考虑空间位形力作用的微米软颗粒溶液微圆管流动规律

Micro circular pipe flow in micron-sized soft particle solution considering the effect of spatial configuration force

针对微米级软颗粒溶液在微小孔道流动不符合泊肃叶流动规律问题,考虑受固体管壁影响软颗粒形变产生的空间位形力作用,基于Navier-Stokes理论,推导软颗粒溶液在圆管中的流速分布及流量表达式,引入颗粒形变因子以表征空间位形力作用的影响;建立考虑空间位形力作用的圆管流动数学模型.由微尺度流动特征实验,得到软颗粒溶液微圆管流动规律,与泊肃叶流动对比,结果显示当管径小于颗粒直径时,相同压力梯度下考虑空间位形力作用的流速比泊肃叶流动拟合结果更接近于实验数据.通过数值计算分析发现,与泊肃叶流动下的速度分布和平均流量相比,当微圆管尺寸减小时,空间位形力作用随之增大,其更大程度上影响流体在微圆管内的流动规律;当颗粒呈非球形且最小投影面积相同时,偏离球形颗粒程度越大,空间位形力作用越大,因此空间位形力作用在微小孔道流动中不可忽略.

With the development of liquid production and molecular synthesis technology,the application of soft particle solutions has become increasingly widespread.Soft particle solutions are also used in oil exploitation technology.The soft particles can be elastically deformed through the pores,and the whole process produces a resistance effect on flow.After breaking through the tunnel,the original shape is restored and continuously moved to the deep part of the oil layer.The soft particles do not only block the porous medium but also increase flow resistance.Moreover,they can generate deformation and break through the pores under a certain pressure to reach the depth of the reservoir.The microscopic forces mainly include Van der Waals force,electrostatic force,spatial configuration force,and surface tension.The effect of the spatial configuration force caused by the deformation of the soft particles affected by the tube wall action is considered to address the problem that micron-sized soft particle solutions in microtube deviate from the Poiseuille law.On the basis of Navier--Stokes theory,the flow velocity distribution and flow expression of the polymer solution in the tube were derived.A particle deformation factor was introduced to characterize the effect of the spatial configuration force.A mathematical model of microtube flow was established by considering the spatial configuration force.From the micro-scale flow characteristics experiment,the microtube flow in micron-sized soft particle solution was obtained.As evidenced by the results,when the tube diameter is smaller than the particle diameter,the flow velocity considering the spatial configuration force is closer to the experimental data than the Poiseuille flow under the same pressure gradient.Through the analysis of influencing factors,the spatial configuration force cannot be neglected in the microtube flow.Compared with the Poiseuille flow,the spatial configuration force increases and affects the microtube flow when the microtube size decreases.When the particles are non-spherical and the minimum projected area is the same,the greater the degree of deviation from the spherical particles and the greater the effect of the spatial configuration force.