基于DEM的埋管鼓泡流化床内颗粒运动特性模拟

该文采用离散单元法(DEM)对水平埋管的鼓泡流化床内颗粒流化过程进行了数值模拟研究。DEM方法通过求解Newton方程来模拟颗粒的运动过程,气相仍采用连续流方法模拟。因此,DEM方法能够获得颗粒尺度量级的详细结果。通过模拟不同埋管布置方式下流化床内密相区颗粒流化过程,研究了埋管布置方式对于鼓泡流化床内的颗粒运动的影响。结果表明:埋管布置方式会改变床层有效流通面积和埋管对颗粒的阻碍作用等,从而影响流化床内的颗粒群和气泡形态。埋管数量越多,颗粒与埋管由于相互作用而消耗的能量越大,平均颗粒速度和颗粒温度值越低。不同的埋管布置方式会导致颗粒混合速率的差异,增加埋管数量会降低颗粒混合程度。

DEM simulation of the behavior of particles in a spout-fluid bed with immersed tubes

The discrete element method(DEM) was used to study the behavior of particles in a spout-fluid bed with horizontal immersed tubes.In the DEM simulations,the particles were individually traced by solving Newton’s equations of motion,while the fluid phase was treated as a continuum.Therefore,the DEM simulation provides particle level information.The effect of tube arrangement on the particle and bubble behavior in the packed bed region was investigated by varying the tube arrangement.The simulations show that the tube arrangement greatly influences the kinetic behavior of the particles.The effective flow area and interaction forces between the immersed tubes and particles varied with different tube arrangements.More immersed tubes gave lower averaged particle velocities and temperatures.The particle mixing rate also differed for different immersed tube arrangements.The particle mixing was reduced by more immersed tubes.