Study On Effect Of Blade Parameters On Performance And Internal Flow Of Small Axial Flow Fan With Splitter Blades

Currently, the small axial flow fan is the main equipment of ventilation and heat dissipationin the electronic components, whose performance will directly influence the effect of electronicequipment. At the same time, with the improvement of people’s life quality, the small axial flowfan as the main noise source in the work environment, its acoustic performance is attracted moreattention. So how to design the small axial flow fan with better effect of heat dissipation andlower noise is currently the key program and heat topic in the research.In this thesis, the small axial flow fan with five blades is selected as the research prototype,the small axial flow fans with splitter blades are designed, the effect of different chord lengthsand the circumferential positions of splitter blade on performance of small axial flow fans withsplitter blades is studied with the help of the numerical simulation methods, then the staticcharacteristics, internal flow and aeroacoustics of small axial flow fan are analyzed; The schemeof orthogonal experiment optimization is developed, and the optimization objective is staticpressure and noise, then the optimal small axial flow fan with splitter blades is designed,experiment is carried out to test the static characteristic of the optimal fan and prototype fan. Themain contents and achievements of the thesis are as follows:(1) The small axial flow fan with five blades is selected as the main research object, thesmall axial flow fans with splitter blades are designed by adopting the method of geometricdesign. The numerical simulation process in this thesis is briefly described.(2) Six models with different chord lengths of splitter blade are designed, and the staticcharacteristics, pressure distributions, velocity distributions and aerodynamic noise of thesemodels are analyzed by numerical simulation. The research results show: The appropriate chordlength of splitter blade is good for the improvement of performance of small axial flow fan withsplitter blades, and the chord length of splitter blade which is too long or too short is unfavorableto improve the performance.2/6chord length,3/6chord length,4/6chord length are the bestchoices.(3) The internal flow field and noise of five models with different circumferential positionsof splitter blade are numerically simulated, and the static characteristics, internal flow and thecharacteristic of aerodynamic noise are analyzed. The results show that the overall performancesof the model of middle position, the model of lean12°to pressure side and the model of lean12°to suction side are the best, the circumferential positions of splitter blade locate in the middle or lean the appropriate degrees to both sides are good for the improvement ofperformance of small axial flow fan with splitter blades, and the splitter blade is too lean to oneside is unfavorable to improve the overall performance.(4) The chord lengths, the circumferential positions and installation angles of splitter bladeare selected as optimization variables, the optimization objectives are static pressure and noise.The scheme of orthogonal experiment optimization is developed, multi-objective optimizationfunction is established, entropy weight method is applied to determine weights of optimizationobjective, and the range analyses method is adopted to process the data, the optimal small axialflow fan with splitter blades is designed, experiment is carried out to test the static characteristicof the optimal fan and prototype fan. The results of the study show: The installation angle is themost important parameter to improve the performance of small axial flow fan with splitter blades,and then circumferential position and chord length respectively. The numerical simulation resultsshow that the static characteristic of the optimal model is significantly better than that of theprototype, the internal flow conditions is improved, the aerodynamic noise have the reduction ofabout6dB. The static characteristics of the experimental results show that the performance of theoptimal fan is better than the prototype fan, the trend of numerical simulation results andexperimental measurement results is consistent, and the reliability of the numerical simulation isverified.