Numerical Analysis of a Centrifugal Fan for a Road Sweeper

Road sweeper is the widely-employed machine to clear up garbage and dust on streets. Its performance has profound influence on the reduction of fuel consumption and hence CO₂ emission. The key component of a road sweeper is a centrifugal fan which produces suction force for clearing. Therefore, the performance of this device has direct impact on fuel economy of the machine. This paper targets at the performance analysis of a centrifugal fan in a commercial road sweeper. Firstly, the performance and flow field of the centrifugal fan are analyzed by computational fluid dynamics (CFD) method. The breakdown of the flow loss in the fan shows that the volute and the impeller are major components contributing to flow loss in the fan. The flow at the inlet of the impeller is highly distorted due the interaction among the asymmetrical inlet duct, the leakage and the volute tongue. Because of the interaction, flow passages near the tongue are the ones with the highest flow loss. Moreover, the flow velocity entering the volute is considerably high which thus results in high flow loss in the volute. Finally, based on the flow field analysis, an inlet duct with round shape is designed preliminarily and simulated together with the centrifugal fan. The results show that the efficiency can be improved by more than 4% compared with the original configuration due to the alleviation of the interaction.