ABSTRACT
A significant portion of all heat exchangers employed in the process and power industries are used to boil pure or liquid mixtures. Many of these heat exchangers involve boiling heat transfer, and hence two-phase (vapor-liquid) cross-flow on the shell-side of horizontal tube bundles. In the chemical and petroleum industries, such equipment is commonly referred to as ‘reboilers,’ or by the more general term, ‘process vaporizers.’ While the single-phase heat transfer correlations available for predicting thermal performance in tubular heat exchangers are typically accurate to within ±30%, the accuracy becomes worse for reboilers, as two-phase heat transfer is often very difficult to estimate, especially with mixtures of several components. According to a visual study by Comwell et al. of a thin slice of a reboiler, the core of the bundle experiences nearly a vertical two-phase flow, and the void fraction is the highest near the top of the bundle.
