Hydrocarbon mixture condensation inside horizontal smooth tubes

The results from an experimental investigation of condensing zeotropic mixtures of hydrocarbons inside horizontal tubes are presented. The trends in heat transfer coefficient with temperature glide, saturation pressure, concentration, mass flux, and quality and tube diameter are discussed with reference to the changing thermodynamic and physical phenomena across the condensing conditions. The modeling techniques most commonly used to account for the non-equilibrium conditions and changes in the bubble and dew point temperatures affecting the condensing heat transfer coefficient are assessed. The degradation in heat transfer coefficient due to mixture effects is most significant at large temperature glides and in the larger tube diameter, and is least significant at higher mass fluxes. The data are analyzed using the Silver Bell Ghaly approach as well as the Colburn and Drew framework. The study provides insight into the behavior of zeotropic mixtures during condensation. The conditions that results in the largest concentration changes and cause the greatest degradation in the heat transfer rate are outlined. (C) 2016 Elsevier Ltd. All rights reserved.