Validation of 3-D Passenger Compartment Hot Soak and Cool-Down Analysis for Virtual Thermal Comfort Engineering

Simulation of passenger compartment climatic conditions is becoming increasingly important as a complement to wind tunnel and field testing to help achieve improved thermal comfort while reducing vehicle development time and cost. Thermal analysis of a passenger compartment involves not only geometric complexity but also strong interactions between airflow and three modes of heat transfer, namely, heat conduction, convection, and thermal radiation. The present full 3-D CFD analysis takes into account the geometrical configuration of the passenger compartment including glazing surfaces and pertinent physical and thermal properties of the enclosure with particular emphasis on glass properties. This CFD analysis is coupled with a thermal comfort model in the Virtual Thermal Comfort Engineering (VTCE) Process that was described in [1]. The thermal comfort model is based on a physiology thermal regulation model of 16 body segments and each segment is modeled as four body segments and a clothing layer. A major challenge of VTCE is the prediction of the thermal environment around an occupant in a passenger compartment. The present full 3-D CFD analysis of hot soak and cool-down simulations demonstrated excellent agreement with available experiment data for a simplified passenger compartment. The combination of CFD with thermal comfort simulation allows for the exploration of different climate control strategies as they relate to human thermal comfort in a quick and inexpensive manner.