固废流化床非球颗粒流动特性的CFD-DEM模拟研究

The flow characteristic of the gas-solid two phases flowing in the solid waste fluidized bed is the key problem of controlling the chemical reaction and pollution in the bed. The co-fluidization has its own characteristics for the breakage/no-breakage non-spherical mixed particle compares to the conventional coal-fired fluidized bed. It is the frontier and hot research question in the international. On the basis of previous studies, this project extended the non-spherical particle model to arbitrary shape, especially the mixed particle of different size, different weight and different shape due to breakage. The breakage model was founded in the project. And the algorithm of particle breakage was investigated. The drag force was measurement accurate according to the experiment. The gas-solid coupling algorithm was founded, especially the tracking problem of the different non-spherical particles in the mixing system. Finally, the co-fluidization characteristic of non-spherical and bed materials in the fluidized bed will be investigated by establishing the CFD-DEM two way coupling method of spherical and non-spherical particle. This project will elevate the DEM simulation of non-spherical particle to a higher level.

固废流化床内的气固流动特性是床内化学反应和控制污染的关键。固废流化床内各种破碎/未破碎的非球形固废颗粒与床料共流化，与常规球形颗粒的燃煤流化床相比具有自身的特点和复杂性，是当前国际上的前沿和难点研究问题。本申请项目在前期研究的基础上，将非球形颗粒的DEM数值模拟扩展到其它任意非球形颗粒，尤其是破碎及未破碎的不同大小、不同重量、不同形状混合非球形颗粒的模拟研究。本项目深入探讨了非球形颗粒的破碎机理，建立非球形颗粒的破碎模型；研究破碎后的非球形颗粒的受力和运动数理模型；建立破碎/未破碎非球形混合颗粒体系气固双向耦合的CFD-DEM数值试验研究；揭示介尺度上的破碎/未破碎非球形颗粒混合体系在反应器中的运动机理。其研究成果有望将非球颗粒的模型和模拟方法完善和上升到一个更高的水平.

随着经济的快速发展，环境污染问题也越来越严重，如大气污染、固体废弃物等方面的问题都亟待解决。颗粒流动是国内外学者研究的热点问题，在处理大气污染及固体废弃物的很多方法中，颗粒流动均能起到决定性作用。本项目在这个背景下，深入探讨了反应器中颗粒的形状对流动机理的影响。构建了单一非球形颗粒的破碎机理，建立了异重/异形/异径混合非球形颗粒的碰撞、受力数理模型及其气固双向耦合CFD-DEM模型，发展了新的浓度测量方法，研究了混合非球形颗粒在反应器内的运动机理及扩散行为。