FORCED CONVECTIVE BOILING IN BINARY-MIXTURES

ENEA started in 1990 a new research programme on 'Thermal Hydraulics Of Mixtures' (THOM) focused on the heat transfer in forced convective boiling of refrigerant mixtures. The main aim of the research is to accomplish new experimental data on binary mixtures in forced convective boiling and particularly on three main topics: convective boiling heat transfer, hysteresis in nucleate boiling incipience and critical heat flux. A first preliminary step of the research, started in the middle of 1990, consisted in the thermal hydraulic characterization of the pure components of the binary mixture chosen, namely R 12 (CCl2F2) and R 114 (C2Cl2F4). At the end of 1991 (and still in progress) the main investigation on the heat transfer performance of different compositions of an R 12/R 114 mixture started. In the present paper, a review of previous works, together with a description of the first experimental results on heat transfer coefficients is given. Finally a comparison of experimental data with the available correlations, is accomplished.