Near-critical fluids under microgravity: Highlights and perspectives for Europe

Started more than 15 years ago, the investigation of fluids and liquid mixtures near their gas-liquid or liquid-liquid critical points has led to a number of important findings. We note the determination of critical, universal power law behavior, for the specific heat and the adsorption properties near a solid wall. Also came out a unified view of phase separation, which has-been later applied to the development of biological patterns. A new, very fast, mechanism of heat transport has been discovered that has been coined "piston effect". This effect has been already applied in the space industry. All these findings have been obtained thanks to a good coordination between ESA and CNES (and also with the NASA and USSR - Russian space agencies). The future of the program is linked to the CNES DECLIC facility and the ESA Fluid Science Laboratory (FSL). DECLIC has been designed to extend the interval of temperature regulation beyond the critical temperature of water (550 K) so as to investigate chemical reactions under conditions of supercritical water. Thanks to the construction of a special vibrational Experiment Container for FSL, the thermal and mechanical behavior of fluids under forced vibration can be investigated.