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Experimental analysis of a Flat Plate Pulsating Heat Pipe with Self-ReWetting Fluids during a parabolic flight campaign

2018; Elsevier BV; Volume: 147; Linguagem: Inglês

10.1016/j.actaastro.2018.03.045

1879-2030

Anselmo Cecere, Davide De Cristofaro, Raffaele Savino, Vincent Ayel, Thibaud Solé-Agostinelli, Marco Marengo, Cyril Romestant, Yves Bertin,

Fluid Dynamics and Thin Films

A Flat Plate Pulsating Heat Pipe (FPPHP) filled with an ordinary liquid (water) and a self-rewetting mixture (dilutes aqueous solutions of long-chain alcohols with unusual surface tension behavior) is investigated under variable gravity conditions on board a 'Zero-g' plane during the 65th Parabolic Flight Campaign of the European Space Agency. The FPPHP thermal performance in terms of evaporator and condenser temperatures, start-up levels and flow regimes is characterized for the two working fluids and a power input ranging from 0 to 200 W (up to 17 W/cm2 at the heater/evaporator wall interface). The experimental set-up also includes a transparent plate enabling the visualization of the oscillating flow patterns during the experiments. For a low power input (4 W/cm2), the pulsating heat pipe filled with pure water is not able to work under low-g conditions, because the evaporator immediately exhibits dry-out conditions and the fluid oscillations stops, preventing heat transfer between the hot and cold side and resulting in a global increase of the temperatures. On the other hand, the FPPHP filled with the self-rewetting fluid runs also during the microgravity phase. The liquid rewets several times the evaporator zone triggering the oscillatory regime. The self-rewetting fluid helps both the start-up and the thermal performance of the FPPHP in microgravity conditions.