Tube-side heat transfer and friction characteristics of titanium corrugated tubes used for steam condensers

Usage of enhanced tubes in electric utility steam condensers have many advantages including smaller condenser size, additional electricity generation by lowered condenser back pressure, etc. In the present study, titanium corrugated tubes were tested for application to electric utility steam condensers. The tubes have relatively small corrugation heights and large corrugation pitches. In addition, the lowest helix angle is 18o, which is much lower than those of existing studies. The friction factor increased as corrugation pitch decreased and corrugation height increased. The penalty factor ranged from 1.09 to 1.89. The heat transfer coefficients showed similar trend with that of the friction factor. The enhancement factor ranged from 1.05 to 1.46. Exiting correlations did not adequately predict the present friction factors and heat transfer coefficients. The reason was attributed to the geometric difference of the present corrugated tubes (large p/e and small e/D-i). New correlations were developed, which predicted the present data within +/- 20 %.