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.

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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