Condensation heat transfer of steam-air mixture on vertical flat plate under mixed and natural convection conditions

Experiments on condensation heat transfer of steam-air mixture under natural and mixed convection conditions were conducted using a vertical rectangular channel (100 × 100 mm 2 cross section) with a cooling wall of 1100 mm length. The steam mass fraction and mixed gas flow rate were systematically varied, and the maximum value of the former was 0.80, which is larger than those reported in open literature (e.g. the COPAIN experiment). The streamwise distributions of gas temperature, wall temperature, and coolant temperature were measured to obtain the heat fluxes in the streamwise direction. The applicability of available condensation heat transfer correlations were assessed by comparing their predictions with the measured data. As a result, for natural convection, the Murase and Takaki correlation, which is based on the Spalding-type formulation while the suction correction factor and the Sherwood number for natural convection are employed, showed the best performance among the correlations tested. For mixed convection, the weighted average with the heat fluxes for forced and natural convection recommended by Takaki et al. worked well. • Condensation experiment of steam-noncondensable gas mixture was conducted. • Condensation heat transfer under mixed and natural convections was measured. • Heat transfer correlations were assessed using the obtained datasets. • Functional form for forced convection is also valid for natural convection.