Numerical Study of the VOF Model for Film-Wise Condensation in Rounded, Elliptical, and Flattened Tubes

The film-wise condensation within horizontal tubes has been widely studied, focusing on various vapors, including refrigerants and steam, in different geometries. Heat transfer coefficient and flow patterns significantly impact condensation efficiency. This study examines film-wise condensation of saturated steam in microchannels with rounded tubes (4 mm diameter, 10 cm length) and their elliptical and flattened variations. Using the Volume of Fluid (VOF) method, we analyzed temperature, pressure, velocity, film thickness, and flow rate effects on heat transfer. COMSOL simulations showed that heat transfer increased by 3% in elliptical tubes and 7% in flattened tubes for a 1 K surface-to-vapor temperature difference. These findings provide insights into film growth and detachment, contributing to heat transfer optimization in industrial applications.