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CN-122028374-A - Spray enhanced two-phase evaporation type flat loop heat pipe evaporator and heat dissipation system

CN122028374ACN 122028374 ACN122028374 ACN 122028374ACN-122028374-A

Abstract

The invention discloses a spray enhanced two-phase evaporation type flat loop heat pipe evaporator and a heat dissipation system, and relates to the technical field of heat management of high heat flux electronic devices. The evaporator comprises an evaporator substrate, a double-layer capillary core, a liquid baffle plate and an upper cover plate, wherein the double-layer capillary core is formed by sequentially covering a fine pore capillary core and a coarse pore distribution layer, the liquid baffle plate is provided with uniformly distributed through holes, the upper cover plate is jointly sealed to form a steam cavity, an active spraying device is arranged to actively spray condensate into a liquid converging groove area, a stable liquid film is formed by the distribution of the double-layer capillary core, steam generated by boiling is guided to a single-end steam converging area through the low resistance of the steam groove network, and gas-liquid separation is realized through the liquid baffle plate to prevent high-speed steam entrainment. The invention ensures that the evaporation area stably maintains the rich liquid nucleate boiling state, effectively inhibits capillary core drying, realizes stable heat dissipation of extremely high heat flux density above 300W/cm < 2 >, and is suitable for heat management of high-power chips such as GPU, AI accelerators and the like.

Inventors

  • PAN JINYI
  • Pan Zhuochen
  • PAN JIANWU

Assignees

  • 上海福宁保远科技有限公司

Dates

Publication Date
20260512
Application Date
20260317

Claims (10)

  1. 1. The spray enhanced two-phase evaporation type flat loop heat pipe evaporator is characterized by comprising an evaporator substrate (100), a capillary core layer, a liquid baffle plate (106), an upper cover plate (109) and a spray device; The evaporator comprises an evaporator substrate (100), a heat source (001), a liquid converging groove (102) and a steam groove network, wherein the outer side of the evaporator substrate (100) is thermally coupled with the heat source (001), the inner side of the evaporator substrate is provided with the liquid converging groove (102) at a position corresponding to a high heat flux density region of the heat source (001), and the evaporator substrate (100) is provided with the steam groove network at a position positioned at the periphery of the liquid converging groove (102) and used for guiding steam generated around the liquid converging groove (102) to a steam converging region (107); the capillary core layer is covered above the evaporator substrate (100), the liquid baffle (106) is arranged above the capillary core layer in parallel, the upper cover plate (109) is covered above the liquid baffle (106) and is in sealing connection with the peripheral edge of the evaporator substrate (100) to form a closed steam cavity (110), and the steam converging area (107) is positioned at one end of the steam cavity (110); The spraying device comprises a spraying head (111) arranged in the steam cavity (110), and the spraying head (111) is used for actively spraying condensate into the liquid converging groove (102).
  2. 2. The spray enhanced two-phase evaporation type flat loop heat pipe evaporator as claimed in claim 1, wherein the depth of the liquid convergence groove (102) is 0.25-0.50mm, the edge of the liquid convergence groove (102) is provided with a slope (114) and makes a rounded transition, and an annular shallow vapor collecting groove (113) is arranged at the periphery of the slope (114) and is used as a gas-liquid buffer area.
  3. 3. A spray enhanced two-phase evaporative flat loop heat pipe evaporator according to claim 2, wherein said vapor tank network comprises a plurality of main vapor tanks (105) and a plurality of branch vapor tanks (112), said main vapor tanks (105) converging in a fan shape from the periphery of said liquid converging recess (102) toward said vapor converging region (107), the cross-sectional area of said main vapor tanks (105) monotonically increasing along the vapor flow direction for accommodating vapor flow accumulation and reducing flow pressure drop; The branch steam grooves (112) are distributed around the annular shallow steam collecting groove (113) and are used for communicating the liquid converging groove (102) with the main steam groove (105), and steam generated around the annular shallow steam collecting groove (113) is closely led into the main steam groove (105), and the steam flows to the steam converging area (107) along the low resistance of the main steam groove (105).
  4. 4. A spray enhanced two-phase evaporative flat loop heat pipe evaporator as set forth in claim 3 wherein said primary vapor tank (105) has a width of 0.1-0.5mm and a depth of 0.30-0.55mm.
  5. 5. A spray enhanced two-phase evaporation type flat loop heat pipe evaporator as claimed in claim 1, wherein said wick layer comprises a fine pore wick layer (103) and a coarse pore distribution layer (104) which are arranged in sequence from bottom to top; The thickness of the fine pore capillary core layer (103) in the area corresponding to the liquid converging groove (102) is smaller than that of the peripheral area, the pore diameter of the fine pore capillary core layer (103) is 10-30 mu m, the thickness of the fine pore capillary core layer is 0.3-0.8mm, the pore diameter of the coarse pore distribution layer (104) is 50-100 mu m, and the thickness of the coarse pore distribution layer is 0.5-2mm.
  6. 6. The spray enhanced two-phase evaporation type flat loop heat pipe evaporator as claimed in claim 1, wherein the liquid baffle (106) covers the whole evaporation area, is used for isolating the vapor chamber (110) above the liquid baffle from the liquid area below the liquid baffle, has a thickness of 0.2-0.4mm, is uniformly distributed with through holes on the surface, and has an aperture ratio of 20% -40%.
  7. 7. A spray enhanced two-phase evaporative flat loop heat pipe evaporator, as set forth in claim 1, wherein the vapor chamber (110) has a height of 1.2-1.8mm in the evaporation zone and is raised locally to 2.5-3.0mm in the vapor convergence zone (107) to form a single ended vapor collection chamber structure.
  8. 8. A spray enhanced two-phase evaporation type flat loop heat pipe evaporator as claimed in claim 1, wherein the total opening area of said spray header (111) is configured to be a main throttle element for controlling the spray flow rate, and the spray flow rate is configured to be 1.2-3 times the theoretical lower limit flow rate, so as to maintain the evaporation area in a liquid-rich nucleate boiling state and inhibit capillary drying.
  9. 9. The spray enhanced two-phase evaporation type flat loop heat pipe evaporator according to claim 8, wherein the pressure drop of the spray header at the target flow is 10-40kPa, and the spray header is provided with spray holes arranged in an array, and the number of the spray holes is 15-25.
  10. 10. A spray enhanced two-phase evaporation type flat loop heat pipe heat dissipation system, comprising the evaporator as claimed in any one of claims 1-9, and further comprising a condenser (200), a steam pipe (203) and a return pipe (108), wherein the steam pipe (203) is used for connecting the evaporator with the condenser (200), the return pipe (108) is used for connecting the condenser (200) with a spray device, the spray device is driven by a liquid driving magnetic pump (800) arranged on a return liquid path, and the liquid driving magnetic pump (800) is connected with a magnetic pump fluid driving pipe (900).

