| With the increase of national environmental protection,road sanitation is developing rapidly towards mechanization and automation.As an important branch of road cleaning vehicles,the washing and cleaning car occupies most of the domestic cleaning industry market by virtue of its own excellent cleaning and dust removal performance.Due to the late start of the research on the domestic washing and cleaning car,many enterprises mainly carry out secondary design with the structure of the foreign washing and cleaning car as the reference,and less independent research and development,resulting in the lack of systematic guidance for the design and optimization of the washing and cleaning car.In this paper,the pneumatic system,the core working system of a certain 8-ton washing and cleaning car,is studied.The following works are carried out:（1）Analyze the working principle of pneumatic system of washing and cleaning car,describe the physical properties of working medium and dust particles in pneumatic system,reveal the motion mechanism of dust particles in gas-phase media and gas-liquid two-phase media from the angle of fluid mechanics,the results show that the drag force generated by a liquid phase is to a certain extent,promote the starting of dust particles,and the liquid viscosity can change the pipeline between the motion state of the dust particles,but it does not change the minimum suspension speed required to transport dust particles.（2）By using FLUENT,four groups of key structural factors such as longitudinal width L,height H,Angle θ between front rubber and ground,and gap A between front rubber and side of the suction cup are simulated and analyzed by parametric design method.The results show that the suction cup has the best performance when L=220mm,H=93mm,θ=70°,a=7m.The optimum installation Angle of conveying pipe is analyzed and the calculating formula of conveying pipe installation length is deduced,and through parametric simulation analysis,the optimal diameter of conveying pipe is 170 mm.A multifunctional box is designed which can store water and sewage simultaneously.（3）The sucker structure was optimized to reduce the Angle α and β between the sucker outlet and the ground,and a bell mouth device was installed between the conveying pipe and the sucker,so that the conveying capacity of dust particles in the sucker center was significantly improved,the internal resistance was reduced by 20%,and the residence time of dust particles was reduced by 25%;The structure of the dust storage tank is optimized,the width of the bottom of the box is reduced,the shape of the inlet and outlet of the box is changed,so that the smoothness of the internal flow passage is improved,the internal resistance is smaller,and the sewage storage capacity is effectively improved,and the secondary pollution is avoided.（4）According to the optimized pneumatic system,the prototype model was made,and the overall resistance change curve and flow path resistance distribution curve of the prototype pneumatic system was measured.The error between the experimental results and the simulation data is less than 5%,which verified the effectiveness of the simulation model and laid a foundation for the subsequent system matching optimization research.（5）Based on the performance parameters of all kinds of fans,an efficient-first fan matching scheme is designed according to the similarity law of fans.The fans matched by this scheme can not only meet the operation requirements of the pneumatic system,but also ensure the highest fan efficiency,thus reducing the energy consumption of the system. |
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