Thermal Performance of Cooling Enhancement of Miniature Flat Plate Heat Pipe Under Different Angle

2015 ◽  
Vol 32 (1) ◽  
pp. 93-100
Author(s):  
J.-S. Chen ◽  
J.-H. Chou
Keyword(s):  
Thermal Conductivity ◽  
Flat Plate ◽  
Effective Thermal Conductivity ◽  
Heat Pipes ◽  
Maximum Heat ◽  
Plate Heat ◽  
Tilting Angle ◽  
Cooling Enhancement ◽  
Flat Plate Heat Pipe ◽  
Heat Transport Capability

AbstractThe possibility of cooling enhancement of flat plate heat pipes (FPHPs) by tilting was examined experimentally in this study. All of the FPHPs were made of Al and were partially filled with acetone. They had the same size of 120 mm (length) by 36 mm (width) by 2.5 mm (thickness) and the same liquid filling ratio of 25.1%. The effects of six tilting angles of -30°, -15°, -10°, 0°, 45°, and 90° were explored. The results showed that the thermal resistance decreased and the effective thermal conductivity increased when the tilting angle was increased. By increasing the tilting angle from 0° to 45° and further to 90°, the maximum effective thermal conductivity increased by a factor of 1.205 from 4561 W/mK to 5497 W/mK and of 1.212 to 5530 W/mK, respectively. The corresponding maximum heat transport capability increased by a factor of 2.89 from 39.8 W to 115 W and of 3.27 to 130 W. Hence, by proper tilting into positve angles, cooling enhancement of the FPHPs can be greatly achieved.

Experimental and Statistical Analysis of MgO Nanofluids for Thermal Enhancement in a Novel Flat Plate Heat Pipes

2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760018 ◽  
Author(s):  
P. Pandiaraj ◽  
A. Gnanavelbabu ◽  
P. Saravanan
Keyword(s):  
Thermal Conductivity ◽  
Flat Plate ◽  
Volume Fraction ◽  
Heat Pipes ◽  
Influential Factors ◽  
Working Fluid ◽  
Particle Fraction ◽  
Solution Ph ◽  
Plate Heat ◽  
Xrd Techniques

Metallic fluids like CuO, Al2O3, ZnO, SiO2 and TiO2 nanofluids were widely used for the development of working fluids in flat plate heat pipes except magnesium oxide (MgO). So, we initiate our idea to use MgO nanofluids in flat plate heat pipe as a working fluid material. MgO nanopowders were synthesized by wet chemical method. Solid state characterizations of synthesized nanopowders were carried out by Ultraviolet Spectroscopy (UV), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) techniques. Synthesized nanopowders were prepared as nanofluids by adding water and as well as water/ethylene glycol as a binary mixture. Thermal conductivity measurements of prepared nanofluids were studied using transient hot-wire apparatus. Response surface methodology based on the Box–Behnken design was implemented to investigate the influence of temperature (30–60[Formula: see text]C), particle fraction (1.5–4.5 vol.%), and solution pH (4–12) of nanofluids as the independent variables. A total of 17 experiments were accomplished for the construction of second-order polynomial equations for target output. All the influential factors, their mutual effects and their quadratic terms were statistically validated by analysis of variance (ANOVA). The optimum stability and thermal conductivity of MgO nanofluids with various temperature, volume fraction and solution pH were predicted and compared with experimental results. The results revealed that increase in particle fraction and pH of MgO nanofluids at certain points would increase thermal conductivity and become stable at nominal temperature.

Thermal Performance of a Thin Flat Plate Heat Pipe

2009 ◽  
Author(s):  
Wei Qu ◽  
Shijuan Li ◽  
Hongwu Yang
Keyword(s):  
Thermal Conductivity ◽  
Flat Plate ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Tilt Angle ◽  
Test Results ◽  
Test Setup ◽  
Plate Heat ◽  
Flat Plate Heat Pipe ◽  
Performance Results

A thin flat plate heat pipe (TFPHP) with a new structure of wick is fabricated and tested. The wick is formed by the narrow foils folded, the liquid passage and capillary force is provided by the folded clearance of the foils, the vapor passage is shaped by the periodic holes of the foils. One aluminum TFPHP of 260×60×4 mm3 size is made and the test setup is established. The test results show that the spreader has good performance as, at the horizontal state, the power transferred can reach 18.5W, the corresponding thermal conductivity is 838W/(m·°C). For different tilt angle, we have the performance results. The effects of parameters to the performance are discussed. The spreader is significant for the spreading of point power.

