  Passive thermal spreaders utilizing liquid/vapor phase-change mechanism such
as heat pipes, have been widely used in the macro-scale thermal management of
electronic devices for many years. Micro-fabrication techniques enabled the
fabrication micro-scale grooved heat pipes on semiconductors. Recent advances
in fabrication techniques, on the other hand, enabled producing nano- and
{\AA}ngstr\"om-scale capillaries and cavities, which renders the manufacturing
of nanoscale heat pipes possible. In the present study, we have simulated
nanoscale heat pipes composed of nano-grooves using molecular dynamics and
evaluated their performance based on different operating parameters such as the
filling ratio and heat load. Moreover, evaluation of size effect on the thermal
performance is made by comparing proportionally scaled heat pipes. Simulation
results reveal that efficient operation of nano-grooved heat pipes depend not
only on the proper selections of filling ratio and heat load, but also on the
geometrical parameters such as cross sectional dimensions and aspect ratio of
the groove. The modeling strategy used in this study opens an opportunity for
computational experimentation of nanoscale heat pipes.
