| Multi-blade centrifugal fan is widely used in air-conditioning due to its large flow coefficient,high pressure coefficient,low noise and small size.With the development of science and technology and the improvement of people’s living standards,the high efficiency and low noise of multi-blade centrifugal fans have become the main goal of fan design.CFD plays an important role in the aerodynamic design and noise control of centrifugal fans,which can greatly shorten the design cycle.In this dissertation,a variety of new structures of impeller and volute are proposed for the comprehensive performance improvement requirements of a multi-wing centrifugal fan for airconditioning system.The effects on the aerodynamic performance and noise of the fan are analyzed through experiments and numerical simulations.The research contents are as follows:(1)The influence of the impeller structure on the performance of the multi-blade centrifugal fan is studied.The efficiency of the fan,the uniformity of the inlet and outlet speed and pressure distribution are numerically simulated under different blade exit angles,blade distribution patterns,number of blades and impeller installation position.The results show that the blade form and the impeller installation position have a significant impact on the efficiency of the fan,but the flow field uniformity is relatively less affected.(2)Three kinds of multi-blade fan volute structures and profiles are proposed,and the effects of different volute structures on the aerodynamic performance and noise of the fan are studied.Numerical simulation of flow field distribution,broadband noise on the volute and blade surface of the fan,and discrete noise at the monitoring point is conducted.The numerical simulation results are verified by experiments,and the aerodynamic performance and noise of different volute structures are compared and analyzed.The research results provide reference for the selection and design of the volute form for multi-blade centrifugal fan.(3)The adaptability of different volute structure forms to different aerodynamic performance and noise requirements is discussed.The volute structure and the rapidly formable impeller structure is selected.A new scheme of high-efficiency low-noise multi-wing fan structure is given,and the performance and noise of the new structure are numerically predicted.The results show that the overall performance of multi-wing fans has been effectively improved.Based on numerical simulation and experimental research,this paper analyzes the main impeller structure parameters and volute form that affect the efficiency and noise of a multi-blade centrifugal fan,and proposes a high-efficiency and low-noise multiwing fan structure that meets the requirement of rapid prototyping process.The results can be used to support the improved design and development of a series of multi-blade centrifugal fan products for air conditioning systems. |
