Passive pulse type two-phase flow enhanced heat exchanger based on Tesla valve

Abstract

The invention provides a passive pulse type two-phase flow enhanced heat exchanger based on a Tesla valve. The heat exchanger comprises a special unit body, a cooling pipeline, a liquid injection valve and a liquid outlet valve. The special unit body is connected with the cooling pipeline, and the liquid injection valve and the liquid outlet valve are located above the cooling pipeline; a flowing working medium FC-72 is injected into the heat exchanger through a liquid injection valve; the special unit body comprises a heating pipeline and two Tesla valve pipelines; and the Tesla valve pipeline is a multi-stage Tesla valve pipeline formed by connecting two Tesla valves. Compared with an existing heat exchange system, efficient one-way pulsating circulation can be conducted along the preset path, the power is converted into power for driving a working medium to continuously circulate in a pipeline under the guidance of the Tesla valve, efficient conversion and utilization of energy are achieved, and energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchange, and particularly to a non-powered pulsed two-phase flow enhanced heat exchanger based on a Tesla valve. Background Art

[0002] In recent years, lithium batteries have been widely used in electric vehicles due to their high specific energy and energy density, which are superior to other rechargeable batteries. However, a large amount of heat is generated during the charging and discharging of lithium batteries, and this heat is waste heat for the battery. Especially in summer, excessive temperature will cause the performance of the battery to decrease, affect the battery life, and may even cause an explosion in severe cases. Therefore, once the thermal management of the battery is improper, the consequences will be catastrophic. Once a lithium battery undergoes thermal runaway, the energy that the entire battery pack can release is astonishing. Through research and analysis, it is known that for a battery pack composed of 100 battery cells with a charge capacity of 100 Ah, the runaway energy reaches 240 MJ, which is approximately equivalent to 57 kg of TNT explosives. Therefore, how to effectively eliminate the waste heat generated during the charging and discharging of the battery is a factor that needs to be considered in electric vehicles.

[0003] Currently, in the field of battery heat dissipation, there are mainly four existing technical solutions: (1) Passive heat dissipation: It refers to a method of dissipating heat without using any active devices and working fluids, such as fans or water pumps, but relying on the heat diffusion, radiation, and natural convection of the material itself. (2) Air-cooled heat dissipation: It refers to using a device such as a fan to create an air flow through the heat source to take away the heat. (3) Liquid-cooled heat dissipation: It refers to using a water pump to use water or other coolants with a high specific heat capacity to take the heat of the heat source to the radiator and circulate to take away the heat, and the process does not involve the phase change of the working fluid. (4) Heat pipe heat dissipation: A heat pipe is a closed pipe containing a small amount of working fluid. The working fluid evaporates at the heat source and takes away the heat, then condenses and releases the heat at the cold source at the other end of the pipe, and then the working fluid flows back to the heat source. Due to its full utilization of the heat conduction principle and the rapid heat transfer property of the phase change medium, it has a wide range of applications in many fields.

[0004] Currently, there are many problems with the thermal management methods used for lithium batteries. For example, the heat dissipation uniformity of air-cooling is poor, and it requires more external driving energy. Although liquid-cooling has better heat exchange performance than air-cooling, it has additional facilities such as water pumps and water tanks, occupying a large amount of space.

[0005] Therefore, in view of the above-mentioned many problems of battery thermal management, it is urgent to research and develop a new type of non-powered pulsed two-phase flow enhanced heat exchanger. Summary of the Invention

[0006] The object of the present invention is to solve a series of problems existing in the existing battery thermal management methods, such as poor heat dissipation uniformity, low space utilization rate, and the need for external energy drive. A non-energy-pulsed two-phase flow enhanced heat exchanger based on a Tesla valve is proposed.

[0007] The present invention is realized through the following technical solutions. The present invention proposes a non-energy-pulsed two-phase flow enhanced heat exchanger based on a Tesla valve. The non-energy-pulsed two-phase flow enhanced heat exchanger based on a Tesla valve includes a special unit body 1, a cooling pipe 2, a liquid injection valve 3, and a liquid outlet valve 4; the special unit body 1 is connected to the cooling pipe 2, and the liquid injection valve 3 and the liquid outlet valve 4 are located above the cooling pipe 2; the flowing working medium - FC-72 is injected into the heat exchanger through the liquid injection valve 3; the special unit body 1 includes a heating pipe 6 and two Tesla valve pipes 7; the Tesla valve pipe 7 is a multi-stage Tesla valve pipe formed by connecting two Tesla valves 8.

