Sawtooth gradual change type pulsating heat pipe
By introducing a serrated gradient structure design into the pulsating heat pipe, the problems of difficult start-up and insufficient heat transfer of existing pulsating heat pipes under different operating conditions are solved, achieving more efficient heat transfer and improved stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2026-04-17
AI Technical Summary
Existing pulsed heat pipes suffer from problems such as difficulty in starting up, insufficient heat transfer performance, and poor system stability under different operating conditions. Traditional pipe structures with fixed diameters cannot meet the needs of heat pipe performance optimization.
The design adopts a serrated gradient structure, with both the evaporation and condensation units including serrated gradient tube sections. The serrated gradient tube sections gradually expand or contract along the axial direction, increasing the effective heat exchange area, improving fluidity and circulation stability, and optimizing the flow channel structure through the serrated shape design.
It significantly improves the heat transfer efficiency of heat pipes, enhances fluidity and circulation stability, reduces flow resistance, and promotes faster heat transfer and efficient system operation.
Smart Images
Figure CN224136444U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of heat exchange technology, specifically to a serrated gradient pulsating heat pipe. Background Technology
[0002] Pulsating heat pipes are thermal management devices that feature self-starting, self-regulation, and high heat transfer efficiency, such as... Figure 1 As shown, it mainly consists of an evaporation section, a condensation section, and an adiabatic section. Due to its simple structure, low thermal resistance, and strong adaptability to the operating environment, the pulsating heat pipe has broad application prospects in fields such as electronic equipment cooling, fuel cell heat dissipation, and solar energy utilization. The pulsating heat pipe achieves efficient heat transfer through the circulating evaporation and condensation process of the working liquid within the closed tube between the evaporation and condensation units.
[0003] While existing pulsating heat pipe designs have achieved some application in many fields, they still suffer from problems such as difficult start-up, insufficient heat transfer performance, and poor system stability. In particular, the performance of pulsating heat pipes is affected by multiple factors, including the internal flow structure, the type of working fluid, and the pipe geometry, under different operating conditions. Traditional pulsating heat pipes mostly use a fixed-diameter pipe structure, but in different applications, a fixed-diameter pipe structure cannot fully meet the requirements for optimizing heat pipe performance. Therefore, optimizing the structural design of pulsating heat pipes, especially by changing the internal geometry of the pipe to promote more efficient flow and heat transfer, has become an important direction for improving their performance.
[0004] In recent years, some studies have proposed improving heat exchange efficiency by introducing special structural designs, such as microchannels, grooves, or other shaped flow channels, inside pulsating heat pipes. However, these structural designs typically present significant manufacturing challenges and offer limited performance improvements, and their specific impact on flow and heat transfer within the heat pipe has not yet been fully and systematically analyzed and verified.
[0005] Therefore, there is an urgent need for a new pulsating heat pipe structure design that can further optimize the heat transfer efficiency and improve the operational stability of the heat pipe while ensuring manufacturing feasibility. Utility Model Content
[0006] In view of the technical problems existing in the prior art, the purpose of this utility model is to provide a serrated gradient pulsating heat pipe that can significantly improve heat transfer efficiency.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: a serrated gradient pulsating heat pipe, comprising a heat pipe body, the heat pipe body comprising an evaporation unit, a condensation unit and an insulation unit, the insulation unit being located between the evaporation unit and the condensation unit; both the evaporation unit and the condensation unit include serrated gradient tube sections, the edges of the axial cross-section of the serrated gradient tube sections are serrated, the serrated gradient tube sections as a whole have an axially gradually expanding structure, and the expansion direction is towards the insulation unit.
[0008] With this structure, the evaporator unit faces downwards and the condenser unit faces upwards during use. The serrated design increases the effective heat exchange area. The design of gradually expanding towards the adiabatic unit, where the serrated tapered tube section of the evaporator unit gradually expands upwards and the serrated tapered tube section of the condenser unit gradually narrows upwards, allows the evaporator unit to gradually increase the flow channel width. During the evaporation and upward diffusion of the working fluid, the local flow resistance of the gas is reduced, and the liquid can gradually accumulate in the condenser unit, avoiding the formation of excessive liquid film due to liquid stagnation. This improves circulation stability and enhances heat transfer efficiency.
[0009] As a preferred embodiment, the end of the serrated tapered pipe section closest to the insulation unit is connected to a first pipe section, and the end of the serrated tapered pipe section furthest from the insulation unit is connected to a second pipe section. The first and second pipe sections are constant inner diameter pipe structures, with the inner diameter of the first pipe section being larger than that of the second pipe section.
[0010] As a preferred option, the inner diameter ratio of the first pipe section and the second pipe section is 5:4.
[0011] As a preferred option, the heat pipe body is serpentine and connected end to end. Both the evaporation unit and the condensation unit are composed of multiple U-shaped tube structures. Each U-shaped tube structure contains two serrated tapered tube sections, two first tube sections and one second tube section. The first tube section is a straight tube with a constant inner diameter, and the second tube section is a 180° bend.
