Thermal characterization of a multi-turn pulsating heat pipe in microgravity conditions: Statistical approach to the local wall-to-fluid heat flux

A Pulsating Heat Pipe (PHP), specifically designed to be hosted on board the Transfer Host of International Space Station, is tested in microgravity conditions during 67th Parabolic Flight Campaign promoted by European Agency. The device consists an aluminium tube (inner/outer diameter = 3/5 mm) closed a 14 turns loop, half filled with FC-72. PHP external wall temperature distribution are measured within adiabatic section means high-speed infrared camera. resulting thermographic images used as input data for solution Inverse Conduction Problem (IHCP) channels estimate local time-space heat fluxes exchanged at wall-fluid interface. adopted post-processing method represents one first attempts wall-to-fluid flux PHPs under conditions. comprehensive investigation performed overall original statistical approach order study working regimes. results highlight that such capable providing similar information regarding fluid motion inside those obtained traditional intrusive experimental methods (e.g. direct temperature-pressure measurements) or transparent inserts sapphire tube), which perturb layout and require complex set-up.