[0008] Further, the liquid injection valve 3 and the liquid outlet valve 4 are in symmetric positions on the entire transducer.

[0009] Further, first inject the flowing working medium - FC-72 into the pipe through the liquid injection valve 3, then fix the heat exchanger on a centrifugal device, and through the centrifugal action, make the flowing working medium - FC-72 evenly distributed in the pipe. Then fix the heat exchanger on a heating platform for heating. The flowing working medium - FC-72 undergoes a phase change in the heating pipe 6 to carry out two-phase flow. The gaseous working medium cools and releases heat during the process of flowing through the Tesla valve pipe 7 and the cooling pipe 2. At the same time, by using the one-way conductivity of the Tesla valve, the flowing working medium - FC-72 generates a one-way circulating flow in the entire heat exchanger.

[0010] Further, the liquid injection valve 3 is connected to a vacuum pump. Open the liquid injection valve 3 and close the liquid outlet valve 4. Pump the inside of the heat exchanger to a vacuum state through the vacuum pump, and then inject the flowing working medium - FC-72 at a filling rate of 60%. Close the liquid injection valve 3; fix the filled heat exchanger on a centrifugal device and make the flowing working medium - FC-72 evenly distributed in the pipe at a rotation speed of 5000 r / min; when it is necessary to replace the flowing working medium, open the liquid injection valve 3 and the liquid outlet valve 4 at the same time. The liquid injection valve 3 is connected to an air pump. Start the air pump to pump the flowing working medium in the heat exchanger out from the liquid outlet valve 4.

[0011] Further, the number of the special unit bodies 1 and the cooling pipes 2 is 24 each, forming a circular array and connecting to form a heat exchanger monomer.

[0012] Furthermore, the flowing working fluid - FC-72 is heated in the heating pipe 6, undergoes a phase change, generates gas plugs, and is pushed to expand and flow in both directions for two-phase flow heat transfer. The flow state changes from laminar flow to turbulent flow, the boundary layer is disrupted, and its heat transfer coefficient is increased. Due to the pressure difference at both ends of the Tesla valve pipe 7, the flowing working fluid - FC-72 tends to flow in the direction with a smaller pressure difference. When the two-phase flowing working fluid - FC-72 flows through the cooling pipe 2, the bubbles cool, shrink, and burst, resulting in a pressure drop, which further promotes the pulsation of the flowing working fluid - FC-72 in the heat exchanger.

[0013] Furthermore, the Tesla valve 8 is composed of curved pipes and straight pipes. When the flowing working fluid - FC-72 flows in from the inlets at both ends of the Tesla valve 8 respectively, there will be obvious differences in the flow distribution of the working fluid. When the working fluid flows in the forward direction, the Tesla valve 8 does not affect the flow of the working fluid. When the working fluid flows in the reverse direction, the working fluid flowing out of the curved pipe will hinder the working fluid flowing out of the straight pipe, generating a pressure drop and hindering the flow of the working fluid. This phenomenon is the unidirectional flow property of the Tesla valve 8.

[0014] Furthermore, the Tesla valve pipe 7 is a multi-stage Tesla valve pipe formed by connecting 2 Tesla valves 8 in a symmetric form, which strengthens the unidirectional flow property of the Tesla valve 8.

[0015] The beneficial effects of the present invention are as follows:

[0016] 1. Closed-loop unidirectional self-circulation: Compared with the existing heat exchange system, the present invention does not require an external input work similar to a pump to drive the flow of the working fluid in the pipe. By utilizing the unidirectional conductivity of the Tesla valve and carefully designing and arranging it at key positions in the pipe, it ensures that the working fluid can perform an efficient unidirectional pulsating cycle along the preset path under the action of heat expansion or temperature difference drive. The physical property changes of the working fluid during the heating process, especially the thermal expansion effect, and the natural convection phenomenon caused by the temperature difference between different positions are transformed into the driving force for the continuous circulation of the working fluid in the pipe under the guidance of the Tesla valve, realizing the efficient conversion and utilization of energy and reducing energy consumption.

