Impact of realistic boundary conditions on CFD simulations: A case study of vehicle ventilation

Abstract

In recent years, the accurate numerical simulation of airflow in vehicle cabins has become increasingly important for optimizing thermal comfort and energy efficiency. This study investigates the impact of realistic boundary conditions on Computational Fluid Dynamics (CFD) simulations for vehicle ventilation systems. The research integrates detailed HVAC duct data to provide a more accurate representation of airflow characteristics, diverging from conventional approaches that often assume uniform inlet conditions. Using a 3D CFD model, airflow patterns were simulated under two scenarios, comparing a case with simplified boundary conditions to one incorporating detailed duct geometries and realistic conditions. The numerical model was validated using experimental data, including Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV) measurements. The findings reveal that using realistic boundary conditions significantly enhances the accuracy of airflow predictions, particularly regarding velocity distribution and thermal comfort. This work highlights the critical role of detailed boundary condition specification in improving the reliability of CFD simulations for vehicle ventilation and other personalized ventilation applications.