The combined heat and mass transit processes of water droplets in biofuel technologies

Abstract

The number of thermal technologies is based on water droplets heat and mass transfer processes. In this paper droplets heat transfer and phase transformations were modelled in the context of water spraying in humid flue gases application for biofuel combustion technologies. Droplets warming is defined when its surface instantaneous temperature is calculated according to an iterative numerical scheme, which is based on heat fluxes balance that flows in and from the droplet surface. The transfer processes interaction is taken into account. The influence of spraying water temperature, biofuel flue gases temperature and its humidity as well as droplets heating process impact on spraying water droplets transit phase transformation regimes were highlighted. Technological cases of water spraying in a biofuel furnace and heat recovery from removed flue gases were highlighted. In condensing economizers at recovered flue gases sprayed droplets heat transfer conditions are defined by their slipping factor in flue gases, while in the case of biofuel combustion in the furnace, droplets slipping and its surrounding radiation factors are equivalent.