RB3-6 Update of the RTF Program Modification 7.05 for Better Prediction with Wide-Boiling-Range Mixtures

J. W. Palen

The RTF Computer Program methods, Modification 7.05, have been updated in several areas to produce more reasonable performance, especially for the extreme case of very wide-boiling-range mixtures with multiple components. The most significant changes are the following.

  1. Use of a new average boiling range concept for multicomponent mixtures based on new data, as described in HTRI Report BG-1-7.
  2. Extension of a limit for the wide-boiling-range correction to the film boiling critical DT so that this criterion is no longer too conservative for mixtures with a boiling range greater than 100 °F.

In addition, the nucleate boiling suppression factor was revised to account for results of the newly added nucleate boiling correlations; predictions in the bubble and slug flow regimes were made less conservative; and a natural convection component was added to the nucleate boiling mechanism, as recommended in the HTRI Design Manual.

Further ""housekeeping changes"" included improvement in the exit pipe velocity warning message selection, removal of old coding no longer referred to by the program, and addition of more comments.