Influence of the air diffusers on human thermal comfort inside vehicles – a review article

The time spent by vehicle occupants in traffic has grown significantly in the last decades. Improving the thermal comfort of the people inside vehicles has gained a lot of importance in the last years both from subjective and objective reasons. The airflow passing through the air diffusers will directly affect the thermal state of the users through its temperature, velocity, and turbulence. A solution to improve the cabin ambiance is to uniformize the airflow inside vehicle through a better mixing between fresh air and ambient air. The automotive industry through its vehicles produced in the last years does not seems to consider this innovative strategy. An idea to improve the air mixing by passive means is using innovative air diffusers which have the capacity to entrain more air than a regular air diffuser. The lobed shaped cross orifice was found to entertain more air than a regular nozzle and derived from this shape more geometries emerged. A good compromise for the air diffuser design in vehicle was found to be the lobed ailerons. The entrainment in the case of the airflow issued from the air diffuser with lobed ailerons it was found to be greater than in the case of the standard air diffuser with straight ailerons.