Experimental Study of Film Condensation of FC-72 Vapour on Disk-Shaped Fin

The results of activity made in the framework of preparation of the experiment SAFIR (Single fin condensAtion: FIlm local measuRements) of European Space Agency are presented. First prototype of the test cell has been developed and tested. Confocal technique has been adopted for condensate film thickness measurements. Experiments on condensation of the liquid FC-72 have been carried out. Average heat transfer coefficient has been measured in the range of 880-1440 W/m 2 K and compared to the Nusselt theory. © 2011 Springer Science+Business Media B.V.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Reasons of interaction between the categories of evaluation and negation

Глущук-Олея, А. И. Предпосылки взаимосвязи категорий оценки и отрицания / А. И. Глущук-Олея // European Applied Sciences.Section 13. Philology and linguistics. – Stuttgart, Germany : ORT Publishing, 2013. - № 3.– Р. 152 -154

Experimental investigation of liquid film thickness and heat transfer during condensation in microgravity

Considering the increasing complexity of future space missions and the growth of heat fluxes to be removed in next generation satellites, thermal control systems will be asked to provide high heat dissipation rates with reduced power input, size and weight. Two-phase systems represent a reliable technical solution to meet all these specifications but their accurate design requires validated tools and a deeper understanding of the effect of gravity on heat transfer. While several experiments and numerical simulations have been conducted to investigate the gravity effect on pool and flow boiling, studies on in-tube condensation under reduced gravity conditions are still limited in the literature. In the present work, the effect of gravity is experimentally investigated during condensation of HFE-7000 inside a 3.38 mm internal diameter channel with mass velocity ranging from 30 kg m−2 s−1 to 50 kg m−2 s−1. Condensation tests were carried out during the 70th ESA (European Space Agency) Parabolic Flight Campaign by simultaneously measuring the liquid film thickness and the heat transfer coefficient inside the channel in both normal gravity and microgravity conditions. The liquid film thickness is determined by coupling a shadowgraph technique with the measurements performed by a chromatic confocal sensor and an interferometer. The reduced gravity condition is responsible for a heat transfer penalization with respect to normal gravity, which is found to be more severe when the mass velocity decreases. The change in the gravity level affects the characteristics of the interfacial waves in terms of frequency, height and velocity. The prediction accuracy of several models for annular flow condensation is assessed against the experimental results taken in microgravity conditions