CFD Analysis and Validation of an Automotive HVAC System

Investigation of fluid flow for three different modes of operation of an automotive heating ventilation and air conditioning (HVAC) system is carried out in the present work. The modes considered are: face mode, defroster mode and foot mode. The performance of the HVAC system is judged by parameters like air discharge rate at cabin level, pressure drop through the system, uniformity of the air flow at the outlet faces and distribution between different duct outlets. All these parameters are predicted by Computational Fluid Dynamics (CFD) analysis. Multiple reference frame (MRF) model is used to simulate the steady state flow through the rotating blower. Porous medium model is used to simulate the flow through the evaporator and heater. The standard k-▪ model is used to consider the turbulent effect of air flow. Comparison between CFD and experimental results shows that the cost and time incurred in the HVAC system development can be reduced drastically by incorporating CFD as a design tool.