空气钻井环空气固两相流动规律数值模拟

Numerical Simulation of Gas-Solid Two-phase Flow Law in Air Drilling

基于FLUENT软件中Euler模型,采用有限容积法建立了空气钻井环空气固两相流三维计算模型,分析了压力分布规律、流体分布规律、浓度分布规律。研究表明,从井底到井口压力逐渐降低;速度在钻铤内逐渐增大,在交界面处迅速降低,而后在钻杆内呈现增大趋势,岩屑速度在整体环空内逐渐降低;在交界面处形成漩涡,对岩屑进行了不同程度的清洗;同时空气浓度达到最大值、岩屑浓度为最小值;随着入口空气的逐渐增加,空气速度、岩屑速度变化率逐渐增大,而交界面处高空气浓度、低岩屑浓度区域逐渐增大,能较大程度的清洗岩屑。

Based on the Euler model in FLUENT software, three-dimensional numerical model of gas-solid two-phase flow in air drilling was established by finite volume method. The pressure distribution law, the fluid distribution law and the concentration distribution rule were analyzed. The results show that the pressure reduces ：gradually from the bottom hole to the wellhead; the velocity gradually increases in the drill collar and quickly decreases at the interface, and then shows a increase trend in the drill pipe, and the cuttings speed gradually reduces in the overall annulus; the cuttings are cleaned at different degrees by the vortexes formed at the. interface; the air concentration reaches the maximum and cuttings concentration reaches minimum at the same time; With the gradual increase of the inlet air, the change rates of air velocity and cuttings speed gradually increase, and the regions of high air concentration and low cuttings concentration gradually expand, which can lead to a greater-degree cleaning of the cuttings.