[0017] 2. Strong heat exchange performance: Compared with the existing heat exchange system, the present invention transfers and transfers heat through the phase change heat transfer of the working fluid in the pipe. The flowing working fluid absorbs heat in the heating section, changes from the liquid phase to the gas phase, generates gas plugs. In the cooling section, the gas plugs burst. Relying on the unbalanced pressure difference during the phase change process of the working fluid as the driving force, and at the same time, the flow state of the working fluid changes from laminar flow to turbulent flow, the boundary layer is disrupted, and the heat transfer coefficient of the working fluid can be significantly increased. Therefore, the heat exchange performance is greatly enhanced, showing super heat conductivity.

[0018] 3. High space utilization rate: Compared with traditional liquid cooling systems and existing self - circulating heat exchange systems, the present invention eliminates components such as water pumps and water tanks that occupy a large amount of space, making the internal layout of the device more compact and reasonable. This improves the integration and performance of the overall system, as well as the maintainability and system expandability by simplifying the system structure. Its design is suitable for a variety of installation environments and application scenarios, such as fields with limited space like automotive batteries, where efficient heat dissipation and space optimization are required, significantly improving the space utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is an isometric view of the single - stage structure of the present invention;

[0020] Figure 2 is Figure 1 a cross - sectional view of the special unit 1 in

[0021] Figure 3 is Figure 2 the top view of

[0022] Figure 4 is Figure 1 a cross - sectional view of the entire cooling pipe 2 and valves 3 or 4 in

[0023] Figure 5 is Figure 4 the top view of

[0024] Figure 6 is Figure 1 a cross - sectional view of the Tesla valve pipe 7 in

[0025] Figure 7 is Figure 6 the top view of

[0026] Figure 8 is an isometric view of the overall structure of the present invention;

[0027] Figure 9 is Figure 8 the top view of

[0028] Figure 10 is Figure 8 the front view of

[0029] In the figure: 1 - special unit; 2 - cooling pipe; 3 - liquid injection valve; 4 - liquid outlet valve; 6 - heating pipe; 7 - Tesla valve pipe; 8 - Tesla valve. DETAILED DESCRIPTION OF THE INVENTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] Referring to Figures 1-10 , the present invention provides a non-powered pulsed two-phase flow enhanced heat exchanger based on a Tesla valve. The non-powered pulsed two-phase flow enhanced heat exchanger based on a Tesla valve includes a special unit body 1, a cooling pipe 2, a liquid injection valve 3 and a liquid outlet valve 4; the special unit body 1 is connected to the cooling pipe 2; the liquid injection valve 3 and the liquid outlet valve 4 are located above the cooling pipe 2; the flowing working fluid - FC-72 is injected into the heat exchanger through the liquid injection valve 3; the special unit body 1 includes a heating pipe 6 and two Tesla valve pipes 7; the Tesla valve pipe 7 is a multi-stage Tesla valve pipe formed by connecting two Tesla valves 8. The liquid injection valve 3 and the liquid outlet valve 4 are symmetrically positioned on the entire transducer.

[0032] The heat exchanger first injects the flowing working fluid - FC-72 into the pipe through the liquid injection valve 3, then fixes the heat exchanger on a centrifugal device, and makes the flowing working fluid - FC-72 evenly distributed in the pipe by centrifugal action. Then, the heat exchanger is fixed on a heating platform for heating. The flowing working fluid - FC-72 undergoes a phase change in the heating pipe 6 to perform two-phase flow. The gaseous working fluid releases heat during cooling while flowing through the Tesla valve pipe 7 and the cooling pipe 2. At the same time, by utilizing the unidirectional conductivity of the Tesla valve, the flowing working fluid - FC-72 generates a non-powered unidirectional circulating flow in the entire heat exchanger. The technical solutions of the present invention are not limited to the specific embodiments listed below, and also include any reasonable combination between the specific embodiments.

[0033] Specific Embodiment 1: In combination with Figures 1 to 7 This embodiment is described. A non-powered pulsed two-phase flow enhanced heat exchanger based on a Tesla valve applied to a lithium battery according to this embodiment includes a cooling pipe 2, a liquid injection valve 3, a liquid outlet valve 4 and a flowing working fluid - FC-72. Both the liquid injection valve 3 and the liquid outlet valve 4 are located above the cooling pipe 2 and are symmetrically positioned on the entire heat exchanger.

