BT-23 Evaporation inside Horizontal Enhanced Tubes
This report summarizes experimental work and design methods available for evaporation inside horizontal enhanced tubes. The types of enhancements addressed are microfin tubes, tubes with twisted tape inserts, and corrugated (or fluted) tubes. Fluids covered are refrigerants and hydrocarbons (only propane); azeotropic mixtures and zeotropic mixtures are also addressed. In addition, refrigerant-oil (very wide boiling range) mixtures are discussed at length. A significant body of experimental data is available for microfin tubes but much less for the other enhancements. Heat transfer and two-phase pressure drop prediction methods are presented for the various enhancements, where available.