| Air-assisted sprayer is a mechanical equipment used for dust removal and haze removal.Through high-speed output air flow,the atomized fine water mist is sprayed out.The water mist absorbs the dust in the environment and then settles,reducing the dust particles suspended in the environment.The air-assisted sprayer is composed of an air supply system and a water mist system.The role of the air supply system is to gather the air through the axial flow fan and accelerate the output,so as to drive the water mist to spray.In this paper,the air supply system of a certain 80 S spray machine in an enterprise was taken as the key research object.By using computational fluid mechanics theory and numerical simulation method,the characteristics of internal and external flow field of axial flow fan under different structural parameters are studied and analyzed,and the optimal structure is obtained by multi-objective orthogonal optimization,so as to improve the working efficiency and the scope of action.The main research contents are as follows:(1)Influence of cone taper and guide vane structure of axial flow fan on performance of sprayer.On the basis of the original blade model,the models of different cone and guide vane were established,and the basin in the fan was simulated by numerical simulation method.The analysis results show that the taper of axial flow fan has a direct influence on the range of the fan,and the increase of the taper of the contraction cylinder decreases the air volume and the range of the spray machine.The trailing edge shape of the guide vane also affects the performance of the fan.The trailing edge lengthening guide vane and serrated guide vane can reduce the average outlet velocity and the range,but the range is small.For the guide vane with opening design,only the airflow velocity increases slightly at the opening of the blade,which has little influence on the fan range.(2)Influence of impeller structure and blade airfoil on performance of sprayer.The impeller,the core component,is taken as the key research object to improve the range and efficiency of the fan.Firstly,the original blade model is not changed,the connecting structure of the blade and the hub is simplified,and different slotting schemes of the blade tip are designed.Then change the blade airfoil to LS airfoil for further analysis.The results show that the simplified connection structure can improve the range and efficiency.The blade tip structure has little influence on the fan range,and the slotted structure from the middle tip to the periphery can slightly improve the relative efficiency of the fan.The impeller of LS airfoil can significantly improve the flow rate and range of the fan,and the corresponding shaft power will also be increased.(3)Multi-objective orthogonal optimization analysis of impeller parameters of axial flow fan.Orthogonal test was carried out for LS airfoil impeller by changing the two-stage impeller to antirotation mode.The primary and secondary factors affecting the range and efficiency of the fan were discussed by introducing the concept of relative range,and the optimal parameter combination satisfying both optimization indexes was obtained.The analysis results show that when the hub ratio is 0.38,the number of firststage impeller blades is 12,the installation angle is the design installation angle,the number of second-stage impeller blades is 7,and the installation Angle is reduced by2.5°,the range and efficiency requirements can be met. |
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