Influence of the spectral solar radiation on the air flow and temperature distributions in a passenger compartment

The present study aims to investigate spectral solar radiation effect on the air flow and temperature distributions in a passenger compartment. For achieving this goal, transmittance and reflectance for different glass types were measured to analyze the spectral characteristics of windshield by using a spectrophotometer. Using the measurement data, extensive CFD simulations were conducted for three different cases by using the commercial CFD software (ANSYS Fluent 13.0) based on the discrete ordinates method in solving radiative energy transfer equation. It was found that 99% of solar energy intensively existed in the wavelength range between 280 nm and 2500 nm on the basis of the standard solar spectrum (ASTM G173). In particular, strong deflection of air flows were observed near the front seat and it could generate higher mixing region due to the complex vortical flows. Considering the spectral effect, the predicted temperature in the compartment increased by approximately 3 °C, resulting from spectral variation of transmittance and reflectance. Therefore, the spectral solar radiation effect should be considered for more accurate prediction of air flow and thermal fields in the compartment.