector II (7) connected to the right compartment. The injection port (2) and the drain port (3) are located at the top of the tank body (1), and the double-channel liquid cooling connector I (6) and the double-channel liquid cooling connector II (7) are located on the side of the tank body (1).

2. The liquid injection system for the storage expansion tank according to claim 1, characterized in that: It also includes a four-way reversing valve (8) and a refrigerant storage tank (10). The outlet of the refrigerant storage tank (10) is connected to port 1 of the four-way reversing valve (8) via a liquid injection pump (9). Port 3 of the four-way reversing valve (8) is connected to the liquid injection port (2). The drain port (3) is connected to port 4 of the four-way reversing valve (8). Port 2 of the four-way reversing valve (8) is connected to the inlet of the refrigerant storage tank (10).

3. The liquid injection system for the liquid storage expansion tank according to claim 1, characterized in that: The left cabin is equipped with a metal bellows (5).

4. A heat dissipation system for a liquid expansion tank injection system, comprising a circulating pump (11), a liquid-cooled plate assembly (12), and an air-cooled heat exchanger assembly (13), characterized in that: It also includes the liquid filling system of the storage expansion tank according to any one of claims 1 to 3, wherein the double-pass liquid cooling connector I (6) is connected to the circulation pump (11), the circulation pump (11) is connected to the liquid cooling plate assembly (12), the liquid cooling plate assembly (12) is connected to the air-cooled heat exchanger assembly (13), and the air-cooled heat exchanger assembly (13) is connected to the double-pass liquid cooling connector II (7).

5. A design method for a liquid injection system for a liquid storage expansion tank, characterized in that, The liquid filling system for the storage expansion tank according to claim 3 includes the following steps: Step 1: Calculate the volume change of the refrigerant due to temperature difference; Step 2, select and design the metal corrugated pipe (5); Step 3: Calculate the pressure and stress of the metal bellows (5). If the sum of the pressure difference of the metal bellows (5) and the pressure of the circulating pump (11) is greater than the system design pressure, return to step 2. Otherwise, the selection and design of the metal bellows (5) are correct.

6. The design method of the liquid injection system for the liquid storage expansion tank according to claim 5, characterized in that: In step 1, the limiting volume change of the refrigerant is calculated as follows: In the formula: △V represents the change in the volume of the refrigerant after the actual temperature change. A positive result indicates an increase in volume compared to the original liquid filling state, while a negative result indicates a decrease in volume compared to the original liquid filling state; △T s V represents the actual temperature change. s ρ1 represents the volume of refrigerant filled at the injection temperature; ρ2 represents the limiting density values ​​of the refrigerant measured at different limiting temperatures T1 and T2.

7. The design method of the liquid injection system for the liquid storage expansion tank according to claim 6, characterized in that: In step 3, the tensile force and compressive force of the metal bellows (5) after stretching or compressing deformation are calculated as follows: In the formula: F l The axial tensile force generated by the volume expansion of the bellows; K l Let L be the axial tensile stiffness of a bellows of length L; D be the bellows diameter; F ... axial tensile stiffness of a bellows of length L; F be the axial tensile stiffness of a bellows of length L; D be the bellows diameter; F be the axial tensile stiffness of a bell y The axial compressive force generated by the volume shrinkage of the bellows; K y Let L be the axial compressive stiffness of a bellows of length L.

8. The design method of the liquid injection system for the liquid storage expansion tank according to claim 6, characterized in that: In step 3, the volume change of the refrigerant results in the expansion and compression of the metal bellows (5), which in turn causes a pressure change, calculated as follows: In the formula: p l K represents the pressure difference between the refrigerant inside the system and the outside atmosphere after the refrigerant expands due to the bellows. l ρ is the axial tensile stiffness of a bellows of length L; D is the bellows diameter; p y K represents the pressure difference between the refrigerant inside the system and the outside atmosphere after the refrigerant contracts in the bellows. y Let L be the axial compressive stiffness of a bellows of length L.

9. A liquid injection method for a liquid expansion tank injection system, characterized in that, The liquid filling system for the storage expansion tank according to any one of claims 2 to 3 includes: Forward injection: Rotate the four-way reversing valve (8) to connect port 1# and port 3#, and at the same time connect port 2# and port 4#; the injection pump (9) pumps the refrigerant from the refrigerant storage tank (10) out, and enters the injection port (2) through port 1# and port 3# of the four-way reversing valve (8). The refrigerant is injected into the left compartment and rises continuously. Due to the one-way conduction of the check valve (4), the air in the left compartment is discharged outward through the double-way liquid cooling connector I (6), and flows into the right compartment after passing through the circulation pump (11), liquid cooling plate assembly (12), air-cooled heat exchanger assembly (13) and double-way liquid cooling connector II (7). Since the pipeline after the drain port (3) is connected to the atmosphere and the pressure is lower than the pressure at the check valve (4), the air is discharged through the drain port (3) and finally discharged through port 4# and port 2# of the four-way reversing valve (8). Reverse injection: When refrigerant is discharged from the drain port (3), rotate the four-way reversing valve (8) to connect port 1# and port 4# internally, and at the same time connect port 2# and port 3#; the injection pump (9) pumps the refrigerant from the refrigerant storage tank (10) out, and enters the drain port (3) through port 1# and port 4# of the four-way reversing valve (8), injecting the refrigerant into the right compartment. As the refrigerant continuously flows in, the pressure in the right compartment is greater than that in the left compartment. Therefore, the refrigerant flows into the left compartment through the one-way valve (4), and is then injected into the right compartment. The pipeline in the left compartment is connected to the atmosphere through the injection port (2) and the pressure is less than that at the double-pass liquid cooling connector I (6). Therefore, the liquid level in the left compartment continues to rise, and the upper part of the air is discharged through the injection port (2). When refrigerant continuously flows into the refrigerant storage tank (10) through the No. 2 port of the four-way reversing valve (8), it proves that the air in the injection system has been exhausted. The injection pump (9) is turned off, and the connection between the injection port (2) and the drain port (3) is pulled out to complete the injection of the closed-loop system.

10. The liquid injection method of the liquid storage expansion tank injection system according to claim 9, characterized in that: The circulating pump (11), liquid cooling plate assembly (12), and air-cooled heat exchanger assembly (13) are all designed with low liquid inlet and high liquid outlet, and are connected in series in one direction.

Images