Experimental Study And Numerical Simulation On Characteristics Of Municipal Solid Waste Shredder

Before the reutilization of the Municiple Solid Waste(MSW),the prepositive disposal should have be done.During the process of designing,manufacturing and utilizing the MSW with the shredder,the major considerations are the broken effect,dust issue and vibration issue.In this paper,a new type of double shaft variable speed shredder for MSW is designed,while its fragmentation,dust suppression and vibration characteristics were analyzed and optimized by the experiments and numerical simulation.Taking the blade rotation rate as the research object,the single factor experiment's results show that the blade rotation rate has a certain influence on the particle size of the crushed particles.After that,the three factors three(blade pitch,wheelbase,speed)levels orthogonal experiment is utilized to further study,which results show that the lower rotation rate has a negative effect on crushing MSW.However,along with the increasing rotating rate,the proportion of the smaller particles in the crushed product is going to reduce after growing to the top.The flow field in the designed MSW shredder is simulated and analyzed in order to study the dust issue,based on the computational fluid dynamics.Through the analysis of the internal flow field contours on the different working conditions,it can be concluded that the increasing axial distance of the two cutter shafts and the decreasing blade rotation rate both can reduce the flying dust phenomenon,respectively.Based on the before-mentioned study,the optimized asymmetric-axis crushing is designed,and modeling and simulation are built to verified the theory.It turns out that the asymmetric-axis design can obtain a higher blade rotation rate under the condition of reducing the effect of dust issue.Meanwhile,the MSW can be concentrated at the middle of the outlet area.Based on the finite element analysis theory,the mode is built to study the vibration characteristics of the shredder.The natural frequencies and mode shapes of the first six orders are calculated,which shows the outlet baffle is the weakest structure area.This area holds 2 resonant frequency points during the optimized speed range,which indicates that there are 2 rotation rate should be avoided in the optimal speed range of the motor and the blade.