Pulsating heat pipe system with extended heat exchange area

Abstract

The application provides a pulsating heat pipe system with expanded heat exchange area, which comprises a pulsating heat pipe, the pulsating heat pipe comprises a lower bending structure and an upper bending structure, the lower bending structure comprises vertical pipes extending in the up-down direction and connecting pipes connecting the upper and lower ends of adjacent vertical pipes, the upper bending structure comprises horizontal pipes extending in the left-right direction and connecting pipes connecting the left and right ends of adjacent horizontal pipes, the upper bending structure and the lower bending structure form a series loop structure through the connecting pipes, the pulsating heat pipe comprises an evaporation end and a condensation end, the evaporation end comprises the lower part of the lower bending structure, and the condensation end comprises the upper part of the lower bending structure and the upper bending structure. The pulsating heat pipe system with expanded heat exchange area is provided, and the setting of the upper bending structure can increase the heat exchange area of the condensation end and improve the heat exchange effect.

Description

A pulsating heat pipe system with expanded heat exchange area Technical Field

[0001] This invention relates to a heat exchanger, and more particularly to a pulsating heat pipe heat exchanger. Background Technology

[0002] Heat pipe technology, a highly efficient phase change heat transfer element, originated in 1963 and was invented by George Grover at Los Alamos National Laboratory in the United States. It makes full use of the principle of heat conduction and the rapid heat transfer properties of phase change media to quickly transfer the heat of the heated object to the outside of the heat source through the heat pipe. Its thermal conductivity exceeds that of any known metal.

[0003] Pulsating heat pipes, also known as oscillating heat pipes, were proposed by Japanese scholar H. Akachi in the 1990s. Current pulsating heat pipes are simple in structure but complex in mechanism, representing a two-phase heat transfer device. They consist of a long capillary tube evacuated and then filled with liquid. If the capillary diameter is small enough, vapor and liquid plugs intermittently form inside. When one end of the pulsating heat pipe is heated, the liquid evaporates and vaporizes. The vapor flows to the other end under a small pressure difference, releasing heat and condensing back into liquid. Small tube diameter and repeated bending at the hot and cold ends are two fundamental conditions for the formation of a pulsating heat pipe. Heat is transferred through phase change and vapor-liquid pulsation. Compared to ordinary heat pipes, they have a simpler structure, do not require a wick, are unaffected by gravity, have a small diameter, and can be bent into any shape, offering good adaptability. Therefore, they have low manufacturing, operating, and maintenance costs. Due to their excellent performance, pulsating heat pipes are considered the most promising and likely heat transfer element for solving high heat flux heat dissipation problems in small spaces.

[0004] Existing pulsating heat pipes, such as those disclosed in CN104848718A and CN106643241A, generally suffer from an insufficient heat exchange area at the condenser end, resulting in poor heat dissipation. Therefore, improvements are needed to optimize their heat exchange performance. Summary of the Invention

[0005] In order to overcome the defects and shortcomings of the existing technology, the present invention provides a pulsating heat pipe system that expands the heat exchange area, thereby expanding the heat exchange area at the condenser end and improving the heat exchange effect.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A pulsating heat pipe system for expanding heat exchange area, the system comprising a pulsating heat pipe, the pulsating heat pipe including a lower bending structure and an upper bending structure, the lower bending structure including a vertically extending pipe and a connecting pipe connecting the upper and lower ends of an adjacent vertical pipe, the upper bending structure including a horizontally extending pipe and a connecting pipe connecting the left and right ends of an adjacent horizontal pipe, the upper bending structure and the lower bending structure forming a series loop structure through the connecting pipe, the pulsating heat pipe including an evaporating end and a condensing end, the evaporating end including the lower part of the lower bending structure, the condensing end including the upper part of the lower bending structure and the upper bending structure.

[0008] As an improvement, the lower part of the lower bending structure includes the lower part of the vertical pipe and a connecting pipe that connects to the lower end of the adjacent vertical pipe.

[0009] As an improvement, the upper part of the lower bending structure includes the upper part of the vertical tube and a connecting tube that connects to the upper end of the vertical tube.

[0010] As an improvement, the condenser end is located in the heat exchange box to transfer heat to the fluid in the heat exchange box.

[0011] As an improvement, the heat exchange box is divided into an independent upper box and a lower box by a partition. The upper box and the lower box have a fluid outlet and a fluid inlet, respectively. The upper bending structure is located in the upper box, and the upper part of the lower bending structure is located in the lower box.

