【作者】 黎明；

【导师】 张政；

【作者基本信息】 北京化工大学 ， 化学工程， 2001， 硕士

【摘要】 密相栓流气力输送在工业界有着的广泛的应用，但气固两相的流动及其相互作用十分复杂，人们对其中的规律认识还不清楚；另外，对密相栓流气力输送的数值模拟研究很少见，因此对该过程进行数值模拟研究和实验研究具有重要的工程应用价值和理论意义。 本文在密相气固两相流动模型中，流体相采用欧拉坐标下的连续体N-S方程，颗粒相的运动在拉格朗日坐标系下采用确定性轨道模型，流体与颗粒之间考虑双向耦合，并引入研究分析不连续岩体的非连续介质力学方法—离散单元法(DEM Distinct Element Method)来模拟多个颗粒之间长时间的相互作用。为验证模型和程序的正确性，先后对颗粒的降落过程、射流流化床和普通流化床进行了数值模拟，结果令人满意。 本文首次采用基于离散单元法的欧拉-拉格朗日模型对水平管中多个栓的脉冲气刀式栓流气力输送过程进行模拟，结果再现了栓的滑落、形成和运动过程，与经典的成栓模式和实验观察到的现象基本一致，本文同时考察了不同入口速度和不同初始栓长对密相栓流气力输送过程的影响。 本文的研究结果表明，离散单元法在密相气固相流的数值模拟研究中具有广阔的前景。更多还原

【Abstract】 Dense phase pneumatic conveying of slug flow is widely applied in industry. Because of its complication, the detailed information of fluid flow has not been well understood. Besides, the numerical simulation on the process is seldom found in the literates, so it is worth to be studied from both theoretical aspect and engineering application aspect.In this dissertation, a dense phase gas-solid two-phase flow model is developed, which includes two parts: fluid model and solid particle model. In the model fluid field is obtained by solving N-S equation under Euler coordinate system, while solid particle movement is simulated by trajactory model under Lagrange coordinate system, where two-way coupling effect between gas and solid phase is considered. Distinct Element Method(DEM),a powerful tool in the mechanical analysis of discontinuous medium, is introduced to simulate the contact force between parti lcles. In order to test the accuracy of the model and the correctness of the programme, the free falling movement of particles and fluidized bed performance is calculated. The results are satisfactory.It is the first time that distinct element method attached in a Eulerian-Lagrangian model is used to numerically simulate pneumatic conveying of multi-slug flow in a horizontal pipe. The movement of the slug is reproduced in the simulation, which repeats the performance shown in experiment as a whole. Furthermore, effects of the innet velocity and initial length of slug are studied.The result indicates that DEM has wide prospects in numerical simulation of the dense solid-gas flow.更多还原