[0012] As a preferred embodiment, the insulation unit includes multiple insulation pipe sections with constant inner diameter, one end of which is connected to the first pipe section of the evaporation unit, and the other end of which is connected to the first pipe section of the condensation unit.
[0013] As a preferred option, the ratio of the total pipe length of the evaporation unit to that of the condensation unit is 1:(0.6~1).
[0014] As a preferred embodiment, in the serrated tapered tube section, the cross-section of a single serration is an isosceles right triangle, and the length and height of the base of the serration gradually increase along the direction toward the insulation unit.
[0015] As a preferred option, the heat pipe body is evacuated and filled with working fluid.
[0016] As a preferred option, the heat pipe body is installed vertically, with the condensing unit located above the evaporating unit.
[0017] As a preferred embodiment, a water-cooled heat dissipation device is provided on the outside of the condensing unit, which absorbs the heat of the condensing unit through cooling water.
[0018] In summary, this utility model has the following advantages:
[0019] 1. The serrated design effectively increases the effective heat exchange area of the evaporation unit. During liquid evaporation, a larger heat exchange area helps improve the heat load carrying capacity of the heat pipe, thereby enhancing the overall heat transfer efficiency of the heat pipe.
[0020] 2. The serrated, gradually expanding structure improves the flowability of the working fluid within the evaporation unit by increasing the degree of turbulence in the local fluid. The generation of turbulence helps to promote more uniform heat transfer, reduce the residence time of the liquid during the heat transfer process, and increase the heat exchange rate.
[0021] 3. The serrated gradually expanding structure of the evaporation unit can gradually increase the flow channel width, reduce local flow resistance, avoid the increase in flow resistance caused by the rapid change of the flow channel in the traditional straight pipe gradual structure, and reduce the energy loss of the system.
[0022] 4. The serrated tapered structure allows the liquid to gradually accumulate in the condensation unit and guides the liquid to flow smoothly through the tapered structure, avoiding the formation of too much liquid film due to liquid stagnation, which would lead to insufficient condensation.
[0023] 5. The addition of a serrated structure effectively improves the problem of insufficient driving force and promotes rapid return of the working fluid, thereby optimizing the flow pattern distribution within the pulsating heat pipe.
[0024] 6. The sawtooth structure design has strong flexibility. The number, size and gradient of the sawtooth can be adjusted according to actual needs to adapt to different heat load requirements and operating environments. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of a pulsed heat pipe structure in the prior art.
[0026] Figure 2 This is a schematic diagram of a serrated, gradually changing pulsating heat pipe.
[0027] Figure 3 This is a three-dimensional view of the sawtooth-gradient section of a sawtooth-gradient pulsating heat pipe.
[0028] 1 is the condensation unit; 2 is the insulation unit; 3 is the evaporation unit; 4 is the first pipe section; 5 is the serrated tapered pipe section; and 6 is the second pipe section. Detailed Implementation
[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0030] Example 1
[0031] like Figures 2-3 As shown, a serrated gradient pulsating heat pipe includes a heat pipe body, which includes an evaporation unit, a condensation unit, and an insulation unit. The insulation unit is located between the evaporation unit and the condensation unit. Both the evaporation unit and the condensation unit include serrated gradient tube sections. The edges of the axial cross-section of the serrated gradient tube sections are serrated. The serrated gradient tube sections have an overall axially expanding structure, and the expansion direction is towards the insulation unit.
[0032] The first pipe section is connected to the end of the serrated tapered pipe section closest to the insulation unit, and the second pipe section is connected to the end of the serrated tapered pipe section furthest from the insulation unit. The first and second pipe sections are constant inner diameter pipe structures, and the inner diameter of the first pipe section is larger than that of the second pipe section.
[0033] The inner diameter ratio of the first pipe section to the second pipe section is 5:4.
[0034] The heat pipe body is serpentine and connected end to end. Both the evaporation unit and the condensation unit are composed of multiple U-shaped tube structures. Each U-shaped tube structure contains two serrated tapered tube sections, two first tube sections and one second tube section. The first tube section is a straight tube with a constant inner diameter, and the second tube section is a 180° bend.
[0035] The insulation unit consists of multiple insulation pipe sections with constant inner diameter. One end of each insulation pipe section is connected to the first pipe section of the evaporation unit, and the other end is connected to the first pipe section of the condensation unit.
[0036] The ratio of the total tube length of the evaporation unit to that of the condensation unit is 1:(0.6~1).
[0037] In the serrated tapered tube section, the cross-section of a single serration is an isosceles right triangle, and the length and height of the base of the serration gradually increase along the direction toward the insulation unit.
[0038] The heat pipe body is evacuated and filled with working fluid. The heat pipe body is a sealed pipe structure, and water is filled inside as the working fluid.
[0039] The pipe diameters of the above sections are calculated based on the surface tension of different working fluids. In this embodiment, the pipe wall is made of copper. The inner diameter of the first pipe section is 5mm, and the inner diameter of the second pipe section is 4mm. The total length of the condensation unit is 80mm, the total length of the evaporation unit is 100mm, and the total length of the insulation unit is 40mm.
