Steady State of Motion of Two Particles in Poiseuille Flow of Power-Law Fluid.

The steady state of motion of two particles in Poiseuille flow of power-law fluid is numerically studied using the lattice Boltzmann method in the range of Reynolds number 20 ≤ ≤ 60, diameter ratio of two particles 0.125 ≤ ≤ 2.4, and power-law index of the fluid 0.4 ≤ ≤ 1.2. Some results are validated by comparing with other available results. The effects of , and on the steady state of motion of two particles are discussed. The results show that, for two particles of the same diameter, the particle spacing in the steady state is independent of . In shear-thinning fluid, increases rapidly at first and then slowly, finally approaching a constant for different . In shear-thickening fluid, although tends to be stable in the end, the values of after stabilization are different. For two particles of different sizes, does not always reach a stable state, and whether it reaches a stable state depends on . When the small particle is downstream, increases rapidly at first and then slowly in shear-thickening fluid, but increases rapidly at first and then decreases slowly, finally approaching a constant in a shear-thinning fluid. In shear-thinning fluid, the larger is, the smaller is. In shear-thickening fluid, has no effect on in steady-state. When the large particle is downstream, increases rapidly at first and then slowly in shear-thinning fluid but increases rapidly at first and then decreases in a shear-thickening fluid. The effect of on in the steady state is obvious. In shear-thinning fluid, increases rapidly at first and then slowly, the larger is, the smaller is. In shear- thickening fluid, will reach a stable state.