Optimization Design Of Aeration Blower Drived By High Speed Motor

With the intensification of the international energy situation,the concept of green,civilized and sustainable development has attracted broad attention of all circles.In the sewage treatment industry,the power consumption of blast aeration system is huge,accounting for about 30%~50% of the total power consumption.As the core of the system,the aeration blower has a broad prospect in the water treatment industry.The amount of electricity saved by improving the performance of the fan will be considerable,which is of great significance for energy saving and consumption reduction.In this paper,a centrifugal aeration blower is taken as the research object and akes high efficiency and energy saving as the starting point.The aerodynamic design and optimization analysis of each part of the fan are carried out by applying the full ternary flow simulation calculation method and using the specialized software Concepts NREC and NUMECA of turbine machinery.Firstly,the optimal design of the aeration blower starts from the impeller,which is the only work component.The purpose of optimizing the impeller is to change the size of tip clearance and the length of splitter blade.The tip clearance size is adjusted within the range of 0.2-0.6mm.The results calculated by FINE/Turbo show that the leakage loss increases with increasing tip clearance.Taking pneumatic performance and shape variables into consideration,the clearance size of 0.3mm was selected as the final design scheme.For the splitter blade,the axial position of its leading edge line is controlled to change the blade length.QO lines are uniformly distributed in the meridional flow passage of the impeller,so that the leading edge of the splitter blade changes within the range of the 5th to 10 th QO lines.By comparing the results of aerodynamic calculation,it is found that the leading edge of the small blade at the 8th QO line has the best performance.Furthermore,the splitter blade can effectively reduce the blade loading.After the optimization of tip clearance and splitter blade,the isentropic efficiency of impeller is 90.56%.Next,according to geometric and aerodynamic parameters,the stator component-blade diffuser is designed.A parabolic mean line and the thickness distribution of NACA65 airfoil are used to design the diffuser.The 3D modeling was performed by CREO and the numerical analysis was carried out in grade ii environment with FINE/Turbo.Due to the existence of severe separation vortices at the blade back of the initial diffuser model,it is necessary to be optimized it.By changing the blade bending Angle on the basis of the initial model,the swirling flow was eliminated,and the stage efficiency was increased by 2%.Under the premise of constant cascade consistency,increasing the bending angle can extend the working length of the blade passage,which is an effective means to improve the performance.In addition,the effect of blade thickness on stage performance is discussed.The diffuser with different blade thickness can be obtained by changing ?c.It can be found that when the value is 0.07,the stage performance of the diffuser is better than other diffuser.The isentropic efficiency is 87.67% and the total pressure ratio is 1.848.Finally,an asymmetric circular volute model is established,which is mismatched with impeller and diffuser.CFD calculation result shows that the fan efficiency is 84.42% and the total pressure ratio is 1.807,which is higher than the required value of 1.78.From this point of view,the design of aeration blower drived by high speed motor can meet the requirements.Throughout the aerodynamic design process of centrifugal aeration fan,the impeller,diffuser and volute are optimized and get a reasonable design scheme.It has reference and guiding significance for the pneumatic design of compressor in the future.