Title :
Experimental study of evaporation resistance on porous surfaces in flat heat pipes
Author :
Chien, Liang-Han ; Chang, C.-C.
Author_Institution :
Dept. of Mech. Eng., Chang-Gung Univ., Touyuan, Taiwan
Abstract :
This experimental study investigated the effect of particle size and coating thickness of the porous surface on evaporator thermal resistance of a thermosyphon having a 16 mm diameter circular heating area. Copper particles having two kinds of size distributions were sintered on a copper plate. The two particle distributions were 115 μm average diameter in the range 50 to 500 μm, and 247 μm average diameter in the range 180 to 350 μm. The particle coating thickness was either 0.5 or 1.0 mm for each distribution. Water was used as the working fluid, and it was tested at 60 or 70°C saturation temperature, which corresponds to sub-atmospheric saturation pressure. The heat flux varied between 30 and 550 kW/m2. The boiling surfaces were tested in vertical and horizontal orientations, and the experimental results showed negligible effect on the surface orientation. The best boiling surface in the present study is obtained with a coating 1.0 mm thick and 247 μm average particle diameter. At 70°C this surface yielded less than 0.025 K/W evaporation thermal resistance at 93 W.
Keywords :
boiling; cooling; copper; evaporation; flow through porous media; heat pipes; packaging; particle size; thermal resistance; 0.5 mm; 1.0 mm; 115 micron; 16 mm; 180 to 350 micron; 247 micron; 50 to 500 micron; 60 C; 70 C; 93 W; Cu; Cu particle size distributions; boiling surfaces; circular heating area; electronics cooling; evaporation thermal resistance; flat heat pipes; heat flux; horizontal orientation; particle coating thickness; particle size; porous surfaces; saturation temperature; sintering; sub-atmospheric saturation pressure; thermosyphon; vertical orientation; water working fluid; Coatings; Electronics cooling; Heat sinks; Heat transfer; Resistance heating; Surface resistance; Temperature; Testing; Thermal conductivity; Thermal resistance;
Conference_Titel :
Thermal and Thermomechanical Phenomena in Electronic Systems, 2002. ITHERM 2002. The Eighth Intersociety Conference on
Print_ISBN :
0-7803-7152-6
DOI :
10.1109/ITHERM.2002.1012463