Description

Spray enhanced two-phase evaporation type flat loop heat pipe evaporator and heat dissipation system Technical Field The invention relates to the technical field of thermal management of high-heat-flux electronic devices, in particular to a spray enhanced two-phase evaporation type flat loop heat pipe evaporator and a heat dissipation system. Background With the rapid development of fields such as artificial intelligence, high-performance computing, data centers, etc., the integration level and power consumption density of electronic chips have been continuously increased. At present, the power consumption of a single chip breaks through 2000W, the local heat flux density exceeds 300W/cm < 2 >, and extremely high requirements are put on a thermal management system. Traditional air cooling and single-phase liquid cooling have difficulty in meeting the heat dissipation requirements of such high heat flux scenes due to limited heat dissipation capacity. The two-phase heat dissipation technology utilizes the phase change latent heat of the working medium and has the remarkable advantage of high-efficiency heat transfer. The loop heat pipe is used as a passive two-phase heat transfer device, and the loop heat pipe drives working medium to circulate by virtue of capillary force generated by a capillary core, so that the loop heat pipe has the advantages of no moving parts, long heat transfer distance, flexible arrangement and the like, and gradually becomes a research hot spot for heat management of high heat flux devices. However, conventional flat Loop Heat Pipes (LHPs) suffer from the following problems under high heat flux conditions: (1) The capillary force is limited, and the evaporator is easy to dry due to insufficient liquid backflow; (2) The starting process is unstable, and the superheat degree needs to be accurately controlled; (3) Is sensitive to gravity, and the backflow resistance is increased under the vertical or complex specific installation posture of the high-density rack of the data center, so that the performance is easy to be limited to be reduced. In order to solve the above problems, some solutions in the prior art have proposed using pump driving to assist in backflow to enhance the liquid circulation capability, but the focus is mostly on peripheral driving mode, and the optimization of the gas-liquid separation and distribution structure inside the evaporator is neglected. In fact, the evaporator is used as a core component of the loop heat pipe, and the internal structural design of the evaporator directly determines the uniformity of liquid film distribution, the stability of evaporation and the smoothness of steam discharge. If the collaborative design of spraying active liquid supply, uniform liquid film formation and low-resistance steam guiding out can be realized in the evaporator, the operation stability and heat dissipation limit of the system under high heat flow density can be expected to be obviously improved. Therefore, there is a need to design a new evaporator structure that can maintain stable nucleate boiling at high heat flux, prevent drying, and achieve very low flow resistance vapor discharge. Disclosure of Invention The invention mainly aims to provide a spray enhanced two-phase evaporation type flat loop heat pipe evaporator and a heat dissipation system, which are used for overcoming the problems in the prior art. In order to solve the technical problems, the invention adopts the following technical scheme: A spray enhanced two-phase evaporation type flat loop heat pipe evaporator comprises an evaporator substrate, a capillary core layer, a liquid baffle, an upper cover plate and a spray device; The evaporator comprises an evaporator substrate, a heat source, a liquid converging groove, a steam groove network, a steam flow channel and a steam flow channel, wherein the outer side of the evaporator substrate is in thermal coupling with the heat source, the inner side of the evaporator substrate is provided with the liquid converging groove at a position corresponding to a high heat flow density region of the heat source, and the evaporator substrate is provided with the steam groove network at a position positioned at the periphery of the liquid converging groove and used for guiding steam generated around the liquid converging groove to a steam converging region; The capillary core layer is covered above the evaporator substrate, the liquid baffle is arranged above the capillary core layer in parallel, the upper cover plate is covered above the liquid baffle and is in sealing connection with the peripheral edge of the evaporator substrate to form a closed steam cavity, and the steam converging area is positioned at one end of the steam cavity; The spraying device comprises a spraying head arranged in the steam cavity, and the spraying head is used for actively spraying condensate into the liquid converging groove. Further, the depth of the liquid converging groove