Ansys Fluent’s solidification/melting model can account for the presence of an air gap between the walls and the solidified material, using an additional heat transfer resistance between walls and cells with liquid fractions less than 1. This contact resistance is accounted for by modifying the conductivity of the fluid near the wall. Thus, the wall heat flux, as shown in Figure 15.2: Circuit for Contact Resistance, is written as
 | (15–23) |
where 
, 
, and 
are defined in Figure 15.2: Circuit for Contact Resistance, 
is the thermal conductivity of
the fluid, 
is the liquid volume fraction, and 
is the contact
resistance, which has the same units as the inverse of the heat transfer
coefficient.