[0034] The liquid injection valve 3 is connected to a vacuum pump. Open the liquid injection valve 3, close the liquid outlet valve 4, and use the vacuum pump to evacuate the interior of the heat exchanger to a vacuum state. Then, inject the flowing working fluid - FC-72 at a filling rate of 60%, and close the liquid injection valve 3. Fix the filled heat exchanger on a centrifugal device and rotate it at a speed of 5000 r / min to evenly distribute the flowing working fluid - FC-72 in the pipe. When it is necessary to replace the flowing working fluid, open the liquid injection valve 3 and the liquid outlet valve 4 simultaneously. The liquid injection valve 3 is connected to an air pump. Start the air pump to pump out the flowing working fluid in the heat exchanger from the liquid outlet valve 4. This process is the liquid injection and liquid replacement stage of the heat exchanger.

[0035] Specific Embodiment 2: In combination with Figures 1 to 7 To illustrate this embodiment, a Tesla valve-based non-energy pulse two-phase flow enhanced heat exchanger applied to a lithium battery described in this embodiment includes a special unit body 1, a cooling pipe 2, and a flowing working fluid - FC-72. The special unit body 1 includes a heating pipe 6 and two Tesla valve pipes 7. The cooling pipes 2 are respectively connected to adjacent special unit bodies 1. The number of special unit bodies 1 and cooling pipes 2 is 24 each, forming a circular array and connecting to form a heat exchanger monomer.

[0036] The flowing working fluid - FC-72 is heated in the heating pipe 6, undergoes a phase change, generates gas plugs, and is pushed to expand and flow to both sides for two-phase flow heat transfer. The flow state changes from laminar flow to turbulent flow, and the boundary layer is destroyed, resulting in an increase in its heat transfer coefficient. Due to the pressure difference at both ends of the Tesla valve pipe 7, the flowing working fluid - FC-72 tends to flow in the direction with a smaller pressure difference. When the two-phase flowing working fluid - FC-72 flows through the cooling pipe 2, the bubbles cool, shrink, and burst, causing the pressure to drop, further promoting the pulsation of the flowing working fluid - FC-72 in the heat exchanger. Compared with the heat dissipation method of single-phase flow, the process of the present invention involves two-phase flow heat transfer and has a good heat transfer effect.

[0037] Specific Embodiment 3: In combination with Figures 6 to 7 To illustrate this embodiment, a Tesla valve-based non-energy pulse two-phase flow enhanced heat exchanger applied to a lithium battery described in this embodiment includes a Tesla valve pipe 7. The Tesla valve pipe 7 is a multi-stage Tesla valve pipe formed by connecting two special Tesla valves 8.

[0038] The Tesla valve 8 is composed of bent pipes and straight pipes. When the flowing working fluid - FC-72 flows in from the inlets at both ends of the Tesla valve 8 respectively, there will be obvious differences in the flow distribution of the working fluid. When the working fluid flows in the forward direction, the Tesla valve 8 basically does not affect the flow of the working fluid. When the working fluid flows in the reverse direction, the working fluid flowing out of the bent pipe will hinder the working fluid flowing out of the straight pipe, generating an obvious pressure drop and greatly hindering the flow of the working fluid. This phenomenon is the unidirectional flow property of the Tesla valve 8. The Tesla valve pipe 7 is a multi-stage Tesla valve pipe formed by connecting 2 Tesla valves 8, adopting a symmetrical form, which strengthens the unidirectional flow property of the Tesla valve 8. While further promoting the forward flow of the flowing working fluid - FC-72, it also greatly improves the space utilization rate.

[0039] Specific Embodiment 4: Combining Figures 8 to 10 To illustrate this embodiment, an inertially pulsed two-phase flow enhanced heat exchanger based on a Tesla valve for a lithium battery described in this embodiment includes a special unit 1, a cooling pipe 2, and a flowing working fluid - FC-72. The special unit 1 includes a heating pipe 6 and 2 Tesla valve pipes 7. The number of the special unit 1 and the cooling pipe 2 is 24 each, forming a circular array and connecting to form a single-stage heat exchanger body.

[0040] The present invention can design multi-stage devices with different circular diameters of arrays by reducing the number of circular arrays. The devices at all levels can be combined together in a multi-stage nested manner. In the same heating area, compared with the single-stage device, the multi-stage nested device makes the internal layout of the device more compact and reasonable, thereby improving the integration and performance of the overall system, as well as enhancing the maintainability and system expandability by simplifying the system structure. The flowing working fluid - FC-72 in the pipes at all levels simultaneously undergoes an inertially pulsed two-phase cyclic flow, enhancing the heat transfer effect and improving the space utilization rate.

