Heat transfer analysis of vapor chamber heat pipe for high power LED package

The appearance of high power LED has put forward higher requirements for thermal management. The micro heat pipe (MHP) has high heat transfer ability and plays an important role in high power LED and other high heat flux device cooling. In this paper, we designed and fabricated a micro heat pipe with fluoroalkyl silane (FAS) surface modified glass cover. The contact angle of the working area of glass cover reached 95.49° and made working fluid drops fall back to micro groove of silicon substrate more quickly. Thus the new glass cover can speed up the circulation of working fluid and enhance the heat transfer. The experimental results also proved that hydrophobic glass cover has a better heat transfer capability. Besides, this novel MHP reached the stable working status faster. When the input heat power was 10 W, the balance temperature of MHP with hydrophobic glass cover was 22 oC lower than traditional MHP, while the balance time is 58 seconds less. The work presented in this paper provides a new direction for optimize the MHP, not only the wick structure in substrate, but also the wettability of cover plate.

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Heat Transfer Analysis of Heat Sink Modules for High Power LED Equipment

Journal of Enhanced Heat Transfer ◽

10.1615/jenhheattransf.2020036197 ◽

2020 ◽

Author(s):

Hai-Ping Hu ◽

Rong-Hua Yeh

Keyword(s):

Heat Transfer ◽

High Power ◽

Heat Sink ◽

Heat Transfer Analysis ◽

High Power Led

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Sodium-Potassium Alloy Heat Pipe under Geyser Boiling Experimental Study: Heat Transfer Analysis

Energies ◽

10.3390/en14227582 ◽

2021 ◽

Vol 14 (22) ◽

pp. 7582

Author(s):

Hongzhe Zhang ◽

Fang Ye ◽

Hang Guo ◽

Xiaoke Yan

Keyword(s):

Heat Transfer ◽

Heat Pipe ◽

Heating Power ◽

Heat Transfer Analysis ◽

Working Fluid ◽

Condenser Section ◽

Sodium Potassium ◽

Alloy Heat ◽

Convection Cooling ◽

Boiling Mode

In the geyser boiling mode, the working fluid state is divided into a boiling process and a quiet process, and the sodium-potassium (Na-K) alloy heat pipe can discontinuously transfer heat at each boiling. The overheating of the liquid working fluid at the bottom causes short-term boiling and forms slug bubble, the strong condensing ability quickly conducts heat from the evaporator section. And geyser boiling can occur before the working fluid forms continuous flow, so it transfers more heat at lower temperatures than natural convection cooling. In this study, the heat transfer process of a Na-K alloy heat pipe with forced convection cooling under different heating power was experimental studied. The geyser boiling mode can make the Na-K alloy heat pipe work below 650 °C and reduce the start-up time. In the process of geyser boiling, the heat transfer quantity was increased by the boiling frequency and the amount of vapor produced in a single boiling. The boiling temperature had no obvious change with the increased of heating power, and the condenser section temperature increased with the heating power.

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