BT-34 Transition Boiling in Vertical Tubes
For vertical intube flow boiling, two types of transitions from wet-wall wall boiling to dry-wall heat transfer occur in different flow regimes: transition boiling (from nucleate flow boiling to film boiling) and dryout (from annular flow boiling to dry-wall mist flow evaporation). This report focuses on transition boiling and proposes a method for the transition boiling heat transfer coefficient. The proposed method predicts the trend more accurately and greatly improves prediction of our vertical thermosiphon reboiler data, taken with portions of the tubes in film boiling. Using the proposed method, engineers can design with much greater confidence reboilers and vaporizers with part of the tubes in film boiling.