Augmentation of horizontal in-tube condensation of steam

The complete condensation of low pressure steam inside smooth and augmented horizontal tubes has been experimentally investigated. Smooth tubes were tested to establish reference conditions and to check existing in-tube condensation heat transfer predictive methods. Inclined tubes, twisted tape inserts, and internally finned tubes were tested as passive techniques to augment condensation. Tube inclination produced only modest improvements in heat transfer. Four internally finned tubes produced increases in heat transfer coefficients as much as 150 percent above smooth tube values.