缓凝砂浆在单螺杆挤出机中的流动分析

A Visualized Flow Analysis of the Postponed-Set Mortar with Bingham Liquid in A Single-Screw Extruder

在预应力钢筋上连续包裹一层缓凝砂浆是新型缓粘结预应力混凝土体系得以工程应用的关键。为了弄清包覆过程,了解物料性能、加工条件和螺杆参数等输入变量对包覆输出结果的影响,基于缓凝预应力筋包覆试验,运用Polyflow软件,对宾汉姆体的缓凝砂浆在螺旋槽内流动和变形情况进行CFD(computational fluid dynamics)模拟。得到了可视化的速度场和剪切速率场,模拟了分析螺杆转速、螺杆几何参数对物料流变特性的影响。模拟结果可视,且直观地验证了包覆试验现象,揭示了包覆机理,为包覆装置可靠作业和结构优化提供了理论依据。

For a new type of bond-retarded prestressed reinforced concrete system, successive coating-a lay of postponed-set mortar （PSM） on prestressed strand is a key to its engineering application. In order to clarify the coating process and the influence of material characteristics, processing conditions and screw geometry parameters on the coating product, the visualized velocity and shear rate flow fields in screw channel were simulated and analyzed based on PSM coating experiments. A commercially available finite element software Polyflow was emp deformation for PSM of Bingham liquid in a screw channel with d oyed to simulate the flow and fferent screw revs and different screw geometry parameters. Simulation results verify the coating experiments and reveal coating mechanism, therefore lay a theoretical foundation for the successive coating process and structural optimization.