This paper presents the transformation cycle of condensation
and transit evaporation regimes of sprayed water droplet phase
in humid gas in the context of heat utilization from removed
biofuel combustion products.
A mathematical model based on the heat flow balance on the
droplet surface was applied. It combines droplet internal heat
transfer and external heat transfer and phase transformation
problem solutions. The unsteady temperature field gradient of
the droplet is described according to analytical model of heat
spread by conduction and radiation in a droplet, while the
influence of heat convection is evaluated by the effective heat
conductivity parameter. In the droplet, local radiation flow is
defined based on spectral radiation absorption in a semitransparent
sphere model. Variation of droplet heat and mass
transfer parameters is defined by droplet surface instantaneous
temperature that is selected according to iterative numerical
scheme operated by the fastest descent method. For this scheme,
the requirement is raised that relative error between
instantaneous calculated heat flows that flow in and from the
surface should not exceed five-hundredths percent. The essential
role of the droplet slipping factor upon interaction of transfer
processes in transformation regime of the condensation phase in
gas flow was highlighted.
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.