[0040] The heat pipe body is installed vertically, and the condensing unit is located above the evaporating unit.
[0041] A water-cooled heat dissipation device is installed on the outside of the condensing unit, which absorbs the heat of the condensing unit through cooling water.
[0042] The start-up process and working principle of the serrated gradient pulsating heat pipe are as follows:
[0043] Step 1: Fill the heat pipe body, which has been evacuated, with some working fluid. In this embodiment, water is selected as the working fluid. The working fluid forms intermittent gas-liquid plugs under the action of surface tension.
[0044] Step Two: As Figure 2 As shown, the direction of the arrow indicates the direction of heat transfer. A high-efficiency heat source (such as resistance wire heating) is used to heat the outside of the evaporation unit, so that the working fluid is heated and evaporated into steam, increasing the temperature and pressure inside the evaporation unit. This process further increases the heat exchange area through the sawtooth gradually expanding surface design, resulting in higher evaporation efficiency, thereby increasing the steam pressure difference, promoting the phase change process of the working fluid, and stabilizing the formation of gas-liquid two-phase flow.
[0045] Step 3: An existing water-cooling system is used outside the condenser unit, where cooling water absorbs the heat from the steam in the condenser unit. The entire process increases the gas-liquid contact area in the evaporator unit through a serrated structure, and also increases the condensation area in the condenser unit, allowing more liquid to condense and quickly flow back to the evaporator unit, forming a faster circulation.
[0046] Step 4: During further heating, the addition of the serrated structure to the evaporation unit increases the area for bubble formation, resulting in a more uniform distribution of the bubbly flow. This improves the heat transfer efficiency of the heat pipe and enhances system stability. Compared to traditional pulsating heat pipes, the serrated gradient structure enhances overall heat conduction performance by expanding the bubbly flow formation area, ensuring efficient operation of the heat pipe under various operating conditions.
[0047] Step 5: When the working fluid passes through the serrated gradient structure, the disturbance of the working fluid is enhanced, effectively reducing surface tension and capillary hysteresis resistance, solving the problem of insufficient driving force of conventional heat pipes, and thus significantly accelerating the start-up speed of the heat pipe.
[0048] The above embodiments are preferred embodiments of the utility model, but the implementation of the utility model is not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the utility model shall be considered equivalent substitutions and shall be included within the protection scope of the utility model.
Claims
1. A saw tooth gradient pulsating heat pipe characterized by: It includes the heat pipe body, which comprises an evaporation unit, a condensation unit, and an insulation unit, with the insulation unit located between the evaporation unit and the condensation unit. Both the evaporation unit and the condensation unit include a serrated tapered tube section. The edge of the axial section of the serrated tapered tube section is serrated. The serrated tapered tube section as a whole has an axially expanding structure, and the expansion direction is towards the insulation unit.
2. The sawing-graded pulsating heat pipe according to claim 1, characterized by: The first pipe section is connected to the end of the serrated tapered pipe section closest to the insulation unit, and the second pipe section is connected to the end of the serrated tapered pipe section furthest from the insulation unit. The first and second pipe sections are constant inner diameter pipe structures, with the inner diameter of the first pipe section being larger than that of the second pipe section.
3. The saw tooth gradient pulsating heat pipe according to claim 2, wherein: The inner diameter ratio of the first pipe section to the second pipe section is 5:
4.
4. The saw tooth gradient pulsating heat pipe according to claim 2, wherein: The heat pipe body is serpentine and connected end to end. Both the evaporation unit and the condensation unit are composed of multiple U-shaped tube structures. Each U-shaped tube structure contains two serrated tapered tube sections, two first tube sections and one second tube section. The first tube section is a straight tube with a constant inner diameter, and the second tube section is a 180° bend.
5. The sawing-graded pulsating heat pipe according to claim 4, characterized by: The insulation unit consists of multiple insulation pipe sections with constant inner diameter. One end of each insulation pipe section is connected to the first pipe section of the evaporation unit, and the other end is connected to the first pipe section of the condensation unit.
6. The sawing-graded pulsating heat pipe according to claim 1, wherein: The ratio of the total tube length of the evaporation unit to that of the condensation unit is 1:(0.6~1).
7. The saw tooth gradient pulsating heat pipe according to claim 1, wherein: In the serrated tapered tube section, the cross-section of a single serration is an isosceles right triangle, and the length and height of the base of the serration gradually increase along the direction toward the insulation unit.
8. The sawing-graded pulsating heat pipe according to claim 1, wherein: The heat pipe body is evacuated and filled with working fluid.
9. The sawing-graded pulsating heat pipe according to claim 1, wherein: The heat pipe body is installed vertically, and the condensing unit is located above the evaporating unit.
10. The saw tooth gradient pulsating heat pipe according to claim 1, wherein: A water-cooled heat dissipation device is installed on the outside of the condensing unit, which absorbs heat from the condensing unit through cooling water.