Abstract
KEYWORDS – Automotive Engine Cooling Fan, Fan Noise, Computational Fluid Dynamics, Lattice Boltzmann Method, PowerFLOW
ABSTRACT – Low-speed axial fans provide the necessary airflow for engine cooling through a car's heat exchangers, especially when the vehicle operates at low speeds or idle. These fans are used to maintain engine temperature to guarantee best operating conditions. However, they generate flow-induced noise often perceived by consumers as poor vehicle quality. As a consequence, the noise comfort related to fans when designing a vehicle is gradually becoming more important for the automotive industry. Many numerical studies have attempted to predict the aerodynamic noise levels of fans and tried to understand the noise generation mechanisms associated to rotating bodes using traditional numerical methods. However, they appear to still be insufficient in terms of accuracy and turnaround times. In this study, a fully transient and compressible numerical solver based on the Lattice Boltzmann Method is used to predict the flow and noise levels of two automotive cooling fan module configurations, and simulation data is successfully compared to experimental results. In addition, an innovative Flow-Induced Noise Detection (FIND) capability is used to process the transient flow results to provide information on the location and the intensity of the flow noise sources. These results are used to guide modifications of the design fan in order to reduce the radiated noise levels.