A numerical investigation of lateral migration of a neutrally buoyant particle in Couette flow with two different thermal boundary conditions is performed using a lattice Boltzmann method coupled with a discrete element method. The effects of the channel Reynolds number (Re), the Grashof number (Gr) as well as the particle size on the migration behaviour are explored in detail. It was found that when both the top and bottom walls are hot, the equilibrium positions are located below the centerline for all the particle sizes studied, which can be well characterised using a dimensionless force ratio determined by the Richardson number (Ri=Gr/Re²) and the confinement ratio. With the increase of the force ratio, the equilibrium position moves towards the bottom wall. On the other hand, when the top wall is cold and the bottom wall is hot, a transition of the equilibrium position is observed, which switches from below the centerline to above the centerline as the particle size is increased above a certain threshold. It is discovered that the critical Reynolds number at transition can be well described by a power law of the confinement ratio. Furthermore, it is also found that the variation of the equilibrium positions above the centerline is governed by a new dimensionless parameter Gr/Re for a fixed particle size, which is attributed to the finite size effect.

使用格氏玻尔兹曼方法与离散元方法相结合，对具有两种不同热边界条件的库埃特流中中性浮力颗粒的横向迁移进行了数值研究。详细探讨了通道雷诺数（Re），格拉斯霍夫数（Gr）以及粒径对迁移行为的影响。结果发现，当顶壁和底壁都很热时，所有研究粒径的平衡位置都位于中心线以下，这可以通过由理查森数确定的无因次力比来很好地表征（Ri = Gr / Re ^2个）和限制比率。随着力比的增加，平衡位置向底壁移动。另一方面，当顶壁是冷的而底壁是热的时，观察到平衡位置的转变，当粒径增加到某个阈值以上时，该平衡位置从中心线下方切换到中心线上方。发现临界的雷诺数可以由约束比的幂定律很好地描述。此外，还发现，中心线上方平衡位置的变化由固定尺寸的新无量纲参数Gr / Re控制，这归因于有限尺寸效应。