Heat transfer within a flat micro heat pipe with extra liquid

2016 ◽  
Author(s):  
Silviu Sprinceana ◽  
Ioan Mihai
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Micro Heat Pipe

scholarly journals An investigation on effect of EDL on heat transfer of micro heat pipe with square and triangular cross section

2020 ◽  
Vol 21 (3) ◽  
pp. 309
Author(s):  
Maryam Fallah Abbasi ◽  
Hossein Shokouhmand ◽  
Morteza Khayat
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Double Layer ◽  
Electric Double Layer ◽  
Heat Pipes ◽  
The Body ◽  
Working Fluid ◽  
Two Phase ◽  
Micro Heat Pipe ◽  
Micro Heat Pipes

Electronic industries have always been trying to improve the efficiency of electronic devices with small dimensions through thermal management of this equipment, thus increasing the use of small thermal sinks. In this study micro heat pipes with triangular and square cross sections have been manufactured and tested. One of the main objectives is to obtain an understanding of micro heat pipes and their role in energy transmission with electrical double layer (EDL). Micro heat pipes are highly efficient heat transfer devices, which use the continuous evaporation/condensation of a suitable working fluid for two-phase heat transport in a closed system. Since the latent heat of vaporization is very large, heat pipes transport heat at small temperature difference, with high rates. Because of variety of advantage features these devices have found a number of applications both in space and terrestrial technologies. The theory of operation micro heat pipes with EDL is described and the micro heat pipe has been studied. The temperature distribution have achieved through five thermocouples installed on the body. Water and different solution mixture of water and ethanol have used to investigate effect of the electric double layer heat transfer. It was noticed that the electric double layer of ionized fluid has caused reduction of heat transfer.

scholarly journals Heat transfer performance of a micro heat pipe array for battery thermal management systems

2020 ◽  
Vol 65 (31) ◽  
pp. 3485-3496
Author(s):  
Yueqi Wang ◽  
Yuping Qian ◽  
Weilin Zhuge ◽  
Dan Dan ◽  
Chengning Yao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Management ◽  
Heat Transfer Performance ◽  
Management Systems ◽  
Transfer Performance ◽  
Micro Heat Pipe ◽  
Battery Thermal Management

A Mathematical Modeling Method for Capillary Limit of Micro Heat Pipe with Sintered Wick

2011 ◽  
Vol 175 ◽  
pp. 335-341
Author(s):  
Xi Bing Li ◽  
Chang Long Yang ◽  
Gong Di Xu ◽  
Wen Yuan ◽  
Shi Gang Wang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Pipe ◽  
Heat Dissipation ◽  
High Heat ◽  
Experimental Investigations ◽  
High Heat Flux ◽  
Micro Heat Pipe ◽  
Copper Powders ◽  
Capillary Limit

With heat flux increasing and cooling space decreasing in microelectronic and chemical products, micro heat pipe has become an ideal heat dissipation device in high heat-flux products. Through the analysis of its working principle, the factors that affect its heat transfer limits and the patterns in which copper powders are arrayed in circular cavity, this paper first established a mathematical model for the crucial factors in affecting heat transfer limits in a circular micro heat pipe with a sintered wick, i.e. a theoretical model for capillary limit, and then verified its validity through experimental investigations. The study lays a powerful theoretical foundation for designing and manufacturing circular micro heat pipes with sintered wicks.

Temperature Response of Heat Transport in a Micro Heat Pipe

1999 ◽  
Vol 121 (2) ◽  
pp. 438-445 ◽  
Author(s):  
G. P. Peterson ◽  
H. B. Ma
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transport ◽  
Capillary Flow ◽  
Temperature Drop ◽  
Temperature Response ◽  
Axial Direction ◽  
Vapor Flow ◽  
Micro Heat Pipe

A detailed mathematical model for predicting the heat transport capability and temperature gradients that contribute to the overall axial temperature drop as a function of heat transfer in a micro heat pipe has been developed. The model utilizes a third-order ordinary differential equation, which governs the fluid flow and heat transfer in the evaporating thin film region; an analytical solution for the two-dimension heat conduction equation, which governs the macro evaporating film region in the triangular corners; the effects of the vapor flow on the liquid flow in the micro heat pipe; the flow and condensation of the thin film caused by the surface tension in the condenser; and the capillary flow along the axial direction of the micro heat pipe. With this model, the temperature distribution along the axial direction of the heat pipe and the effect on the heat transfer can be predicted. In order to verify the model presented here, an experimental investigation was also conducted and a comparison with experimental data made. This comparison indicated excellent correlation between the analytical model and experimental results, and as a result, the analysis provides a better understanding of the heat transfer capability and temperature variations occurring in micro heat pipes.

Circulation Effectiveness of Working Fluid in Inclined Micro Heat Pipes

2015 ◽  
Vol 789-790 ◽  
pp. 422-425
Author(s):  
Fun Liang Chang ◽  
Yew Mun Hung
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Pipes ◽  
Operating Conditions ◽  
Circulation Rate ◽  
Working Fluid ◽  
High Heat Flux ◽  
Micro Heat Pipe ◽  
Micro Heat Pipes

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.

Heat Transfer Limitation of a Micro Heat Pipe

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
K. N. Shukla
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transport ◽  
Analytical Expression ◽  
Micro Heat Pipe ◽  
Capillary Limit ◽  
Heat Transport Capability

An analytical expression for the heat transport capability of micro heat pipe is derived. The vapor continuum limitation has been considered in deriving the heat transport capability of a micro heat pipe. As the micro heat pipe uses sharp-cornered square, triangular, or other polygonal channels that can serve as capillary arteries, its transport capability depends on the capillary limit. It has been shown that the operating limit of the micro heat pipe depends on the vapor continuum limitation, capillary limit, and the gravity.

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

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 675 ◽  
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.

scholarly journals Heat transfer analysis of looped micro heat pipes with graphene oxide Nanofluid for Li-ion battery

2020 ◽  
pp. 218-218
Author(s):  
Prabu Manikanda ◽  
G. Sureshkannan ◽  
S. Suresh ◽  
Kumar Senthil
Keyword(s):  
Heat Transfer ◽  
Graphene Oxide ◽  
Heat Pipe ◽  
Heat Transfer Analysis ◽  
New Combination ◽  
Working Fluid ◽  
Li Ion Batteries ◽  
Li Ion Battery ◽  
Micro Heat Pipe ◽  
Li Ion

Li-ion batteries play a vital role in electromechanical devices. The heat load on such batteries varies with time and application which falls as high-temperature rise and it causes severe damages on a device and reduces the life cycle. It will be a big challenge in future decades of electronic devices and the electric car revolution. To overcome such difficulties, this work is considered for thermal management of small Li-ion batteries to check the possibilities through the micro heat pipe. Due to the high impact of Nanotechnology in heat transfer science, Acetone, De-ionized water, and Tetrahydrofuran fluids are blended with Graphene Oxide Nanoparticles to prepare the Nanofluids by ultrasonic method. Here, Tetrahydrofuran is a new combination of Nano-working fluid and not addressed by pre-researchers. Tetrahydrofuran-graphene Nanofluid provides 61% of improved thermal conductivity than the other two fluids which accelerates the heat transfer rate with reduced thermal resistance in the range of 0.09- 0.640C/W. To validate the experimental results, a real-time study has been done on Li-ion batteries for a day and ensured the reduction of overheat issues. Hence, the present work will support the Li-ion battery to work in an optimal temperature range in a new way of micro heat pipe with Nanofluid.

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