Optimization of the electric bus radiator design in terms of noise emissions and energy consumption by computational fluid dynamics

The paper presents the numerical optimization of an innovative radiator for use in electric buses in terms of energy consumption and noise emission. Computational fluid dynamics simulations were performed. The flow of the cooling medium was modeled using the RANS method. The two-equation k-ɛ turbulence model, the heat transfer model and the acoustic model were used. According to the research results, the separation of the air stream in individual fan sections contributes to the improvement of energy efficiency and reduces noise emissions. As a result of the simulation, it was found that the best solution in terms of noise emission as well as the occurring flow phenomena caused about a 2 dB decrease of maximum values of the noise level and allowed the equalization of the cooling medium velocity (prevailing velocity range between 4 and 9 m/s). The results of the simulations were verified under laboratory and field conditions, showing a very good convergence of the model with the results of the experiments (i.e. the maximum noise level was estimated at 57 dB, under measurement conditions for the same operating point at 59 dB) while maintaining the baseline energy demand, which indicates a new approach in the method of shaping internal elements of electric vehicle coolers.