NUMERICAL AND EXPERIMENTAL EVALUATION OF AUTOMOBILE ENVIRONMENT DURING THE COOLING PERIOD

摘要

The thermal environment in an automobile, which is mostly dependent on convection and radiation, plays an important role in the automobile environment. Eventually, a good understanding of the flow behavior, heat transfer characteristics and the effect of air-conditioning on the windshield is important for clear visibility, occupants' comfort and safety. Numerical and experimental procedures were applied to determine a detailed description of the fluid flow and temperature distribution due to both windshield defrosters and instrument panel registers. The CFD results were compared with the experimental results at some particular position and on the inside windshield screen to verify the integrity of the CFD model. The locations of maximum velocity as well as the characteristics of the re-circulation regions are correctly predicted. The results show that the current design of the defroster nozzle delivers the maximum airflow in the vicinity of the lower part of the windshield. Highly nonuniform air blowing out of the defrost duct onto the windshield and nonuniform temperature was developed on the windshield. It was found that the temperature dropped down to a comfortable range within 15 minutes starting from the time at which the HVAC blower was switched on. When radiation is coupled with convection, the numerical predictions are in good agreement with the experimental investigations. The deviation between the numerical and experimental results is within 6%.