This study presents numerical simulations for particle-laden gas–solid flows in horizontal circular pipes to identify the key flow regimes as a function of the main dimensionless parameters. A Euler–Lagrangian approach is employed, using direct numerical simulations (DNS) coupled with a Lagrangian particle tracking (LPT) method, to consider the drag, gravitational and lift forces on particles, as well as the effect of inter-particle collisions. The influence of the Stokes number ($Sk$), mass loading ratio (${\Phi }_m$) and Froude number ($Fr$) on critical flow regimes is assessed to identify conditions under which gravity bias becomes either negligible or dominant with regard to fluid characteristics and particle statistics. Three different regimes of the flow behaviour are identified, depending on the combination of these dimensionless parameters. These flow regimes are described and their dependence on these three parameters ($Sk$, ${\Phi }_m$ and $Fr$) is reported, including the significance of gravity in generating a bias on distributions of the flow statistics.

本研究提供了水平圆形管道中含颗粒气固流的数值模拟，以确定作为主要无量纲参数的函数的关键流态。采用欧拉-拉格朗日方法，使用直接数值模拟 (DNS) 与拉格朗日粒子跟踪 (LPT) 方法相结合，以考虑粒子上的阻力、重力和升力，以及粒子间碰撞的影响。斯托克斯数的影响（$秒克$), 质量负载比 (${\Phi }_{米}$) 和弗劳德数 ($Fr$) 对临界流态进行评估，以确定在流体特性和粒子统计方面重力偏差变得可以忽略不计或占主导地位的条件。根据这些无量纲参数的组合，确定了三种不同的流动行为状态。描述了这些流态及其对这三个参数的依赖（$秒克$, ${\Phi }_{米}$ 和 $Fr$) 被报告，包括重力在产生流量统计分布偏差方面的重要性。