[0012] As an improvement, a horizontal baffle is installed in the upper chamber, including a left baffle and a right baffle extending from the left and right walls of the chamber towards the center. The left and right baffles are spaced apart and positioned between adjacent horizontal pipes. The inlet and outlet of the upper chamber are configured such that the fluid in the upper chamber flows in the opposite direction to the fluid in the horizontal straight pipes. A vertical baffle is installed in the lower chamber, including a lower baffle extending upward from the lower wall of the chamber and an upper baffle extending downward from the partition. The lower and upper baffles are spaced apart and positioned between adjacent vertical pipes. The inlet and outlet of the lower chamber are configured such that the fluid in the lower chamber flows in the opposite direction to the fluid in the vertical pipes. The partition is a heat conductor, and the inlet and outlet of the upper and lower chambers are configured such that the fluid in the upper chamber flows in the opposite direction to the fluid in the lower chamber.

[0013] As an improvement, the inlet and outlet of the upper housing are located on the right and left sides of the upper housing, respectively.

[0014] As an improvement, the inlet and outlet of the lower housing are located on the left and right sides of the lower housing, respectively.

[0015] As an improvement, the volume of the upper box is 1.5-5 times that of the lower box.

[0016] As an improvement, the spacing between adjacent horizontal pipes in the upper chamber becomes smaller and smaller along the flow direction of the fluid inside the upper chamber.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. This invention expands the heat exchange area at the condenser end and improves the heat exchange effect by incorporating an upper bent structure at the condenser end. This upper bent structure includes a horizontally extending pipe and a connecting pipe that connects the left and right ends of adjacent horizontal pipes. Furthermore, because the upper bent pipe is a horizontally extending pipe, it flows perpendicularly to the lower bent vertical pipe, creating a cross-flow direction and further enhancing the heat exchange effect.

[0019] 2. By dividing the condenser end box into two parts, and having each part exchange heat with different fluids, the present invention can easily configure different fluid directions. For example, the heat exchange fluid in each box can be close to countercurrent heat exchange, which improves the heat exchange effect. At the same time, the fluids in the upper and lower boxes can also flow countercurrently for heat exchange. The countercurrent flow in three major directions further improves the heat exchange effect. Attached Figure Description

[0020] Figure 1 is a schematic diagram of the pulsating heat pipe structure of the present invention;

[0021] Figure 2 is a schematic diagram of the pulsating heat pipe system with heat exchange box of the present invention.

[0022] Figure 3 is a schematic diagram of the preferred fluid flow direction structure of the pulsating heat pipe system of the present invention. Detailed Implementation

[0023] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] Unless otherwise specified, in this article, " / " represents division, and "×" and "*" represent multiplication.

[0025] It should be noted that, unless otherwise specified, the directional terms "up," "down," "left," "right," "vertical," and "horizontal" in this invention do not represent actual locations, but are merely for ease of description. Specifically, "up," "down," "left," and "right" refer to the four positions of the pulsating heat pipe in Figure 1. "Vertical" and "horizontal" refer to the vertical and horizontal directions of the pulsating heat pipe in the front view angle of Figure 1, respectively, and are for descriptive convenience, not representing actual vertical and horizontal directions.

[0026] Figure 1-3 illustrates a pulsating heat pipe system for expanding heat exchange area. As shown in Figure 1, the system includes a pulsating heat pipe, which comprises a lower bend structure 1 and an upper bend structure 2. The lower bend structure 1 includes a vertical pipe 11 extending vertically and a connecting pipe 12 connecting the upper and lower ends of adjacent vertical pipes. The upper bend structure includes a horizontal pipe 21 extending horizontally and a connecting pipe 22 connecting the left and right ends of adjacent horizontal pipes. The upper and lower bend structures form a series loop structure through the connecting pipe 3. The pulsating heat pipe includes an evaporation end and a condensation end. The evaporation end includes the lower part of the lower bend structure, and the condensation end includes the upper part of the lower bend structure and the upper bend structure.

[0027] This invention expands the heat exchange area at the condenser end and improves the heat exchange effect by incorporating an upper bend structure. This upper bend structure includes a horizontally extending pipe and a connecting pipe linking the left and right ends of adjacent horizontal pipes. Furthermore, because the upper bend is a horizontally extending pipe, perpendicular to the flow direction of the lower bend vertical pipe, the fluid can form an intersecting structure with at least a portion of the condenser end during heat exchange, avoiding purely downstream flow and further enhancing the heat exchange effect.

