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ARTICLE:
Dr. Olivier Lebaigue
DER/SSTH/LMDL, Commissariat à l’Energie Atomique/Grenoble, 38054 Grenoble Cedex 9, France C. Colin
Institut de Mecanique des Fluides de Toulouse, Groupe Interface, Toulouse, France A. Larue de Tournemine
CNES-Toulouse, DCT/TV/TH, Toulouse, France
ABSTRACT An experimental setup, named Cyrene, was used to measure heat transfer coefficients in forced convection boiling and condensation in ammonia under microgravity conditions in a 4.8 mm ID aluminium pipe. Results were obtained with a wall heat flux at the evaporator up to 5 kW·m−2. Ammonia mass flow rate and quality values ranged up to 0.24 g·s−1 and 0.8, respectively. The saturation pressure of the loop was imposed between 0.9 and 1.8 MPa, which corresponds to a saturation temperature approximately between 20 and 45 °C.
The experimental results presented in this paper were obtained during two parabolic flight campaigns and one sounding rocket flight. Two-phase heat transfer coefficients in boiling and condensation are compared to literature correlations. The sounding rocket flight results confirm the trends observed during parabolic flights for boiling heat transfer. For condensation heat transfer, usual general correlations did not predict the observed trends. However, better predictions are obtained by using a method based on a coupling of the void fraction with the interfacial shear rate.
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