The evolution of concentrated particle suspensions in a two dimensional channel flow between parallel plates is considered. We developed a numerical model based on the finite volume method to solve the full unsteady Navier Stokes equations coupled to a constitutive advection-diffusion equation in order to determine shear-induced migration phenomenon in concentrated suspensions of monodisperse and non-colloidal spherical particles in two dimensions. The numerical model predicts the unsteady flow field, particle migration fluxes and gravitational mechanisms responsible of solids transport. The particle migration phenomena was studied in Newtonian and non Newtonian carrier fluids and the code was validated with both Newtonian and non-Newtonian carrier fluids solving the suspension advection-diffusion constitutive equation to determine the volume fraction contribution to the apparent viscosity of the fluid. In the case of a Newtonian carrier fluid the unsteady numerical simulations predicted a particle migration mechanism effectively occurring from high to low shear regions but evolving downstream. A cusped concentration profile was found at the channel centerline accompanied with a wall depletion region where the concentration was below the initial bulk value. The effect of gravity versus particle migration fluxes was studied though the introduction of initial uniform spot-like patches of bulk concentration in particular locations of the channel. For a Newtonian carrier, under the effect of a gravitational flux, the model predicts the formation of a sediment on the channel wall identified by an increase of local concentration similarly to the formation of a bottom bed found in mining slurries. In the case of a non-Newtonian Bingham carrier fluid without gravitational effects, the model predicts symmetrically cusped concentration profiles at the interface between yielded and unyielded regions and a particle depletion region close to each wall, where the particle concentration fall below the bulk concentration.

考虑了在平行板之间的二维通道流中浓缩颗粒悬浮液的演变。我们建立了基于有限体积方法的数值模型，以求解完整的非稳态Navier Stokes方程与本构对流扩散方程的耦合，以便确定二维中单分散和非胶体球形颗粒的浓缩悬浮液中的剪切诱导迁移现象。 。数值模型预测了引起固体输送的非恒定流场，颗粒迁移通量和重力机制。在牛顿和非牛顿载流体中研究了颗粒迁移现象，并用牛顿和非牛顿载流体验证了代码，并解决了悬浮对流-扩散本构方程，以确定体积分数对流体表观粘度的贡献。在牛顿载流体的情况下，非稳态数值模拟预测了颗粒迁移机制有效地发生在从高剪切区到低剪切区，但向下游发展。在通道中心线处发现尖峰的浓度分布，并伴有浓度低于初始体积值的壁耗尽区域。通过在通道的特定位置引入最初的均匀的块状块状块体浓集，研究了重力对颗粒迁移通量的影响。对于牛顿载体，在重力通量的作用下，该模型预测通过局部浓度的增加识别出的通道壁上沉积物的形成，类似于在采矿浆液中发现的底床的形成。在没有重力作用的非牛顿宾厄姆载流体的情况下，该模型预测在屈服区和非屈服区与靠近每个壁的颗粒耗竭区之间的界面处对称尖峰的浓度分布，其中颗粒浓度低于总浓度。该模型通过局部浓度的增加来预测通道壁上沉积物的形成，这类似于在采矿浆液中发现的底部床层的形成。在没有重力作用的非牛顿宾厄姆载流体的情况下，该模型预测在屈服区和非屈服区与靠近每个壁的颗粒耗竭区之间的界面处对称尖峰的浓度分布，其中颗粒浓度低于总浓度。该模型通过局部浓度的增加来预测通道壁上沉积物的形成，这类似于在采矿浆液中发现的底部床层的形成。在没有重力作用的非牛顿宾厄姆载流体的情况下，该模型预测在屈服区和非屈服区与靠近每个壁的颗粒耗尽区之间的界面处对称尖峰的浓度分布，其中颗粒浓度低于总浓度。