Oil-water separation plays a serious role in oil exploitation to reduce the production cost. Centrifugal separation is one of the feasible methods due to its large capacity, high separation efficiency and low maintenance cost. Besides, the centrifugal separation equipment can be divided into tangential inlet separators and axial inlet separators. The ones with tangential inlet have received a large number of investigation on structure optimization but some shortcomings limit the further improvement of separation performance. In this paper, an axial separator with multiple-stage separation was introduced and investigated experimentally with water flow rate range from 3 to 7 m³/h and inlet oil fraction below 10%. Additionally, the schedule for Light Phase Outlets (LPOs) was studied experimentally and theoretically to ensure high separation efficiency and low split ratio. The results show that the multiple stage separator can keep high separation performance that the oil concentration in HPO is below 200 ppm while the split ratio ranged from 0.2 to 0.45 within experimental conditions. Besides, the reasonable schedule can lead an obvious drop in split ratio with high separation performance. Additionally, based on the analysis of flow field characteristic, the LPOs positioned in the two sides of the oil core can ensure the discharge of oil droplets in high swirl flow field and the LPO located downstream has better potential to separate small size droplets.

油水分离在石油开采中起着重要的作用，以降低生产成本。离心分离由于其容量大，分离效率高和维护成本低而成为可行的方法之一。此外，离心分离设备可分为切向入口分离器和轴向入口分离器。切向入口的分离器已经得到了结构优化方面的大量研究，但是一些缺点限制了分离性能的进一步提高。本文介绍了一种具有多级分离功能的轴向分离器，并在水流量为3至7 m ^3的范围内进行了实验研究。/ h，且入口油分低于10％。此外，还通过实验和理论研究了轻相出口（LPO）的时间表，以确保高分离效率和低分流比。结果表明，在实验条件下，多级分离器可以保持较高的分离性能，即HPO中的油浓度低于200 ppm，而分流比在0.2至0.45的范围内。此外，合理的排产时间会导致分离比明显下降，分离性能高。此外，基于流场特性的分析，位于油芯两侧的LPO可以确保在高旋流流场中排出油滴，而位于下游的LPO具有更好的分离小液滴的潜力。