CFD Simulations of an Automotive HVAC Blower: Operating under Stable and Unstable Flow Conditions

Computational Fluid Dynamics (CFD) is heavily used in automotive HVAC industry in order to reduce the time and cost in design, optimization, and development of different components [2]. Correct prediction of the aerodynamic characteristics of an HVAC blower is crucial in development of the accurate CFD models for the whole HVAC system. CFD models are extensively used in the optimization of both thermal and airflow characteristics of automotive HVAC [3, 4 and 5].

In this study we have performed CFD simulations for different blower operating conditions in order to assess the CFD results in prediction of the aerodynamic performance in an automotive HVAC forward curved (FC) centrifugal blower. The realizable k-ε turbulence model was used on the Reynolds Averaged Navier-Stokes approach to model complex flow field properly.

Steady state analysis showed good correlation for the stable flow conditions (high airflow and low pressure), whereas this approach showed large discrepancies for unsteady flow conditions (low airflow and high pressure). By a transient simulation and realizable K-ε model, the CFD analysis showed good correlation compared to experimental test results.