Analysis of Asymmetric Disk-Shaped and Flat-Plate Heat Pipes

1995 ◽  
Vol 117 (1) ◽  
pp. 209-218 ◽  
Author(s):  
K. Vafal ◽  
N. Zhu ◽  
W. Wang
Keyword(s):  
Flat Plate ◽  
Heat Pipe ◽  
Surface Area ◽  
Heat Pipes ◽  
Analytical Investigation ◽  
Unit Surface Area ◽  
Plate Heat ◽  
Pressure Distributions ◽  
Transfer Capability ◽  
Flat Plate Heat Pipe

An analytical investigation and conceptual design of a disk-shaped asymmetric heat pipe is presented in this work. Using the conservative formulations for the steady incompressible vapor and liquid flow for a disk-shaped heat pipe, an in-depth integral analysis is applied. Analytical results for the asymmetric vapor velocity profile, the vapor and liquid pressure distributions, and the vapor temperature distribution in the heat pipe are obtained and compared to those of rectangular flat-plate heat pipe. The analysis establishes the physics of the process and the intrawick interactions for the disk-shaped heat pipe. The effects of variations in the thicknesses of the vapor channel and the wick as well as the heat pipe on the performance of both disk-shaped and rectangular flat-plate heat pipes are analyzed in detail and compared with each other. The factors limiting heat pipe performance are discussed and the results show that the disk-shaped heat pipe, while utilizing a smaller surface area and being more adaptable to several application areas, significantly increases the heat transfer capability per unit surface area compared to rectangular flat-plate heat pipe.

Thermo-Fluid Model for High Thermal Conductivity Thermal Ground Planes

2012 ◽  
Author(s):  
Mohammed T. Ababneh ◽  
Frank M. Gerner ◽  
Pramod Chamarthy ◽  
Peter de Bock ◽  
Shakti Chauhan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Gravitational Field ◽  
Effective Thermal Conductivity ◽  
Heat Transport ◽  
Fluid Model ◽  
Ground Plane ◽  
Maximum Heat ◽  
Gravitational Fields ◽  
Capillary Limit ◽  
Heat Transport Capability

The thermal ground plane (TGP) is an advanced planar heat pipe designed for cooling microelectronics in high gravitational fields. A thermal resistance model is developed to predict the thermal performance of the TGP, including the effects of the presence of non-condensable gases (NCGs). Viscous laminar flow pressure losses are predicted to determine the maximum heat load when the capillary limit is reached. This paper shows that the axial effective thermal conductivity of the TGP decreases when the substrate and/or wick are thicker and/or with the presence of NCGs. Moreover, it was demonstrated that the thermo-fluid model may be utilized to optimize the performance of the TGP by estimating the limits of wick thickness and vapor space thickness for a recognized internal volume of the TGP. The wick porosity plays an important effect on maximum heat transport capability. A large adverse gravitational field strongly decreases the maximum heat transport capability of the TGP. Axial effective thermal conductivity is mostly unaffected by the gravitational field. The maximum length of the TGP before reaching the capillary limit is inversely proportional to input power.

Thermal Performance of a Flat Plate Heat Pipe With Gradient Wettability

2013 ◽  
Author(s):  
Ping-Hei Chen ◽  
Hung-Hsia Chen ◽  
Bo-Rui Huang ◽  
Long-Sheng Kuo
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Heat Pipes ◽  
Contact Angles ◽  
Plate Heat ◽  
Flat Plate Heat Pipe ◽  
Superhydrophilic Surface ◽  
Gradient Surface

Many studies have been performed on the flat-plate heat pipes with sintered wick. It was found that during the evaporation process, the heat transfer characteristics of hydrophilic surface performed better than hydrophobic surface. This work investigated the heat transfer characteristics of flat-plate heat pipes in which the bottom surface was modified with various gradient contact angles by a sol-gel method. This method was applied to create a gradient surface on copper-plate surface. The coated nanoparticles were immobilized on the surface after the surface was heated in a furnace at a working temperature of 120°C. The thermal resistance results of flat plate heat pipes with either homogeneous superhydrophilic surface or a gradient wettability are reported in this study. For the gradient wettability, the evaporation region was super-hydrophilic and the condense region was super-hydrophobic. The heat transfer ability was both increased in evaporation region and condense region. Furthermore, the reflux ability of the working fluid was performed better due to the unbalanced surface tension on the gradient surface and the impact of gravity force of inclination angle (α). By manipulating different surfaces with different contact angles (gradient surface, contact angle = 150 ° /110 ° /20 ° /10 ° and uniform surface, contact angle <10°) and different inclination angles (α = 0°, 10°), we managed to find the better combination to improve the thermal performance of flat-plate heat pipe. The results indicated that the thermal performance of flat plate heat pipe with a gradient wettability is better than homogeneous superhydrophilic surface. The evaporation resistance of gradient wettability surface (gradient & α = 10°) has achieved to 0.098 °C /W, and reduced 30% than homogenous superhydrophilic surface (CA <10° & α = 0°). The gradient wettability surface in this work performed as well as the traditional sintered wick flat-plate heat pipe.

APPLICATION OF FLAT PLATE HEAT PIPE FOR COOLING SPACECRAFT ELECTRONICS

2014 ◽  
Vol 5 (1-4) ◽  
pp. 531-537
Author(s):  
D. R. Veeresha ◽  
Ch. SimhachalaRao ◽  
M. K. Shailandran ◽  
S. G. Barve ◽  
D. Kumar ◽  
...  
Keyword(s):  
Flat Plate ◽  
Heat Pipe ◽  
Plate Heat ◽  
Flat Plate Heat Pipe
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