Research On Numerical Model Of Ice-water Mixture Based On DEM-LBM Coupling Algorithm

Ice-water mixtures are the most common material forms of polar ships,mainly distributed in the channel of crushed ice and the keel part of the ice ridge.In order to explore the mechanical properties of ice-water mixtures,a DEM-IMB-LBM(discrete element-immersion moving boundary-lattice Boltzmann method)coupling algorithm was developed and a numerical model of ice-water mixture was established for study.The numerical simulation mainly takes polygons as the research object,and establishes a fluid-structure interaction algorithm for its interaction with fluids,and the flow field influencing factors of the ice crushed ice gap inside the ice ridge keel are studied,in which the lattice Boltzmann method simulates the fluid,the interaction between solid particles and with the wall is solved by the discrete element method,and the complex moving boundary of polygon particles is processed by the immersion moving boundary method.In this paper,the developed DEM-IMB-LBM coupling algorithm is used to simulate the single-particle settlement of the approximately spherical positive 32 polygon,and the settlement simulation is analyzed by changing the lattice size,distance from the container wall and other influencing factors,and the previous work results are compared.At the same time,the DKT phenomenon(traction-contact-tumble)of the double positive 32-sided shape is also verified,and the accuracy of the coupling algorithm DEM module is further verified.A large number of scholars explore the problem of fluid-structure interaction,most of them take spherical elements as the mainstream,and the research literature on square elements is obviously much less,so after completing the verification of DEM-IMB-LBM coupling algorithm,the sedimentation numerical simulation of square particles is carried out,and the influence of Reynolds number,particle aspect ratio,container width and other factors on the settlement of square particles is studied,and the "inverted T-shaped" structure phenomenon of bidirectional particles and the settlement characteristics of bidirectional particles at different positions are also verified,and the procedure is further verified in combination with the previous work.Sea ice in nature has many shapes,including a large number of concave polygonal forms of crushed ice.Therefore,the previous numerical simulation of polygon settlement is expanded,and the numerical simulation of sedimentation of concave polygon particle group represented by two concave polygon forms and the numerical simulation of settlement of mixed polygon are simulated,and the simulation effect is good.Finally,a numerical model of ice-water mixture is constructed by taking the keel part below the ice ridge waterline as the research object,and the influence of loading plate speed,particle density and particle morphology is explored respectively.