基于数值模拟的新拌混凝土竖直泵送流动行为
作者:
作者单位:

1.东南大学 材料科学与工程学院,江苏 南京 211189;2.重庆大学 材料科学与工程学院,重庆 400044

作者简介:

徐支松(1991—),男,安徽马鞍山人,东南大学助理研究员,博士. E-mail: xuzs@seu.edu.cn

通讯作者:

刘加平(1967—),男,江苏南通人,东南大学教授,博士生导师,博士. E-mail: liujiaping@cnjsjk.cn

中图分类号:

TU528.53

基金项目:

“十四五”国家重点研发计划项目(2021YFF0500800);国家自然科学基金资助项目(52208231);江苏省卓越博士后计划(2022ZB76)


Numerical Simulation on Vertical Pumping Flow Behavior of Fresh Concrete
Author:
Affiliation:

1.School of Materials Science and Engineering, Southeast University, Nanjing 211189, China;2.College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China

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    摘要:

    借助数值模拟研究了3种流动性的混凝土在竖直向上泵送时的管内流动行为,分析了混凝土内部压力和流速的分布规律.结果表明:泵送压力主要受润滑层性质的影响,其纵向分布与管壁阻力沿程变化规律有关,截面中心的泵送压力略高于管壁处;混凝土在管内的流动存在“前进—扩散—滞留堆积—汇聚”的行为特征,并据此分析了润滑层的形成和粗骨料的迁移,解释了泵送离析和堵管的原因.

    Abstract:

    To examine the pumping flow behavior of fresh concrete in vertical upward pumping, the flow of three concretes with different fluidities in a vertical pipeline was investigated by numerical simulation. The distribution of pressure and velocity field in concrete during pumping were analyzed in detail. The results show that the magnitude of pumping pressure is mainly affected by the properties of the lubrication layer. The longitudinal pressure distribution is related to the pattern of boundary resistance variations along the pipe wall, while the pressure at cross-section center is marginally higher than that at the pipe wall. Moreover, the research identified the flow behavior of concrete in the pipe, involving progression, diffusion, retention, accumulation, and convergence. Based on this, an analysis was conducted to understand the formation of the lubrication layer and the migration of coarse aggregates. These findings explained the reasons for concrete pumping segregation and plugging.

    表 1 混凝土配合比Table 1 Mix proportions of concretes[15]
    图1 混凝土泵送流量与泵送压力损失的关系Fig.1 Relationship between concrete pumping flow rate and pressure loss
    图2 混凝土管内流动模型Fig.2 Concrete pipe flow model
    图3 泵送压力的理论结果和模拟结果Fig.3 Theory and simulation results of pumping pressure
    图4 泵送混凝土内中轴线上的压力分布Fig.4 Pressure profile along central axis in pumped concrete
    图5 泵送混凝土内水平截面上的压力分布Fig.5 Pressure profile on horizontal sections in pumped concrete
    图6 竖直泵送混凝土在管内的速度云图Fig.6 Velocity contours of vertical pumped concrete in pipe
    图7 竖直泵送混凝土纵向速度分布Fig.7 Velocity profile along flow direction in vertical pumped concrete
    图8 竖直泵送混凝土径向流速分布Fig.8 Velocity profile along radius direction in vertical pumped concrete
    图9 泵送混凝土在管内的相对流动行为Fig.9 Relative flow behavior of pumped concrete in pipe
    图10 泵送前端混凝土内粗骨料体积分数的变化Fig.10 Volume fraction variation of coarse aggregate in front of pumped concrete
    表 2 试验材料的流变参数Table 2 Rheological parameters of fresh materials
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引用本文

徐支松,袁世军,刘加平.基于数值模拟的新拌混凝土竖直泵送流动行为[J].建筑材料学报,2024,27(6):551-558

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  • 收稿日期:2023-12-26
  • 最后修改日期:2024-01-14
  • 在线发布日期: 2024-07-11
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