| Axial fans are the most widely used impeller machinery in engineering.In the upgrading of some products,due to the limitation of molds,the hub ratio and the size of the fan are limited,which brings about the design and performance optimization of the fan blades a certain difficulty.In this paper,the optimization design of the fan blade modification is mainly based on the prototype straight blade fan,and the numerical simulation of the fan using forward-swept blades and forward-curved blades after the modification is carried out,and the forward-swept blade fan with better performance is carried out.Experimental Study.Based on the new design,this paper uses CFX software to study the internal flow field,blade surface and space pressure field,fan noise,fan performance,etc.of the fan under various conditions.On the basis of comprehensive comparison,the forward-swept blades were selected to conduct experiments on the airflow pulsation,vibration,and noise of the fan,and to explore the relationship between airflow pulsation,noise and vibration in the flow field.The main work of this paper is as follows:1.On the basis of the prototype straight-blade fan,the forward-swept and forward-curved blades were designed and modeled.2.Carry out numerical simulation research on the designed forward-swept blade fan.Compared with the traditional straight blade,the forward-swept blade can obtain better aerodynamic performance and a wider range of stable operation.3.In order to achieve the performance of forward sweep under the condition of as far as possible to meet the strength of the blade,this paper has carried out an attempt to offset the blade,and simulate the aerodynamic performance and strength of the offset blade after modeling.It is found that the offset installation of the forward-swept blade will avoid the increase in blade stress caused by the centrifugal force caused by the forward-swept,but it will lead to a sharp drop in the aerodynamic performance of the forward-swept blade.4.A numerical simulation study was carried out on the designed forward-swept blade fan.Under the plan of 8° forward bend,the efficiency change was not large,and only the noise dropped from 108.8db to 106.7db.However,the total pressure is about10-20 pa drop,and the forward curved blade in the modified design has no obvious performance advantage.5.The noise,vibration,and air flow pulsation of the fan with forward-swept shaped blades are experimentally studied.The fan has the consistency of vibration,air pulsation and noise in the main operating area.For the fan studied in this paper,the amplitude of each item is the largest at 2.5 times the passing frequency of the fan(320Hz);as the flow decreases,the amplitude of the fluctuation is The large frequency changes to the low frequency,and the noise of the fan gradually changes from discrete noise to turbulent noise.The optimization research work of the fan under limited conditions in this paper provides a certain reference for similar projects.It proves that the forward sweep and forward bend modification of the fan can improve the performance of the fan to a certain extent.The relevant experimental research of the modified fan is carried out.It also provides guidance for fan design,noise reduction,and fault diagnosis.The paper contains 44 figures,3 tables,and 54 references. |
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