Thermal comfort assessment of the cabin driver exposed to impinging jet ventilation based on Fiala and equivalent homogeneous temperature methods

This paper simulates and compares the impacts of two ventilation methods on the flow field and temperature distribution in a car cabin, presenting an impinging jet ventilation (IJV) system for automobile cabins. The simulation's accuracy is verified by impinging jet experiment results and prior simulation studies. The Fiala thermoregulation model and equivalent homogeneous temperature (EHT) model are used to assess the driver's thermal comfort. The results show that, compared to traditional dashboard-dominated ventilation, the IJV system significantly alters the cabin flow field by increasing velocity and promoting uniform mixing. Airflow around the driver is enhanced, temperature distribution is more even, and local high temperatures near the driver are reduced. Vertical and longitudinal temperature variations in the cabin decrease markedly, and temperature differences in the driver's clothing and skin are lowered. Heat perceptions at different body parts move closer to neutral, as indicated by the EHT model. Additionally, the Fiala predicted percentage dissatisfied and Fiala dynamic thermal sensation drop by 14.34% and 13.56%, respectively, significantly improving thermal comfort.