抽油机井杆管环空瞬态流场煤粉颗粒排出研究

Research on coal particle carrying out in unsteady flow field of rod pumped well annulus

对具有周期性运动边界的抽油机井杆管环空的瞬态固液两相流问题,提出采用动网格技术处理边界和流场内部网格节点运动的方法,保证较高的网格质量作为数值求解流场的前提;建立基于动网格技术的煤粉颗粒和水的固液两相流数学模型,采用基于非结构网格的SIMPLEC算法求解非稳态流场,得到煤粉颗粒瞬态的速度和浓度分布,进而求得杆管环空煤粉的质量流量及不同工况下煤粉颗粒的排出量,并通过排煤粉试验验证了数值计算的准确性。结果表明:抽油杆的往复运动对杆管环空流场产生的扰动作用,使得相同排量不同冲程冲次的抽油机井杆管环空的煤粉排出量不同;排量越小,煤粉粒径越大,煤粉排出量的差异就越大,最大相差达29%。

The annulus between rod and tube in sucker rod pumped well has a moving boundary due to the rod＇s periodic mo-tion, which makes the two-phase flow of coal particle and water become a complicated transient problem. The dynamic meshtheory was adopted to handle the grid node＇s movement both on the boundary and in the flow field. The high quality grid canbe obtained using this method, which is beneficial to precisely solving the unsteady flow field. The mathematical model ofsolid-liquid two-phase flow was solved by SIMPLEC method based on unstructured grid. The coal particle＇s velocity and con-centration were acquired, then the mass flow rates at the inlet and outlet of annulus were gained and the integrals for flux indifferent working conditions were computed. The results show that the coal particle emission is influenced by the rod＇s period-ic motion disturbance, which makes the coal particle clean out change with different stroke and rate of pump, while the pumpoutput volume is a constant. The clean out difference increases while the coal particle diameter increases and the pump outputvolume decreases, and the maximum difference value is 29%.