Experimental analysis and transient numerical simulation of a large diameter pulsating heat pipe in microgravity conditions

A multi-parametric transient numerical simulation of the start-up a large diameter Pulsating Heat Pipe (PHP) specially designed for future experiments on International Space Station (ISS) are compared to results obtained during parabolic flight campaign supported by European Agency. Since channel is larger than capillary limit in normal gravity, such device behaves as loop thermosyphon ground and PHP weightless conditions; therefore, microgravity environment mandatory pulsating mode. Because short duration flight, data concerns only behavior device. One most comprehensive models literature, namely in-house 1-D code CASCO (French acronym Code Avancé de Simulation du Caloduc Oscillant: Advanced English), has been configured terms geometry, topology, material properties thermal boundary conditions model experimental The comparison between performed simultaneously temporal evolution multiple parameters: tube wall temperature, pressure and, wherever possible, velocity liquid plugs, their length temperature distribution within them. agree with experiment different input powers. Temperatures predicted maximum deviation 7%. Pressure variation trend qualitatively captured well plug velocity, distribution. also shows ability capturing instant when fluid begins oscillate after heat load supplied, which fundamental information correct design engineering that will be tested ISS. We reveal existence strong gradients near ends plugs both experimentally simulation. Finally, theoretical prediction stable functioning given. Results show system provided an power 185W should able reach steady state 1min maintain operation from then on.