Experimental Investigation of Thermal Conduction Performance on Silicon-Based Micro Flat Heat Pipe

2015 ◽  
Vol 645-646 ◽  
pp. 1032-1037
Author(s):  
Cong Ming Li ◽  
Yi Luo ◽  
Chuan Peng Zhou ◽  
Liang Liang Zou ◽  
Xiao Dong Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Pipe ◽  
Effective Thermal Conductivity ◽  
Thermal Performance ◽  
Axial Direction ◽  
Filling Ratio ◽  
Parallel Structure ◽  
Working Fluid ◽  
Vacuum Degree ◽  
Structure Dimension

There are several factors that affect heat transfer of heat pipe, for example, structure dimension, filling ratio and vacuum degree of charging. This paper studied the thermal conductivity of micro flat heat pipes (MFHPs) with different structure dimension and with different filling ratio, when the charging vacuum degree of MFHP was decided. When electric power was 2W or 4W, MFHPs with parallel grooves and nonparallel grooves, charged by working fluid with different filling ratio, were carried out. And the filling ratio is 30%, 40% and 50%, respectively. The better thermal performance of MFHP can be evaluated by lower thermal resistance and higher effective thermal conductivity. The experiment results show that MFHP has the highest effective thermal conductivity when the filling ratio is 40%; and the thermal performance of MFHP with nonparallel structure in axial direction is better than that of MFHP with parallel structure.

Experimental Investigation on Thermal Performance of Flat Plate Heat Pipe with Intersected Micro-Grooves

2013 ◽  
Vol 772 ◽  
pp. 480-486 ◽  
Author(s):  
Chen Wang ◽  
Zhong Liang Liu ◽  
Guang Meng Zhang
Keyword(s):  
Thermal Resistance ◽  
Flat Plate ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Radial Direction ◽  
Filling Ratio ◽  
Working Fluid ◽  
Plate Heat ◽  
Inclination Angles ◽  
Flat Plate Heat Pipe

A copper-water flat plate heat pipe with intersected micro-grooves was developed for cooling electronic devices in this paper. The effects of heat flux, working fluid filling ratio and inclination angles on thermal performance of the flat plate heat pipe was tested and investigated. The laboratory tests show the optimal filling ratio of the heat pipe is about 65%. Excellent thermal performance is also observed in unfavorable titled positions including vertical and anti-gravity orientation at 65%. The smallest overall thermal resistance is obtained in horizontal position and the maximal thermal resistance is observed in vertical position. The influence of inclination angles on thermal performance of the heat pipe in both axial direction and radial direction is also investigated. As the heat pipe is tilted, the ability of temperature leveling in radial direction is enhanced, nevertheless, the capacity of heat transfer in radial direction decreased at the same time.

A Review on Nanofluid Heat Pipe

2014 ◽  
Author(s):  
Maryam Shafahi ◽  
Kevin Anderson ◽  
Ali Borna ◽  
Michael Lee ◽  
Alex Kim ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
Working Fluid ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Medical Instruments ◽  
Thermo Physical Properties

This paper reviews the improvement in the heat pipe’s performance using nanofluid as the working fluid. The use of nanofluid enhances heat transfer in the heat pipe due to its improved thermo-physical properties, such as a higher thermal conductivity. Nanofluids proved to be the innovative approach to a variety of applications, such as electronics, medical instruments, and heat exchangers. The influence of different nanoparticles on heat pipe’s performance has been studied. Utilizing nanofluid as the working fluid leads to a significant reduction in heat pipe thermal resistance, an increase in maximum heat transfer, and an improvement of heat pipe thermal performance.

scholarly journals Experimental Investigation on the Thermal Performance of Pulsating Heat Pipe Heat Exchangers

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 269 ◽  
Author(s):  
Kai-Shing Yang ◽  
Ming-Yean Jiang ◽  
Chih-Yung Tseng ◽  
Shih-Kuo Wu ◽  
Jin-Cherng Shyu
Keyword(s):  
Heat Exchanger ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
Filling Ratio ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Evaporator Temperature ◽  
Inner Diameter ◽  
Air Streams

In this study, the vertically-oriented pulsating heat pipe (PHP) heat exchangers charged with either water or HFE-7000 in a filling ratio of 35% or 50% were fabricated to exchange the thermal energy between two air streams in a parallel-flow arrangement. Both the effectiveness of the heat exchangers and the thermal resistance of PHP with a size of 132 × 44 × 200 mm, at a specific evaporator temperature ranging from 55 to 100 °C and a specific airflow velocity ranging from 0.5 to 2.0 m/s were estimated. The results show that the heat pipe charged with HFE-7000 in either filling ratio is likely to function as an interconnected array of thermosiphon under all tested conditions because of the unfavorable tube inner diameter, whereas the water-charged PHP possibly creates the pulsating movement of the liquid and vapor slugs once the evaporator temperature is high enough, especially in a filling ratio of 50%. The degradation in the thermal performance of the HFE-7000-charged PHP heat exchanger resulted from the non-condensable gas in the tube became diminished as the evaporator temperature was increased. By examining the effectiveness of the present heat exchangers, it is suggested that water is a suitable working fluid while employing the PHP heat exchanger at an evaporator temperature higher than 70 °C. On the other hand, HFE-7000 is applicable to the PHP used at an evaporator temperature lower than 70 °C.

