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针对 15°二维锥形填充床 ,在不同表观气速下 ,用热线风速仪测定了床层表面的气速分布 ,用U形管压差计测定了床层压降 .测量结果表明 ,在较高的表观气速下 ,床层表面的气速分布非常不均匀 ,床层结构出现局部变形 ,Ergun形式的计算方程不能正确预测床层压降 .通过使用数字照相机对床层局部流化过程进行了观测 ,发现由于床层流通面积的变化和收缩形壁面对近壁区气体流动方向的诱导作用 ,造成气速分布的高度不均匀性 ,在较高的表观气速下床层结构出现局部变形 ,并最终导致局部流化现象的出现
According to the 15 ° two-dimensional conical packed bed, the distribution of gas velocity on the surface of the bed was measured with a hot wire anemometer at different superficial gas velocities, and the pressure drop of the bed was measured by U- At higher superficial gas velocities, the gas velocity distribution on the surface of the bed is very non-uniform and the bed structure is locally deformed. Ergun-type calculation equation can not predict the bed pressure drop correctly. By using a digital camera, It is observed that the distribution of bed flow area and the shrinkage wall shape induced the gas flow in the near wall region, which resulted in the highly inhomogeneous distribution of gas velocity. Under the condition of high superficial gas velocity, Local deformation occurs in the structure and eventually leads to the appearance of localized fluidization