[0041] The above is only a preferred embodiment of the present invention and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to obtain equivalent embodiments with equivalent changes. However, as long as it does not depart from the technical content of the present invention and is based on the technical essence of the present invention, any simple modification, equivalent replacement, and improvement made to the above embodiments within the spirit and principle of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A non-energy-consuming pulsating two-phase flow enhanced heat exchanger based on a Tesla valve, characterized in that, The non-energy pulse two-phase flow enhanced heat exchanger based on a Tesla valve includes a special unit (1), a cooling pipe (2), a liquid injection valve (3), and a liquid outlet valve (4); the special unit (1) is connected to the cooling pipe (2), and the liquid injection valve (3) and the liquid outlet valve (4) are located above the cooling pipe (2); the flowing working medium - FC-72 is injected into the heat exchanger through the liquid injection valve (3); the special unit (1) includes a heating pipe (6) and two Tesla valve pipes (7); the Tesla valve pipe (7) is a multi-stage Tesla valve pipe formed by connecting two Tesla valves (8).

2. The heat exchanger according to claim 1, characterized in that, The liquid injection valve (3) and the liquid outlet valve (4) are in symmetric positions on the entire transducer.

3. The heat exchanger according to claim 1, characterized in that, First, inject the flowing working medium - FC-72 into the pipe through the liquid injection valve (3), then fix the heat exchanger on a centrifugal device, and through centrifugal action, make the flowing working medium - FC-72 evenly distributed in the pipe. Then fix the heat exchanger on a heating platform for heating. The flowing working medium - FC-72 undergoes a phase change in the heating pipe (6) to carry out two-phase flow. The gaseous working medium cools and releases heat during the process of flowing through the Tesla valve pipe (7) and the cooling pipe (2). At the same time, by using the unidirectional conduction of the Tesla valve, the flowing working medium - FC-72 generates a unidirectional circulating flow in the entire heat exchanger.

4. The heat exchanger according to claim 3, wherein, The liquid injection valve (3) is connected to a vacuum pump. Open the liquid injection valve (3), close the liquid outlet valve (4), and evacuate the inside of the heat exchanger to a vacuum state through the vacuum pump. Then inject the flowing working medium - FC-72 at a filling rate of 60%, and close the liquid injection valve (3); fix the filled heat exchanger on a centrifugal device and make the flowing working medium - FC-72 evenly distributed in the pipe at a rotational speed of 5000 r / min; when it is necessary to replace the flowing working medium, open the liquid injection valve (3) and the liquid outlet valve (4) simultaneously. The liquid injection valve (3) is connected to an air pump, start the air pump, and pump out the flowing working medium in the heat exchanger from the liquid outlet valve (4).

5. The heat exchanger according to claim 1, wherein The number of the special unit (1) and the cooling pipe (2) is 24 each, forming a circular array and connecting to form a heat exchanger monomer.

6. The heat exchanger according to claim 1, characterized in that The flowing working medium - FC-72 is heated in the heating pipe (6), undergoes a phase change, generates air plugs, and is pushed to expand and flow to both sides to carry out two-phase flow heat transfer. The flow state changes from laminar flow to turbulent flow, the boundary layer is destroyed, and its heat transfer coefficient is improved; due to the pressure difference at both ends of the Tesla valve pipe (7), the flowing working medium - FC-72 tends to flow in the direction with a smaller pressure difference; when the two-phase flowing working medium - FC-72 flows through the cooling pipe (2), the bubbles cool, shrink, and burst, the pressure drops, which further promotes the pulsation of the flowing working medium - FC-72 in the heat exchanger.

7. The heat exchanger according to claim 1, characterized in that, The Tesla valve (8) is composed of bent pipes and straight pipes. When the flowing working fluid - FC-72 flows into the Tesla valve (8) from the inlets at both ends respectively, there will be obvious differences in the flow distribution of the working fluid. When the working fluid flows in the forward direction, the Tesla valve (8) does not affect the flow of the working fluid. When the working fluid flows in the reverse direction, the working fluid flowing out of the bent pipe will hinder the working fluid flowing out of the straight pipe, generating a pressure drop and hindering the flow of the working fluid. This phenomenon is the unidirectional flow property of the Tesla valve (8).

8. The heat exchanger according to claim 7, characterized in that, The Tesla valve pipeline (7) is a multi-stage Tesla valve pipeline formed by connecting 2 Tesla valves (8), adopting a symmetrical form, which strengthens the unidirectional flow property of the Tesla valve (8).

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