Thermal performance of flat micro heat pipe with converging microchannels

Micro heat pipe is a two-phase heat transfer device offering effective high heat-flux removal in electronics cooling. Essentially, micro heat pipe relies on the phase change processes, namely evaporation and condensation, and the circulation of working fluid to function as heat transfer equipment. The vast applications of micro heat pipe in portable appliances necessitate its functionality under different orientations with respect to gravity. Therefore, its thermal performance is strongly related to its orientation. By incorporating solid wall conduction, together with the continuity, momentum, and energy equations of the working fluid, a mathematical model is developed to investigate the heat and fluid flow characteristics of inclined micro heat pipes. We investigate both the favorable and adverse effects of gravity on the circulation rate which is intimately related to the thermal performance of micro heat pipes. The effects of gravity, through the angle of inclination, on the circulation strength and heat transport capacity are analysed. This study serves as a useful analytical tool in the micro heat pipe design and performance analysis, associated with different inclinations and operating conditions.

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Experimental study on the thermal performance of a new type of thermal energy storage based on flat micro-heat pipe array

Energy Conversion and Management ◽

10.1016/j.enconman.2016.01.039 ◽

2016 ◽

Vol 112 ◽

pp. 395-403 ◽

Cited By ~ 18

Author(s):

Feng-fei Li ◽

Yan-hua Diao ◽

Yao-hua Zhao ◽

Ting-ting Zhu ◽

Jing Liu

Keyword(s):

Experimental Study ◽

Energy Storage ◽

Heat Pipe ◽

Thermal Performance ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Micro Heat Pipe ◽

New Type

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Thermal Performance of a Low-Temperature Heat Exchanger Using a Micro Heat Pipe Array

Energies ◽

10.3390/en12040675 ◽

2019 ◽

Vol 12 (4) ◽

pp. 675 ◽

Cited By ~ 1

Author(s):

Jingang Yang ◽

Yaohua Zhao ◽

Aoxue Chen ◽

Zhenhua Quan

Keyword(s):

Heat Transfer ◽

Heat Exchanger ◽

Heat Exchange ◽

Low Temperature ◽

Heat Pipe ◽

Thermal Performance ◽

Flue Gas ◽

Thermal Efficiency ◽

Heat Exchangers ◽

Micro Heat Pipe

Domestic heat exchangers, even though widely used in industry, are not adequate for studies on low-temperature flue-gas use technologies. Despite spite their limitations, very few theoretical models have been investigated based on practical applications. Moreover, most of the existing studies on heat exchangers have focused particularly on one-dimensional and two-dimensional heat transfer models, while limited studies focus on three-dimensional ones. Therefore, this study aims at investigating the thermal performance of a low-temperature flue-gas heat recovery unit in the cold regions. Specifically, this study was conducted in the context of Changchun of Jilin Province, China, a city with the mean ambient temperature of −14 °C and mean diurnal temperature of −10 °C during winter. Experimental results showed that the thermal efficiency of the heat exchanger was higher than 60%. Through assessing the heat exchange coefficient and heat exchange efficiency of the heat exchanger, it is found that the thermal efficiency had been improved up to 0.77–0.83. Furthermore, the ICEPAK software and the standard k-ε RNG turbulence model were used to carry out simulations. The velocity and outlet temperature of fresh airflow and polluted airflow were simulated through setting different inlet temperatures of fresh air and polluted air inlet. Numerical results further indicated that the flow state was laminar flow. The micro heat pipe array side had small eddies and the heat transfer was significantly improved due to the flow of air along the surface of the micro heat pipe.

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