Fractal Loop Heat Pipe Heat Flux and Operational Performance Testing

This study investigates heat flux performance for a LHP that includes a fractal based evaporator design. The prototype Fractal Loop Heat Pipe (FLHP) was designed and manufactured by Mikros Manufacturing Inc. and validation tested at NASA Goddard Space Flight Center’s Thermal Engineering Branch laboratory. Heat input to the FLHP was supplied via cartridge heaters mounted in a copper block. The copper heater block was placed in intimate contact with the evaporator. The evaporator had a circular cross-sectional area of 0.877 cm². Twice distilled, deionized water was used as the working fluid. Thermal performance data was obtained for three different Condenser/Subcooler temperature combinations under degassed conditions (P_sat = 25.3 kPa at 22°C). The FLHP demonstrated successful start-ups in each of the test cases performed. Test results show that the highest heat flux demonstrated was 75 W/cm².