Condensing droplet behaviors on fin surface under dehumidifying condition: Part I: Numerical model

• Numerical model of condensing droplet behaviors was developed.
• Model of mass transfer for droplet formation was developed.
• Model of mass transfer for droplet growth was developed.
• Effects of operation conditions and fin geometry were analyzed.

The condensing droplet behaviors on the fin surface have a significant influence on the performance of fin-tube heat exchangers under dehumidifying conditions. A numerical model for predicting the condensing droplet behaviors was developed. In the model, the mass transfer rates during droplet formation and growth processes and the contact angles of the droplets were introduced into the control equations as source terms; the mass transfer rates were predicted based on the species conservation on the fin and droplet surfaces; the contact angles controlling the droplet movement were predicted based on the modification of existing model by reflecting the effect of air flow force on the droplet movement. Based on the proposed model, the effects of operation conditions and fin geometry on heat and mass transfer characteristics were analyzed. The experimental validation of the proposed model will be performed in the Part II of the present study.