Thermal performance of anodized two phase closed thermosyphon (TPCT)

The thermal performance of an anodized two phase closed thermosyphon (TPCT) is studied and compared with that of a non-anodized one. A simple and cost-effective anodizing technique is used to prepare the porous structure on the inner wall of TPCT. Operational limits of TPCT are estimated and experimental conditions are chosen well below these limits. The anodized and non-anodized TPCTs charged with acetone are tested for the heat input range of 50-250 W. The effect of the porous structure on the thermal performance of the TPCT is theoretically explained in terms of nucleation site density and bubble diameter. Experimental results show that the nucleation sites present in the anodized surface are at least 2-3 times higher than that of the ordinary surface. Though the effect of anodized surface is significant on the thermal resistance and heat transfer coefficient of the evaporator, the same is negligible on the thermal resistance and heat transfer coefficient of the condenser. A study is also conducted to test the thermal stability of the anodized surface prepared on the inner wall of the TPCT. (C) 2013 Elsevier Inc. All rights reserved.