Numerical Investigation of Air Supply Distribution, Flow Regimes, and Thermal Patterns inside a Private Bus

摘要

Vehicle aerodynamics has been the subject of extensive research, with a heavy emphasis on the vehicle. Heavy vehicles, such as trucks and buses, have undergone aerodynamic studies in recent years to reduce drag and improve fuel economy 1. In this study, the distribution of air conditioning in the cabin of a passenger bus was investigated by discussing the factors that influence in attaining the desired thermal comfort values such as temperature distribution, relative humidity ratios, and air velocities inside the bus. The research was conducted on three different cases. In this study, different types of air-conditioning (AC) outlets-linear grills, slots diffusers, and gaspers-were used, and the effect of each outlet on temperature distribution, air velocities, and relative humidity ratios within the bus was investigated. In all three cases, the inlet air velocity was set to 0.8 m/s, and the return air was combined in the middle of the bus. Finally, comparisons were made between the cases to determine the best case for achieving the thermal comfort rates inside the bus. The results demonstrated that the slots diffuser could not be used in the bus air conditioning because of the presence of turbulences and swirl motions which impeded the flow of cold air. The gasper is the best flow outlet in the air distribution inside the cabin that achieves the required thermal comfort for the passengers because the flow is laminar and there is no turbulence, resulting in a good mixing between the conditioned air and the air inside the bus cabin and a good distribution of temperature inside the bus.