Numerical Investigation on Performance Based Methodology for Developing Vane Design of AC Duct

Airflow directionality in a vehicle cabin is one of the concerns of car owners, researchers, and vehicle manufacturers. After exposed/parked in hot ambient condition for a long time, HVAC system normally takes few minutes to cool down and reach an acceptable cabin temperature for the passenger comfort. To ensure proper airflow distribution inside the cabin, the AC duct & vanes ability to direct airflow must be evaluated. Objective of this work is to propose a methodology for developing the vane design of AC system duct using CFD approach. Two different goals are attempted. Firstly, the effect of horizontal and vertical vane angle on airflow directionality is investigated with DoE approach. Then factors influencing the airflow directionality are investigated using factorial study approach. CFD based factorial analysis (L₉ orthogonal array) was conducted using three components at three levels. The impact of number of horizontal vanes, number of vertical vanes and distance between them on the pressure drop and face level velocity are investigated. One of the parameters required to freeze vane design is attaining higher face velocity and lower vent pressure drop. New methodology is proposed in this work to choose the required number of horizontal and vertical vanes of automotive AC system duct/vent assembly based on their airflow directing ability.