集束式扩孔气动冲击器排屑性能的仿真研究

Simulation analysis on the cuttings removal performance of a bundling-reaming pneumatic impactor

为了研究集束式扩孔气动冲击器的排屑性能。建立了其排屑流场模型,运用计算流体力学理论和FLUENT仿真软件,对气固两相流场进行仿真计算,并进一步分析冲击器不同钻进速度和尾气质量流量对其排屑能力的影响,得到排屑流场气相特性规律,岩屑分布规律,不同钻进速度和入口气相质量流量下的颗粒浓度分布。研究结果表明:冲击器排气孔尾气进入排屑流场后流速降低,流场压力由入口到出口呈梯度分布且逐渐降低;岩屑颗粒向流场底部聚集,颗粒平均浓度沿着远离入口方向变化不大,最大浓度沿着远离入口方向逐渐下降,最终趋于平稳;施工时最大钻进速度应低于8.4m/h,增大尾气质量流量排屑能力增强。

In order to study the cuttings removal performance of a bundling-reaming pneumatic impactor,a cuttings flow field model was established,the computational fluid dynamics theory and FLUENT simulation software were employed to simulate the gas-solid two-phase flow field and the impact of different drilling speed and the mass flow of exhaust gas on the cuttings removal performance were analysed.The gas phase characteristics,the distribution of debris flow,the particle concentration distribution under different drilling velocity and inlet gas flow rate were discussed.The results show that:once the exhaust enters into the field,its speed will slow down,the field pressure will maintain in a gradient distribution and gradually decrease from the entrance to exit;cuttings particles will be gathered around the bottom and there is minor variation in their average concentration as they are distributed in the contrary direction against the entrance,while the maximum concentration descends along the same direction and finally becomes stable;during construction,the maximum drilling speed should be less than 8.4 m/h,as the mass flow rate of exhaust gas increases,the carrying ability increases as well.