压力筛内部纸浆悬浮液流场的数值模拟

Numerical simulation of pulp suspension flow field inside pressure screen based on FLUENT

为了克服废纸浆压力筛筛浆过程中孔、缝堵塞问题,在分析测试废纸浆在不同浓度下黏度的等流体特性的基础上,通过Unigraphics NX(UG)软件对压力筛内部流场建立模型,运用计算流体动力学软件(ICEM CFD)和FLUENT软件对压力筛内部纸浆悬浮液流场进行数值模拟,得到了压力筛内部筛浆区流场的压力、湍流强度和流速的分布。结果表明:对于常用典型代表性的浆料和结构特征以及运行参数的压力筛,波纹筛板湍流强度最高为306%,而筛孔内湍流强度最高为128%;筛孔进口处最大流速为8.16 m/s,出口处最大流速为3.5 m/s,平均流速约为1.2 m/s;筛框处旋翼头部静压力最大约为1.8×105Pa,旋翼尾部静压力最小约为6.92×104Pa。

In order to avoid blocking of holes and gaps of the pressure screen in the process of screening waste paper pulp screening,the fluid characteristics such as viscosity of the waste paper pulp with different concentrations were first tested and analyzed;and then the flow field inside pressure screen was drawn with Unigraphics NX software（UG） finally,pulp suspension flow field inside the pressure screen was simulated with computational fluid dynamics（ICEM CFD） and FLUENT software.From the numerical simulation,the detail distribution of the pressure,turbulence intensity and velocity of pulp flow in the screening zone were obtained.The results for the pressure screen used with representative pulp and structure＇s characteristics and running parameters showed that the highest turbulence intensity near the corrugated plate was 306 % and highest turbulence intensity in the screen holes was 128 %;the maximum velocity at the screening holes＇ inlet was 8.16 m/s,the maximum velocity at the screening holes＇ outlet was 3.5 m/s,and the average was 1.2 m/s;and the biggest static pressure near the screen plate at the head of rotor wing was about 1.8×105 Pa and the minimum static pressure at the end of rotor wing was 6.92×104 Pa.