Condensation heat transfer characteristics and flow regime in a horizontal rectangle channel of a multichannel cylinder dryer.

The present study investigates the phenomenon of steam condensation in a rectangle horizontal channel with a mass flux range of 20–70 kg/m2/s and a vapor quality of 0.2–0.8. Mass flux and vapor quality were presented to primarily affect the heat transfer coefficient in shear-dominated flow regime, such as the mass flux is greater than 40 kg/m2/s. At the low mass flux, only slug flow, plug flow, and wave flow were observed. At the high mass flux, the wave flow and annular flow were observed even at the low-vapor quality, and the slug and plug flow were not found during the entire condensation process. Observed flow patterns agreed with Tandon’s flow pattern map. Four kinds of correlations are employed to predict the condensing heat transfer coefficient, and the result reveals that Cavallini’s correlation agrees with the experimental results relatively well. The measured pressure drop has a good agreement with the Lockhart–Martinelli correlation. [ABSTRACT FROM PUBLISHER]