Experimental data is presented for mixture condensation within a wide composition range. Different aspects in the heat transfer deterioration of mixtures are discussed. The results serve to develop a novel superposition approach for the approximate calculation of mixture condensation heat transfer coefficients.

Abstract

Legal requirements for refrigerants necessitate a continuous development of these fluids, also focusing on mixtures. This article contributes three aspects to the ongoing research: (1) Experimental mean heat transfer coefficients were determined for the condensation of two novel zeotropic mixtures, hexamethyldisiloxane (MM)/octamethyltrisiloxane and ethanol/MM, gathered for filmwise condensation on a vertical tube. (2) Both mixtures were investigated with several compositions to provide a comprehensive understanding of the mixture effects. (3) The results were taken to develop a novel superposition approach to predict mixture condensation.