Experimental validation of a model for liquid levels and heat transfer rates in a closed two-phase thermosyphon

A method for the determination of steady-state liquid levels and heat transfer rates in a closed two-phase thermosyphon is presented and validated with experimental data from a copper thermosyphon with water as the working fluid, fluid inventory ranging from 25% to 150% of the evaporator volume, operating fluid temperatures ranging from 20°C to 120°C, and inclination 45° and vertical. In addition, the use of an internal downcomer is shown to increase the operating limit by 300%.