A three dimensional analysis program for the windshield defrosting phenomenon has been developed. The inside mean flow field is first obtained by solving the Reynolds averaged Navier-Stokes equations that incorporate the nonlinear k- ε turbulence model. The unsteady calculation for the temperature distribution, that involves the conjugate heat transfer and the phase change of the frost, is then carried out to examine the melting pattern of the frost on the windshield. The unsteady temperature field and the melting pattern are presented for four defroster nozzles on the dashboard. The nozzle width are varied, while keeping the flow rate constant, to see its effect on the result. The narrow nozzle, that accompanies higher velocity, is found to be more effective. The effect of hot air injection through A pillar slots is also examined.
