Dropwise condensation of humid air - Experimental investigation and modelling of the convective heat transfer. (June 2020)

• Record Type: Journal Article
• Authors: Eimann, Ferdinand; Zheng, Shaofei; Philipp, Christian; Omranpoor, Amir H.; Gross, Ulrich
• Is Part Of: International journal of heat and mass transfer. Volume 154(2020)
• Publication Date: 2020-06
• Subjects: Dropwise condensation -- Humid air -- Heat transfer -- Heat and mass transfer analogy; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2020.119734
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: Experimental investigation of dropwise condensation heat transfer out of turbulent humid air flow. Heat transfer measurements are accompanied by visual evaluation and quantification of the droplet pattern. A novel modeling approach leads to a correlation predicting the experimental data with rather good accuracy. Abstract: In this investigation dropwise-condensation heat transfer of out of a turbulent flow of humid air is experimentally investigated. The test section consists of a horizontal channel, sized 12 × 32 × 750 mm. The condensation takes placed on a 9 × 6 mm sized section of the vertical channel wall. A model based on the analogy of heat and mass transfer - previously used in the context of filmwise condensation - is adopted in order to describe the data obtained for varying bulk Reynolds numbers (3000–22000), temperatures (36 ∘ C–55 ∘ C) and relative humidities (36%–55%). Modifications are made in order to capture the effect of fog formation within the mixture and the enhancement of the area available for heat transfer induced by the droplets on the substrate. The formulation of the model is intended to be easily adoptable to other geometries, boundary conditions, types and orientations of the substrates. Previous investigations of this group were focused on the thermal resistance of the condensate. Based thereon, the present modelling completes the former approach, resulting in a model capable of predicting the total heat transfer coefficients of dropwise condensation from humid air. The predictions are validated using own experimental data as well as external data.