Experimental testing of mini heat pipes under microgravity conditions aboard a suborbital rocket

Heat pipe technologies have numerous applications under microgravity conditions in aerospace, from miniature devices in laptops used aboard the International Space Station (ISS) to heat transport systems in satellites. Advances in understanding the behavior of two-phase flow systems under microgravity conditions could lead to higher-efficiency devices and improved heat-exchanger designs. Under normal gravity conditions, heat pipes can function properly without any kind of capillary structure (thermosyphons, vertical position) or they can be aided by a wick material in the horizontal position, allowing the return of the condensate from the condenser to the evaporator. However, gravitational acceleration can significantly alter the flow regime, masking some effects that are not observed under microgravity conditions. This paper presents an experimental analysis of three miniature heat pipe technologies developed in Brazil for thermal management and heat dissipation of electronic devices under gravity and microgravity conditions. Different geometries of heat pipes charged with methanol were tested under microgravity conditions aboard a sounding rocket. Results demonstrated that the mini heat pipes present low thermal resistances for both gravity and microgravity conditions.