不同配合方式螺杆泵的工作特性探讨

Study on Performance of PCPs in Different Fit Modes

应用于油井举升的螺杆泵(PCP)存在传统过盈配合与新型间隙配合两种不同类型,两者工作特性存在显著差异,目前缺乏综合考虑定转子配合情况的螺杆泵工作特性研究。为此,引入配合参数的概念定量化描述定转子的配合情况,基于螺杆泵的基本结构与工作原理,对比研究了不同配合方式下螺杆泵的排量、能耗、效率等工作特性,并系统分析了配合参数对工作特性的影响。实例分析表明,基于不同配合方式的螺杆泵理论排量随配合参数的增大略有减小;过盈配合方式下存在明显的泵内摩擦,能耗特性受过盈值的影响较大,但可实现高于80%的容积效率;间隙配合方式下存在明显的漏失情况,排量特性受间隙值的影响较大,但可实现高于90%的机械效率;特定条件下采用间隙配合方式的螺杆泵具有更大的节能潜力。

There are two kinds of progressive cavity pumps(PCPs)applied in oil wells for artificial lifting,including the traditional PCP in interference fit and the new-type PCP in clearance fit.The PCP performance in different fit modes is significantly various.However,there is still no study on the PCP performance in consideration of the fit condition between the stator and rotor at present.Therefore,the concept of fit parameter was introduced to quantitatively describe the fit condition between the stator and rotor.A comparative study was carried out on performance characteristics of PCPs(including displacement,power consumption,work efficiency),basing on their basic structures and working principles.In addition,the influence of the fit condition on the pump performance was discussed.The example analysis shows that the theoretical displacement in different fit modes slightly decreases with the increase of the fit parameter;though there is obvious friction in the pump and the interference value has a great impact on power consumption in interference fit,it s able to achieve high volumetric efficiency(>80%);though there is inevitable leakage and the clearance value has a significant influence on displacement in clearance fit,it s able to achieve high mechanical efficiency(>90%);the PCP in clearance fit has greater energy-saving potential under certain working conditions.