Surface tension-driven flow in wickless heat pipes with self-rewetting fluids

Surface tension-driven effects in wickless heat pipes with aqueous solutions of long-chain alcohols are investigated. Flow visualizations and numerical simulation of bubbles behaviour and boiling pattern in transparent capillaries show the potential advantages of ‘‘self-rewetting” fluids, i.e. liquid solutions with a non-linear dependence of the surface tension with temperature. Surface tension measurements at different temperatures have been carried out also for a number of ternary aqueous solutions with relatively low freezing points. Some of them interestingly exhibit the same anomalous positive surface tension gradient with temperature as binary self-rewetting solutions. These results may open new horizons toward the development of more efficient heat transfer devices for different applications.