MATHEMATICAL MODELLING OF FROST LAYER GROWTH IN A FIN-AND-TUBE HEAT EXCHANGER

In the paper a numerical analysis of heat and mass transfer during frost formation on a finand-tube heat exchanger has been performed. Frost layer formation significantly influences the heat transfer on heat exchanger fins. The numerical analysis of the frost growth enables predictions of the heat transfer resistance and the decrease of exchanged heat flux. A transient two-dimensional mathematical model of frost formation has been developed. The applied mathematical model has been defined using governing equations for the boundary layer that include air and frost sub-domains as well as a boundary condition on the air-frost interface. The mathematical model with initial and boundary conditions has been discretised according to the finite volume method and solved numerically using SIMPLER algorithm for the velocity-pressure coupling. As result of numerical calculations, time-wise frost thickness variations for different air humidities have been presented.