[0028] As an improvement, the lower part of the lower bending structure 1 includes the lower part of the vertical pipe 11 and the connecting pipe 12 that connects to the lower end of the adjacent vertical pipe.

[0029] As an improvement, the upper part of the lower bending structure 1 includes the upper part of the vertical pipe 11 and the connecting pipe 12 that connects to the upper end of the vertical pipe.

[0030] The above arrangement allows the condenser end to include the upper connecting pipe with the lower bend structure and the upper straight pipe, expanding the heat exchange area. Moreover, since the upper bend is a horizontally extending pipe that flows perpendicularly to the lower bend vertical pipe, the fluid can form a cross structure with at least part of the condenser end during heat exchange, avoiding simple co-current flow and further improving the heat exchange effect.

[0031] As an improvement, the condenser end is located in the heat exchange box 3 to transfer heat to the fluid in the heat exchange box.

[0032] As an improvement, the heat exchange chamber 3 is divided into an independent upper chamber 31 and a lower chamber 32 by a partition 4. The upper and lower chambers each have a fluid outlet and a fluid inlet, respectively. The upper bent structure is located in the upper chamber, and the upper part of the lower bent structure is located in the lower chamber. By setting up two independent chambers, the upper and lower chambers can heat different fluids respectively, thereby outputting fluids at various temperatures to meet the needs of diverse output fluids and different users.

[0033] As an improvement, a horizontal baffle 311 is provided in the upper box (see Figure 2). The horizontal baffle includes a left baffle and a right baffle extending from the left and right walls of the box towards the center. The left and right baffles are spaced apart and are positioned between adjacent horizontal pipes. The inlet and outlet of the upper box are configured such that the fluid in the box flows in the opposite direction to the fluid in the horizontal straight pipes. A vertical baffle 321 is provided in the lower box. The vertical baffle includes a lower baffle extending upward from the lower wall of the box and an upper baffle extending downward from the partition. The lower and upper baffles are spaced apart and are positioned between adjacent vertical pipes. The inlet and outlet of the lower box are configured such that the fluid in the lower box flows in the opposite direction to the fluid in the vertical pipes. The partition is a heat conductor, and the inlet and outlet of the upper box and the lower box are configured such that the fluid in the upper box flows in the opposite direction to the fluid in the lower box.

[0034] This invention divides the condenser end chamber into two parts, with each part exchanging heat with a different fluid. This allows for easy configuration of different fluid directions, such as making the heat exchange fluid in each chamber nearly counter-current, thus improving the heat exchange effect. At the same time, the fluids in the upper and lower chambers can also flow counter-currently for heat exchange. The counter-current flow in three major directions further enhances the heat exchange effect.

[0035] It should be noted that the countercurrent flow of fluids in the upper and lower chambers mentioned above is a countercurrent flow in the general direction, as shown in Figure 3. The two fluids flow from left to right and from right to left, respectively.

[0036] As an improvement, as shown in Figure 3, when the number of horizontal baffles is even, the inlet and outlet of the upper housing are respectively located on both sides of the upper housing, such as the right and left sides in Figure 1. Preferably, they are located on the upper part of the left side and the lower part of the right side. When the number of horizontal baffles is odd, the inlet and outlet of the upper housing are respectively located on the same side of the upper housing, such as simultaneously located on the left and right sides.

[0037] As an improvement, as shown in Figure 3, the inlet and outlet of the lower box are located on the left and right sides of the lower box, respectively.

[0038] As an improvement, the flow direction of the fluid inside the heat pipe is from bottom to top in the leftmost connecting pipe 3.

[0039] The above setup can create a triple counter-current flow, thus achieving the best heat exchange effect.

[0040] As an improvement, the volume of the upper box is 1.5-5 times that of the lower box.

[0041] As an improvement, the spacing between adjacent horizontal pipes in the upper chamber gradually decreases along the flow direction of the fluid, then increases again after a certain point. This is because numerical simulations and experiments revealed that under counter-current heat transfer conditions with horizontal baffles, the heat transfer effect is best and the temperature difference is greatest near the inlet and outlet, while the heat transfer effect deteriorates towards the middle. Therefore, it is necessary to compensate for the heat transfer in the middle to achieve the best overall heat transfer effect. Thus, the variation in the horizontal pipe spacing was implemented to enhance heat transfer in the middle section.

