Forward Curved Blade Distortion Design And Performance Analysis Of Multi-Blade Centrifugal Fan

Multi-blade centrifugal fan as a kind of universal machine,with its high pressure coefficient,large flow coefficient,low noise has been widely used in civilian areas,but its drawback is the low efficiency.For the range hood,we often hope that under the same pressure,the better effect of oil smoke.In this paper,the flow rate is chosen as the optimization objective,and the numerical simulation method is used to three-dimensional optimization design a impeller in order to improve the fan flow and achieve the purpose of energy saving and efficiency increasing.In this paper,a multi blade centrifugal fan as the research object,in order to improve the multi conditions of fan impeller flow,using the method of orthogonal experiment on the impeller,deterlowe the optimal scheme.Verify and analyze the flow characteristics of the optimal scheme.(1)Numerical simulation and experimental verification of original centrifugal fan:By using the Fluent to simulate the original multi-blade centrifugal fan,this paper analyzes the flow characteristics of the fan in the most efficient and large flow conditions.The results show that the flow characteristics is very complicated.By the volute structure type,blade velocity distribution along the circumferential direction are not affected;by the inlet state,flow in shroud is not ideal,there are secondary flow;by the inlet angle,blade suction surface separation vortex.The simulation results are compared with the experimental results to verify the reliability of the simulation method.(2)Forward curved blade distortion design and performance analysis:This paper puts forward the concept of blade twist design,deterlowes the three optimization factors : reverse direction,reverse position and torsion angle.At the same time,designs the distortion scheme by orthogonal test,numerical calculation of three conditions of traffic,select super transitive approximate method for function optimization,in order to flowto obtain the optimal scheme optimization.the final results showed that the optimized model of improved flow fan low flow condition and highimum efficiency condition,And the optimized model improves the flow separation of the leading edge of the blade and the irregular flow of the boundary layer of the blade suction plane.