A Capillary-Wick Heat Pipe Fabricated on a Plastic Board (Fundamental Experiments on Heat Transport Characteristics)

2015 ◽  
Author(s):  
Yasushi Koito ◽  
Hiroyuki Maehara ◽  
Daisuke Shimada ◽  
Toshio Tomimura
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Phase Change ◽  
Heat Pipe ◽  
Effective Thermal Conductivity ◽  
Working Fluid ◽  
Experimental Investigations ◽  
Liquid Volume ◽  
Experimental Conditions ◽  
Phase Change Heat Transfer

A capillary-wick heat pipe having the dimensions of 5.0 mm × 5.0 mm × 100 mm (length) is fabricated on a surface of a plastic board, and the experimental investigations are conducted on the operational characteristics of the heat pipe. Plastics are easy to manufacturing, lightweight, low cost, flexible, and besides, the present study aims at the phase-change heat transfer inside the plastic board. A sintered copper powder and water are used as the wick structure and the working fluid of the heat pipe, respectively. In experiments, an evaporator section of the heat pipe is heated by a heater while a condenser section is water-cooled by a heat sink. A heat input and a liquid volume inside the heat pipe are changed, and the temperature distribution of the heat pipe is measured by thermocouples. Moreover, a one-dimensional thermal circuit model is made to evaluate the effective thermal conductivity of the heat pipe. From the experimental results, the continuous phase-change heat transfer inside the plastic board and its effectiveness are confirmed. It is also revealed that the effective thermal conductivity of the heat pipe is 854 W/(m·K) in maximum under the present experimental conditions.

Analysis of CuO-Water Nanofluid Application on Heat Pipe

2014 ◽  
Vol 590 ◽  
pp. 234-238
Author(s):  
Nandy Putra ◽  
Wayan Nata Septiadi ◽  
Ranggi Sahmura
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Research Area ◽  
Working Fluid ◽  
Research Subject ◽  
High Concentration ◽  
Low Concentration ◽  
The World

Since their first introduction to the world, both heat pipe and nanofluid have caught the interest of many researchers. Heat pipe with its unique and exceptional capability in transferring heat passively and effectively, was studied intensively and developed extensively for many applications. While nanofluid with its higher thermal conductivity and some other upgraded properties compared to conventional fluid rose as appealing research subject especially on fluid and thermal research area. This study analyzes the utilization of CuO-water nanofluid on biomaterial wick heat pipe. Laboratory-developed CuO-water nanofluid was used as working fluid for vertically straight-shaped biomaterial wick heat pipe. From the experiment, it was shown that the application of CuO-water nanofluid reduced the heat pipe thermal resistance up to 83%. It was figured out that this enhancement is due to the combination of higher thermal conductivity and better wettability of the fluid. It was also found that the heat pipe with nanofluid did not show significant degradation though being inactivated for several weeks. However, it was figured out that unlike the application of low concentration nanofluid, application of high concentration nanofluid was insignificant in improving thermal performance of the heat pipe.

Steady-State Investigation of Vapor Deposited Micro Heat Pipe Arrays

1995 ◽  
Vol 117 (1) ◽  
pp. 75-81 ◽  
Author(s):  
A. K. Mallik ◽  
G. P. Peterson
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Surface Temperature ◽  
Heat Pipe ◽  
Effective Thermal Conductivity ◽  
Heat Pipes ◽  
Temperature Gradients ◽  
Bottom Surface ◽  
Micro Heat Pipe ◽  
Micro Heat Pipes

An experimental investigation of vapor deposited micro heat pipe arrays was conducted using arrays of 34 and 66 micro heat pipes occupying 0.75 and 1.45 percent of the cross-sectional area, respectively. The performance of wafers containing the arrays was compared with that of a plain silicon wafer. All of the wafers had 8 × 8 mm thermofoil heaters located on the bottom surface to simulate the active devices in an actual application. The temperature distributions across the wafers were obtained using a Hughes Probeye TVS Infrared Thermal Imaging System and a standard VHS video recorder. For wafers containing arrays of 34 vapor deposited micro heat pipes, the steady-state experimental data indicated a reduction in the maximum surface temperature and temperature gradients of 24.4 and 27.4 percent, respectively, coupled with an improvement in the effective thermal conductivity of 41.7 percent. For wafers containing arrays of 66 vapor deposited micro heat pipes, the corresponding reductions in the surface temperature and temperature gradients were 29.0 and 41.7 percent, respectively, and the effective thermal conductivity increased 47.1 percent, for input heat fluxes of 4.70 W/cm2. The experimental results were compared with the results of a previously developed numerical model, which was shown to predict the temperature distribution with a high degree of accuracy, for wafers both with and without the heat pipe arrays.

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