正向除渣器中纤维流动性与收集效率的模拟分析

为了更好地评估和优化正向除渣器的结构性能,了解纤维在其内部纸浆悬浮液流场中的运动特征和收集效率。基于纤维的吸水膨胀性,结合球形纤维粒子的概念,笔者利用FLUENT软件对正向除渣器内部纸浆悬浮液流场进行了数值模拟。结果表明:模拟实验所取的两种纤维中,从正向除渣器良浆出口流出的湿纤维a的颗粒轨迹数要高于湿纤维b的颗粒轨迹数,同时计算得到湿纤维a和湿纤维b的收集效率分别约为58%和55%; 纤维的收集效率随着纤维颗粒的密度、直径和长度的增大而降低,其中纤维收集效率对纤维长度的敏感度较小,当纤维长度从1 mm增大到5 mm时,两种湿纤维收集效率的最大差值约为6%; 而纤维收集效率对纤维直径的敏感度相对较大,当纤维的直径在10～70 μm之间时,两种湿纤维的收集效率最大差值约为40%。

Simulation analysis of flow characteristics and collection efficiencies of fibers in forward cleaner

In order to analyze the flow characteristics and collection efficiency of fiber in the internal pulp suspension field of forward cleaner,the internal pulp suspension field was numerically simulated with FLUENT software according to the swelling performance of fiber between dry and wet fiber, and combined with the concept of spherical fiber particle. The results showed that the particles track number of wet fiber a was higher than that of wet fiber b, while the two kinds of fibers from the accept outlet of forward cleaner, and according to the calculation that the collection efficiencies of fiber a and fiber b were 58% and 55%, respectively. The collection efficiency of fiber gradually decrease along with the increas of density, diameter, length of fiber, and the collection efficiency of fiber was not sensitive to the length of fiber. When the fiber length increased from 1 to 5 mm, the biggest drop value of collection efficiency of fiber was about 6%. The collection efficiency of fiber was sensitive to the density of fiber, and the biggest drop value of collection efficiencies on the two kinds of fibers was about 40% when fiber diameter changes from 10 μm to 70 μm.