Design And Analysis Of Vacuum Suction System For New Multi-function Dredging Vehicle

In recent years,dredging vehicle and other sanitation machinery in our country have achieved rapid development,in addition to the introduction of foreign advanced technology,domestic related enterprises also have independently developed a series of single functional suction sewage truck and multi-function dredge vehicle,those equipments have played a great role on construction of city.Nevertheless,the research and development of relevant equipments have only solved the problems in China from scratch,and the products have the problems of single function,high cost and low working efficiency.For vacuum sewage system in terms of dredging vehicle,as a result of the calculation in the design of the system and the selection of related equipment tend to rely on engineers' past experience to design and manufacture,the lack of relevant theoretical guidance,often lead to irrational equipment type selection,system problems such as low work efficiency,small scope of work.Vacuum suction system as the core part of the dredging vehicle,the good efficiency of the suction sewage is directly related to a high working efficiency for dredge vehicle,and the accurate calculation of system design parameters and related parts and components of good selection decision system are the premise of high work efficiency.This study is based on the new multi-function dredging project jointly developed by XMUT?VDS and Fujian Qunfeng machinery co.LTD.According to the above problems,analysis the working principle of vacuum suction sewage system and structure,according to its special working environment and technical requirements,choose effective sewage transmission technology scheme and suitable vacuum system,including vacuum pump selection and structure design and calculation of key parts.Vacuum suction system is a combination of vacuum pump,vacuum tank and suction pipe,etc.The influences of system-related design parameters on its work efficiency are the key basis for the selection and design of the above equipment and structure.In this paper,the suction process is studied and analyzed of the system.Firstly,the suction sewage mathematic model of the system is constructed and MATLAB C/C++ language are used to program the solution process of the system.Secondly,the correctness of the model is verified by the experiment of the dredging of a certain model.Finally,based on the mathematical model above,vacuum pump,suction depth,pipe material,pipe diameter and the air content in the sewage five main design parameters are detailed studied by solving program on the system efficiency of suction sewage.Among them,the study shows that the increase of air content in sewage has a significant improvement in the efficiency of the system and the pumping depth.To this end,a kind of gas-liquid mixing transportation technology is proposed to fill the air in the sewage to improve the efficiency of the system and the depth of suction.On the gas-liquid mixing transmission technology,based on the 100 mm diameter within the channel of gas-liquid two phase 2D numerical simulation,the rate of gas flow channel section,mixed flow velocity,pressure drop fluctuation of three indicators,to study the characteristics of flow pattern under the different air and water flow law,and draw up the air apparent velocity 0 ~ 40 m/s,liquid superficial velocity 3 ~ 10 m/s within the scope of the flow pattern figure.Through the flow pattern figure can be intuitive show the flow pattern transition boundary and regional distribution,and judging the pipe pressure drop fluctuations and air distribution,so as to provide reference for the choice of air flow velocity.The research shows that the vacuum suction mathematical model can provide a reliable basis for the design and selection of the system design parameters.By studying the change law of gas-liquid two-phase flow pattern in large pipe diameter channel under vacuum negative pressure condition,the gas and liquid mixed transmission technology has a significant effect on the efficiency of the dredging and the suction depth,the technical scheme is reliable and practical.