(230c) Enhanced Heat Transport in a Pulsating Heat Pipe Using a Self-Rewetting Working Fluid

New experimental results will be reported on the enhancement of heat transport by a pulsating heat pipe (PHP) using a self-rewetting fluid as a working fluid. Self-rewetting fluids have a property that the surface tension increases with temperature unlike other common liquids. The increasing surface tension at a higher temperature means that the liquid will be drawn towards a heated surface if a dry spot appears. Thus, in boiling, a dryout phenomenon may be prevented at a higher heat flux. In the present experiment, butanol was added to water at a concentration of less than 1 wt% to make the self-rewetting fluid. A pulsating heat pipe made from an extruded multiport tubing was partially filled with the butanol-water mixture and tested for its heat transport capability at different input power levels. One end of the PHP was heated using a copper block equipped with two cartridge heaters. A fin was attached to the opposite end to be cooled by a fan. The experiments showed that the maximum heat transport capability was enhanced by a factor of four when the maximum heater temperature was limited to 120 degrees C. Thus, the use of a self-rewetting fluid in a PHP has been shown to be highly effective in improving the heat transport capability of pulsating heat pipes.