[0042] As an improvement, along the flow direction of the fluid in the upper chamber, the spacing between adjacent horizontal pipes in the upper chamber gradually increases in magnitude, and then gradually increases in magnitude again. This variation in magnitude can further improve the heat exchange effect.

[0043] As an improvement, a certain position is set in the middle of the upper box in the vertical direction.

[0044] As an improvement, the baffle acts as a heat conductor, allowing heat exchange between the fluids in the upper and lower flow channels. By installing the heat-conducting baffle, heat exchange between the fluids in the upper and lower flow channels can be achieved, resulting in heat complementarity between the two channels. This allows the higher-temperature fluid in one channel to transfer heat to the lower-temperature fluid, which then cools down and absorbs heat from the heat pipe, maximizing heat exchange. Through the complementary heat conduction of the baffle, optimal heat exchange performance can be achieved regardless of whether the flow is co-current or counter-current.

[0045] As an improvement, the thermal conductivity of the partition varies at different locations, gradually decreasing from the center to the left and right sides. When the fluid in the upper and lower chambers flows in opposite directions, the inlet and outlet of the chamber are located on the left and right sides respectively. At this time, the temperature difference between the two is the largest, and the heat exchange effect is the best. This is because by increasing the thermal conductivity of the middle position, the heat exchange effect is increased, so that the overall heat exchange is balanced, thus achieving the best heat exchange effect.

[0046] As an improvement, the thermal conductivity decreases at an increasingly greater rate from the center of the partition towards the left and right sides. This design further enhances the heat exchange effect, achieving a more balanced overall heat exchange and ultimately resulting in optimal heat exchange performance.

[0047] While the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A pulsating heat pipe system for expanding heat exchange area, the system comprising a pulsating heat pipe, the pulsating heat pipe comprising a lower bending structure and an upper bending structure, the lower bending structure comprising a vertically extending vertical pipe and a connecting pipe connecting the upper and lower ends of an adjacent vertical pipe, the upper bending structure comprising a horizontally extending horizontal pipe and a connecting pipe connecting the left and right ends of an adjacent horizontal pipe, the upper bending structure and the lower bending structure forming a series loop structure through the leftmost and rightmost connecting pipes, the pulsating heat pipe comprising an evaporating end and a condensing end, the evaporating end comprising the lower part of the lower bending structure, the condensing end comprising the upper part of the lower bending structure and the upper bending structure; the lower part of the lower bending structure comprising the lower part of a vertical pipe and a connecting pipe connecting the lower end of an adjacent vertical pipe; the upper part of the lower bending structure comprising the upper part of a vertical pipe and a connecting pipe connecting the upper end of the vertical pipe; the condensing end is disposed in a heat exchange chamber, transferring heat to the fluid in the heat exchange chamber; the heat exchange chamber is divided into an independent upper chamber and a lower chamber by a partition, the upper chamber and the lower chamber... The housing has a fluid outlet and a fluid inlet. The upper bent structure is located in the upper housing, and the upper part of the lower bent structure is located in the lower housing. Horizontal baffles are installed in the upper housing, including a left baffle and a right baffle extending from the left and right walls of the housing towards the center. The left and right baffles are spaced apart and positioned between adjacent horizontal pipes. The inlet and outlet of the upper housing are configured such that the fluid flow direction inside the housing is opposite to that of the fluid in the horizontal straight pipes. Vertical baffles are installed in the lower housing, including a lower baffle extending upward from the lower wall of the housing and an upper baffle extending downward from the partition. The lower and upper baffles are spaced apart and positioned between adjacent vertical pipes. The inlet and outlet of the lower housing are configured such that the fluid flow direction inside the lower housing is opposite to that of the fluid in the vertical pipes. The partition is a heat conductor, and the inlet and outlet of the upper and lower housings are configured such that the fluid flow direction inside the upper housing is opposite to that of the fluid in the lower housing.

2. The pulsating heat pipe system as described in claim 1, characterized in that, The inlet and outlet of the upper box are located on the right and left sides of the upper box, respectively.

3. The pulsating heat pipe system as described in claim 1, characterized in that, The inlet and outlet of the lower housing are located on the left and right sides of the lower housing, respectively.

4. The pulsating heat pipe system as described in claim 1, characterized in that, The volume of the upper box is 1.5 to 5 times that of the lower box.

5. The pulsating heat pipe system as described in claim 1, characterized in that, Along the flow direction of the fluid in the upper chamber, the distance between adjacent horizontal pipes in the upper chamber becomes smaller and smaller.

Images