Search Results

Underhood environment of a passenger vehicle consists of critical components such as heat exchangers, engine, batteries and exhaust system with complex geometries. The exterior styling and the packaging constraints along with the aerodynamic requirements of minimal grill opening areas result in a compact and packed underhood. In such a restricted environment the volume of air flow entering the underhood reduces. The airflow management issues become even more severe in case the underhood environment is located at the rear end of the vehicle, away from the ram air zone available in front of the vehicle, as is the case in the present study. In recent times, a combination of 1D and 3D simulations have gained a high importance to conduct air flow and thermal simulations of vehicle underhood to understand the complex interactions of air flow velocities and temperatures.

In recent times, CFD (Computational Fluid Dynamics) simulation tools have been deployed by automotive OEMs for investigating Climate Control applications. In automotive vehicles, one such critical application is designing defroster nozzles with least flow resistance to carry hot air from HVAC (Heating Ventilation and Air Conditioning) unit and dispersing it onto the windscreen and side glasses to clear mist and ice. Clearance of windscreen and side window glass has a high importance for safe driving as mist and ice formation affects driver's visibility and comfort while driving in humid and snowy conditions respectively. In the present study, a half cabin model of the vehicle is prepared using commercial software package ICEM CFD as grid generation tool and CFD analysis is carried out using commercial software package FLUENT 6.3 to optimize the air flow distribution over the windscreen and then to predict defrost performance prior to full scale climatic wind tunnel tests.