Engineering Approach for Noise Reduction for Automotive Radiator Cooling Fan: A Case Study

The automotive radiator cooling fan is a device that can help regulate the engine temperature by moving air through a radiator. The common side effect of the radiator fan is the generation of flow-induced noise, which is a source of community noise, especially when the fan is operating in high-speed mode. In this paper, the detailed experimental studies for recognizing the source of the fan noise on one of the IKCO vehicles are carried out. Based on the experimental data, fan speed optimization and redesigning of the front bumper are selected as the main modification to the vehicle to reduce the noise level. The results revealed that the fan noise level could be dropped by about 7 dB. Since the applied solutions for noise reduction have impacts on the performance of the engine cooling system, a computational fluid dynamics (CFD) approach is conducted to study the side effects of applied modifications on the cooling system performance. The numerical model accurately predicted the drag coefficient with differences of less than 2%. Analysis of the air velocity distributions and pressure coefficients from the steady model showed that the front bumper structure significantly affected the cooling performance. It is demonstrated that by manipulating the fan, radiator, and front bumper, simultaneous improvement of the noise level and the cooling performance can be achieved.