Characterization and performance of a 3D-printed two-phase closed thermosyphon

We report our experimental study of the performance of a 3D-printed closed two-phase thermosyphon. Using laser powder-bed fusion (L-PBF) technique, the thermosyphon has been additively manufactured with stainless steel (316L), which has excellent resistance and compatibility with chemicals and coolants. The specific feature of the thermosyphon and the novelty of the study is that the device is printed as a single unit, including an extruded helical heat exchanger into the condenser body and integrated pillar arrays in the evaporation section. The evaporation, adiabatic, and condensation section lengths are 20 mm, 30 mm, and 50 mm, respectively. The micropillars size is 2.5 mm. We considered the effects of the filling ratio of acetone as a working fluid and heat flux on the thermal performance of the thermosyphon. The filling ratios used are 0%, 1.7%, 4.9%, 6.3%, 10.4%, 17.1%, 27.9%, 40.5%, 50.4%, 64.2%, 76.6%, and 84.1%. We found that the minimum total thermal resistance is 0.48?.W-1, which is achieved at the minimal value of the filling ratio of 1.7% and thermal power of 13.7 W. The filling ratio of 4.9% shows the best stable thermal performance of the thermosyphon.