JAPANESE JOURNAL OF MULTIPHASE FLOW
Online ISSN : 1881-5790
Print ISSN : 0914-2843
ISSN-L : 0914-2843
Papers:
Condensation Heat Transfer for Downward Flows of Steam-Air Mixture in a Circular Pipe
Michio MURASEYoichi UTANOHARAShigeo HOSOKAWAAkio TOMIYAMA
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2020 Volume 34 Issue 4 Pages 510-519

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Abstract

In our previous study, we measured the radial and axial temperature distributions of steam-air mixture in a vertical circular pipe (diameter, 49.5 mm; cooling height, 610 mm) and the cooling water in the annulus gap (8.5 mm) outside the pipe, and the temperature gradients in the pipe wall (thickness, 5.5 mm) between the steam-air mixture and cooling water. From the temperatures, we evaluated condensation heat fluxes qc, and derived an empirical correlation. In this study, we have calculated the heat transfer coefficient of the condensate film hf with the Nusselt equation and evaluated the condensation heat transfer coefficient hc from qc and the measured temperature distributions. We also compared hc with hc correlations based on the heat and mass transfer analogy and the diffusion layer model. Results from both correlations agreed relatively well with the hc data, but the correlations underestimated hc for high hc near the inlet with a thin thermal boundary layer and overestimated hc for low hc.

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© 2020 by The Japanese Society for Multiphase Flow
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