Influence of flow and thermal characteristics on thermal comfort inside an automobile cabin under the effect of solar radiation

Abstract

Present work describes the thermal comfort of the driver in an automobile cabin under the effect of solar radiation for different cooling jet directions. Three-dimensional transient cooling simulations of the in-cabin flow and heat interactions have been carried out using commercial solver ANSYS Fluent 18.1. The surface to surface (S2S) radiation model embedded within the solver has been employed to simulate the internal conditions of radiative heat transfer. The transient behavior of the flow inside the cabin has been brought out using Fourier spectra of velocity signals. The spatial distributions of temperature and velocity for different values of driver-side vertical guide vane angle have also been presented. The interaction between cooling jets from the air-conditioning vents with air inside the automobile cabin has been illustrated using iso-Q surfaces describing the vortex structures in the flow field. Variation of bulk average temperature with vertical guide vane angle is also reported in this study. The thermal comfort of the driver has been evaluated using Equivalent Temperature (ET) and Effective Draft Temperature (EDT) for different values of vertical guide vane angles. The ET and EDT values corresponding to different locations on the body of the driver have been compared to bring out the relative significance of draft and radiative heat transfer on the thermal comfort inside an automobile cabin. Optimal guide vane angle corresponding to enhanced mixing and thermal comfort has also been identified.