Characterization of flat miniature loop heat pipe using water and methanol at different inclinations

Experiments have been conducted on a flat rectangular loop heat pipe with water and methanol at heat loads from 40 to 320 W at three orientations of the heat pipe (0 degrees, 45 degrees, 90 degrees) and two filling ratios (33% and 50%). Performance parameters such as thermal resistance, effective thermal conductivity and capillary limit are calculated from the experimental data. The results exhibited that the thermal performance of water is better than methanol with least thermal resistance 0.13 K/W, maximum capillary limit 2626.72 W and an effective thermal conductivity 84490.48 W/mK at a heat load 320 W in horizontal position for 33% filling ratio.