An Efficient Numerical Approach for Evaluating the Windshield Defogging Time

A windshield defroster has an important roll of clearing up fogged window glasses of a vehicle by blowing out warm air. In simulations parameters that affect the defogging time are the velocity, humidity and temperature of the flow from a defroster nozzle. However, individually varying all the parameters and investigating their effects will lead to many computing cases and long runtime. An approach that can considerably reduce calculation time is proposed. The approach is dictated by two key-steps: 1) First, steady-state velocity distributions for several different defroster flow rates are calculated; 2) Secondly, based on the pre-calculated velocity fields, the defogging time is estimated. This approach is compared to the conventional method that always couples all the parameters in transient calculations.