Steam Condensation and Tube-Side Heat Transfer of Titanium Corrugated Tubes

Abstract

In the present study, two titanium corrugated tubes (22.2 mm outer diameter and 0.5 mm tube thickness) having widely different corrugation pitch (2.1 and 22.1 mm) and having the same corrugation depth of 0.2 mm were tested at the steam pressures (from 5 to 10 kPa) representative of an actual electric utility condenser. Small corrugation depth of 0.2 mm was chosen from the concern of tube-side fouling and sponge ball cleaning. Significant enhancement of condensation heat transfer is noted, especially for 2.1/0.2 tube. The heat transfer enhancement ratios are 4.0 and 2.76 at 5 and 10 kPa, respectively. The tube-side heat transfer enhancement ratios are 1.08 for the 2.1/0.2 tube and 1.03 for the 22.1/0.2 tube. The tube-side pressure drop penalty factors are 1.56 for the 2.1/0.2 tube and 1.07 for 22.1/0.2 tube. Tube-side heat transfer may be further enhanced by increasing the corrugation height. However, concerns on fouling or corrosion should also be considered.