Research On The Effect Of Blade Shape On The Performance Of Axial Fan

The contra-rotating axial flow local fan has the advantages of compact structure,large flow and easy adjustment,so it is widely used in coal mining.However,the low efficiency of the fan has caused a huge waste of energy.In addition,the actual operation process is accompanied by a large amount of noise.As the main work component of the axial flow fan,the blade is used to convert the mechanical energy of the rotating blade into fluid pressure energy and kinetic energy,which has a decisive effect on the performance of the fan.Research on the effect of blade shape on the flow field and sound field of the fan is of practical significance for improving the operating efficiency of the fan and reducing aerodynamic noise..This paper takes the FBD NO.8.0 mine-used contra-rotating local axial flow fan as the research object,and builds a B-type fan performance test platform to test the flow field performance of the fan.Inspired by the wing angle structure of the migratory bird's wings can improve the external flow of the wings.The bionic optimization design of wind turbine blades.The application of the orthogonal test method has the greatest impact on the four factors that have the greatest impact on the blade angle structure(the first-stage blade angle position s₁,the first-stage blade tip offset distance a₁,the second-stage blade angle position s₂ and the second-stage blade tip offset distance a₂)to screen,design a four-factor three-level orthogonal experiment,and obtain 9 groups of orthogonal experiment scheme groups.And using range and variance analysis to obtain the most efficient wing-angle blade fan at the rated flow point.After comparing the fan with the prototype fan,it is found that the wing-angle blade can effectively reduce the intensity and range of the vortex vortex,and make the optimal wing The total pressure and efficiency of the angular blade wind are increased by 7.24%and 1.76%at the rated flow,and the total pressure and efficiency are increased by 11.32%and 3.88%on average under the full flow condition.After exploring the sound field of the fan using the Broadband Noise method,it was found that the maximum sound power level of the first and second blade trailing edge regions of the optimal wing angle blade fan was reduced by 0.17%and 1.62%respectively compared with the prototype fan..And using the fluid-structure coupling(FSI)method to check the blade strength,the maximum equivalent stress on the primary and secondary blades of the optimal wing angle blade fan has been reduced by13.94%and 2.51%,and the amount of deformation has been reduced respectively.52.22%and 34.13%.In the leading edge part of the blade from the tip to the button 1/3 section,a leading edge serrated structure of different sizes is set up to optimize the structure of the blade.The numerical calculation of each group of serrated leading edge blade fans is carried out.After comparison with traditional fan,it is found that the serrated leading edge blades with a relative tooth height(h/a=0.56)are used for the first and second impellers to improve the aerodynamic performance and noise reduction effect of the fan.The total pressure and efficiency are increased by 4.52%and 2.53%,respectively.And the maximum sound power is reduced by2.54%compared to the prototype blade.However,the maximum equivalent stress of the first-stage blade is greater than that of the traditional fan.Through the strength check,it is found that the strength requirements of the material are still met,and no cracks and fractures will occur.By combining the wing angle blades and the serrated leading edge blades,the serrated leading edge wing angle blade fan is designed.The flow field,sound field and blade strength of the fan were analyzed,and it was found that the serrated leading edge wing angle blade is compared with wing angle blades and serrated leading edge blades can significantly reduce the vortex core distribution of the trailing edge shedding vortex,but the vortex strength of the shedding vortex is greater than that of the leading edge serrated blade.The efficiency and pressure of the serrated leading edge blade angle blade fan in the full flow range are increased by 3.66%and 5.73%on average,and by 2.76%and 4.62%respectively at the rated flow point.The sound pressure level has been reduced by 0.46%and 2.69%.After checking the strength of the blades,it was found that the maximum equivalent stress of the serrated leading edge bladed blade fan was 26.59%and 0.33%lower than that of the prototype blade on the first and second-level blades,and the amount of deformation was reduced by 38.18%and27.88%,respectively.