Design,Optimization And Experimental Study Of Multifunctional Liquid Waste Disposal Vehicle

With the acceleration of the urbanization and the increase of population density in China,not only the load of sewage pipelines increases by years but also the blocking often occurs,so it is extremely necessary to design suction sewage trucks to hand the blocking problem.For the traditional suction sewage trucks,the sewage is first suctioned and then transported to the storage place without any treatment,resulting into the unwillingness of the sewage plant and the landfill site to receive.Thus,quite often,liquid waste with high pollution is then slinkingly discharged into the municipal pipeline or other remote places,thereby undoubtedly causing serious environmental problems.Therefore,it is significantly important to develop novel methods to tackle the difficulties of the liquid waste discharge.In view of the problem of liquid waste treatment in sewage pipeline,this work attempts to design a novel liquid waste disposal vehicle(LWDV)with the capacity of on-site treatment of sewage based on the concept of "on-site treatment".This design idea can promote the alteration of the traditional way that only suction and transfer are involved.Due to the high-performance requirements of the proposed novel LWDV in practical application,the lightweight design and reliability analysis are first conducted;The rotation mode and rotation speed of the screen cylinder screw device,belonging to the first stage solid-liquid separation system of LWDV,are then deduced by using the fluid-solid coupling theory;The suspension of LWDV is later optimized by simultaneously considering the vehicle properties and the eccentric vibration of the rotating parts;A prototype is finally developed,followed by typical tests under various operation conditions.The main work contains:A multi-functional vehicle is designed to treat liquid waste on site,and a solid-liquid separation system with double rotors is proposed.According to the requirements of working conditions,a new type of liquid waste treatment vehicle with the function of on-site separation and treatment of sewage and sewage is designed.In addition to the function of traditional sewage suction vehicle,it is also equipped with two-stage solid-liquid separation system and other related functional devices.The designed system can roughly conduct the solid-liquid separation for the suctioned multi-phase liquid,and dehydrate the separated solid matter as much as possible to facilitate its transport.According to the characteristics of high-proportion of solid matter in the liquid waste treatment of sewage pipeline,the rotation speeds of the spiral axis of the first stage solid-liquid separation system and the screen cylinder are designed to be different,which guarantees the separation effect and avoids the blocking of the screen cylinder at the same time.Moreover,the numerical simulation method is used to analyze the effect of the separation and the transport of the sewage under different groups of rotation speeds of the spiral shaft and the screen cylinder of the first stage solid-liquid separation system.Through the comparison of the transportation speed of the sewage under different groups of ration speeds of the spiral shaft and the screen cylinder of the first stage solid-liquid separation system,the best rotation speed of the screen cylinder spiral shaft differential rotor system is obtained,which is also verified by experiments.A sensitivity hierarchical filtering method is developed to solve the problem that small load transfer path disappears due to ill conditioned load in the process of topology optimization.In terms of the problem of load sickness existing in the service condition of the typical parts belonging to the first stage solid-liquid separation system of the LWDV,the strategy of sensitivity hierarchical filtering is proposed to perform the topology optimization,effectively avoiding the phenomenon that the transmission path of the weak load is disappeared in the traditional topology optimization method.The strategy of sensitivity hierarchy filtering is performed according to the magnitude of the loading amplitude as well as the strain energy value of the structure.Through two coefficients,respectively for comparison and amplifying the influence of strain energy,the sensitivity values are stratified.Then,the sensitivities at different stratifications are filtered by different strategies so as to obtain the optimum material layout under multi-load.Several numerical examples are tested to verify the effectiveness of the strategy of sensitivity hierarchical filtering.Finally,this strategy is adopted to conduct topological design for the typical parts of the LWDV.A reliability analysis method based on Pan grey number for mixed structure with multi-source uncertainties is developed to solve the problem of inter zone expansion.Aiming at the problem of high failure rate and inconvenient maintenance of the solid-liquid separation system of the LWDV due to poor working conditions,a reliability analysis method of the multi-source uncertain hybrid structure is developed based on the algorithm of universal grey numbers.In this method,the fuzzy parameters are transformed into the equivalent random parameters by the isentropic principle,and the equivalent random parameters and the original random parameters are transformed into interval variables by the 3? criterion.On this basis,the mixed reliability problem is transformed into the reliability problem with only interval variables,namely the non random reliability analysis problem.For the problem of interval expansion existing in the interval algorithm,the universal grey mathematics method is used to conduct the non random reliability analysis,resulting into more conservative reliability calculation results.Lastly,this presented method is successfully extended to solve the issue of the typical parts of the LWDV.The dynamic model of the whole vehicle,including the loading eccentric working system,is first established.Then,the dynamic analysis of the LWDV is conducted under various operation conditions.The suspension parameters of the vehicle are optimized through the multi-objective genetic algorithm to achieve the good road adaptability of the suspension system.Additionally,the optimized suspension system effectively improves the acceleration of the vehicle body on sinusoidal road and random road,and improves the driving comfort of the vehicle.After the optimization,the dynamic deflection of the suspension system is reduced;moreover,the dynamic load of the wheel and the driving safety of the vehicle are also clearly improved.The test bench of primary solid-liquid separation system and the sample LWDV are made,and the performance parameters are tested and verified.By making a test bench for the primary solid-liquid separation system,the material transmission speed and treatment efficiency of the primary solid-liquid separation system are tested.According to the treatment objects and working conditions of the multi-functional liquid treatment vehicle,the overall treatment efficiency of the vehicle,the degree of sewage purification and the moisture content of solid waste after dehydration are tested.According to the requirements of various working conditions,two new LWDVs with the function of on-site sewage separation and treatment are designed.In addition to those functions of traditional sewage suction vehicle,the vehicle is equipped with two-stage solid-liquid separation system and other related functional devices.Also,the sample vehicle is manufactured by us.Some tests relevant to the treatment efficiency,sewage purification degree and moisture content of dehydrated solid waste are made.The experimental results show that the efficiency of the whole process of the equipment is significantly improved,compared with the traditional sewage suction truck.After the treatment,the main pollutants in the water quality meet the level C standard of the national standard "water quality standard of sewage discharged into urban sewer",which can be directly discharged to the underground sewage pipeline.The moisture content of solid waste produced by the first stage solid-liquid separation system meets the requirements of the national standard "pollution control standard for domestic waste landfill".The solid waste produced by the second state solid-liquid separation system can be used as organic fertilizer raw material.