全金属螺杆泵工作特性试验模拟与评价

Experimental Simulation and Evaluation of All Metal Progressing Cavity Pump Performance

全金属螺杆泵的定转子采用间隙配合方式,其工作特性无法沿用传统螺杆泵的相关认识。为此,基于间隙配合方式全金属螺杆泵的结构特点与工作原理,提出了理论排量的修正计算方法;对不同工作条件下的排量、负载和效率等工作特性开展了室内试验研究,绘制了相应的工作特性曲线;结合能量损失评价,提出了保证工作性能的相关方法。分析结果表明:全金属螺杆泵的排量、轴功率及泵效等受工作压差、转速和泵级数等因素的综合影响,特定工况下存在性能最佳的工作区域;适当提高转速以及泵级数可实现较高的工作效率,同时可满足相对更高的举升扬程需求;全金属螺杆泵的容积损失与机械损失随工作压差和转速的变化呈相反变化趋势,但提高转速对容积效率的有利影响明显大于对机械效率的不利影响,实际生产中可将合理选择转速作为保证工作性能的有效途径。所得结论对全金属螺杆泵井的举升设计及实际生产具有一定的参考。

The performance of all metal progressing cavity pump（ PCP） can not completely refer to the knowledge of the traditional PCP owing to adopting the clearance fit between the stator and rotor. In view of this,the modified calculation method of the theoretical displacement is proposed based on the structural characteristics and working mechanism of all-metal progressing cavity pump in clearance fit mode. An experimental study was conducted on the working characteristics such as displacement,load,and efficiency under different working conditions. Corresponding work characteristic curve was attained. Combined with energy loss evaluation,relevant methods to ensure PCP work performance were proposed. The analysis results show that： The displacement,shaft power and pump efficiency of the all-metal PCP are affected by the combined effects of working pressure,rotating speed and number of pump stages. There is a work range with the best performance under specific conditions. Appropriately increasing the pump stages and rotating speed can achieve higher work efficiency while meeting relatively higher lifting head requirements. The volume loss and mechanical loss of the all-metal PCP change reversely with the change of working pressure and rotating speed. But the beneficial effect of increasing the rotating speed on volumetric efficiency is obviously greater than the adverse effect on the mechanical efficiency. Properly selecting the rotating speed could be an effective way to ensure working performance. The study could provide references for lifting design and actual production of all-metal PCP wells.