​Analysis of Internal Flow Conditions in Multi-Blade Fan Impellers

Analysis of Internal Flow Conditions in Multi-Blade Fan ImpellersThose who have utilised multi-blade fan installations must recognise that the multi-blade impeller constitutes one of the critical components of the equipment. Moreover, during operation, the flow within the multi-blade impeller represents a highly complex back-pressure process. Indeed, the high rotational speed of the multi-blade impeller and the intricate geometry of the blade passages exert a profound influence upon its flow characteristics. The primary motivation for investigating this aspect is to enhance the performance of multi-blade fan units, utilising this research to further optimise their operational efficiency. Due to specific pressure differentials during operation, secondary flows frequently occur within the blade passages facing the negative pressure side of the multi-blade impeller. This phenomenon may adversely affect the machine's operational efficiency. Additionally, the operational noise of multi-blade fan units can sometimes become excessive. Consequently, to mitigate this situation, boundary layer control methods have emerged as a significant research focus in recent years, aiming to sequentially enhance impeller performance. Relevant experiments indicate that as flow rates decrease, the jet wake structure of the propeller intensifies. Through years of dedicated effort, substantial progress has been achieved. Notably, research into internal flow within multi-bladed fan propellers has made remarkable strides. Moreover, highly satisfactory results have been achieved in practical applications. Research in this area remains ongoing, with confidence in attaining further improvements. Indeed, when investigating the internal flow of multi-bladed fan impellers, our primary research methodology employs steady-state calculations. It is anticipated that subsequent enhancements in technical capabilities will foster a more comprehensive understanding of unsteady flows within turbomachinery and their underlying mechanisms.