Numerical Simulation Study On Flow Field And Mechanical Characteristics Of Suspend Slab Of The Sand Funnel Based On Fluid-Solid Coupling Method

Sand funnel is currently one of the most mature and efficient secondary sediment treatment facilities for sediment treatment.Suspended slab is an important part when the sand funnel is running.The design of the suspended slab and its mechanical stability in operation directly affect the actual operation effect of the sand funnel.At present,the researches on the sand funnel regard the suspended slab as a rigid body,but only study the single physics field of the sand funnel,that is,the flow field characteristics,and do not analyze the flow field and the structure.In order to further investigate the mechanical cause of the failure of the suspended slab,this paper uses a fluid-solid coupling algorithm to carry out a three-dimensional numerical simulation of the sand funnel.The main research contents and conclusions are as follows:(1)By using the fluid-solid coupling algorithm to carry out three-dimensional numerical simulation of the sand funnel,the data of the distribution of the flow field inside the sand funnel and the equivalent stress and deformation of the suspended slab under typical conditions were obtained.(2)Based on the fluid-solid coupling algorithm,coupled with large eddy simulation and VOF method,the numerical simulation of the flow field inside the sand funnel is found.The flow field distribution calculated by the numerical simulation is in good agreement with the results of previous PIV tests,and the stable existence of a three-dimensional air funnel near the center of the funnel chamber indicates that the calculation results obtained by the three-dimensional numerical simulation of the sand funnel using a fluid-solid coupling algorithm are reliable.(3)Under the same working conditions,the minimum error of equivalent stress and deformation of the suspended slab calculated by unidirectional and bidirectional fluid-structure coupling algorithms is only 2.7%.It is shown that the numerical simulation can be performed by using the unidirectional fluid-structure interaction algorithm under the premise of ensuring certain accuracy.(4)After numerical simulation of steel suspended slab with different properties,it was found that after the thickness of the suspended slab was increased from 1 mm to 2 mm,the maximum equivalent stress could be reduced by 33.7%under the same working conditions.And through spectrum analysis,it is found that the areas where the suspended slab is most susceptible to fatigue damage caused by dynamic and static interference are the two ends of the suspended slab.