Study On Flow Characteristics Of Axial Flow Fan

Axial fans are widely used in many fields because of its characteristics which has large flow and low wind pressure.The consumption of energy for axial fan is high while the utilization rate of energy is low.Compared to other developed countries,The efficiency of the domestic axial fan is low which has become the reason for restricting the rapid development of the fan industry in our country.In view of the high energy consumption and low efficiency of current axial fan in China,This paper begins with the design of axial fan,to seek the best working condition of axial fan through studying on the change of efficiency and pressure of axial fan under different parameters.Through this method,the flow characteristics of the axial fan are found and studied.In the early stage of modeling,First of all,according to the requirements of a certain operating condition,the design of axial flow fan is carried out,I got its performance by numerical simulation and then I modify the different parameters.To study its effect on the performance of axial fan,The flow characteristics of axial flow fans under different design elements are obtained.In the case of a small change of the static pressure,I reduce the power consumption of the axial fan to meet the needs of design.In the process of finding the optimum condition,I use a three-dimensional numerical simulation to study the internal flow and analysis flow characteristics of axial fan under different parameters.In the process of 3D modeling,The CLARK_Y and C4 airfoil were quickly built by combining EXCEL database with SOLIDWORKS.The performance of axial flow fan such as flow-efficiency,flow-pressure head is studied by FLUENT software,and analyzed the flow situation of the impeller,rear guider and the fluid behind the rear guide.Through the analysis of the flow characteristics of axial flow fan under different design factors such as speed,blade number,blade installation angle,blade tip clearance and wheel hub ratio,it is found that: When the fan speed increases from small to large,the inlet air angle and blade resistance decrease,and the power of the fan decreases first.When the speed increases to a certain extent,the impeller wall loss,secondary flow loss and the vortex loss of blade tip clearance increase,and aerodynamic performance reduction;The total pressure performance and efficiency of blade number 7 are higher than that of blade number 5 and 9.With the increase of blade installation angle,the lift and resistance will increase simultaneously,and the energy loss of air fluid will increase.As a result,the efficiency of axial fan is reduced,and the corresponding blade installation angle and blade root angle of attack are obtained when the fan efficiency is maximum.The smaller the tip clearance,the higher the efficiency of axial flow fan,and the more stable internal flow is.The total pressure efficiency of axial fan increases first and then decreases with the increase of hub ratio,and the hub ratio is obtained when the average efficiency is maximum.