In this work, the measurements of the swirling field of continuous phase in a new vane-type pipe separator have been carried out to validate the separation characteristics by the Particle Image Velocimetry. The radial, tangential and axial velocities were obtained. The results show that the new separator can successfully form a symmetrical swirling field. The transition region of the tangential velocity between the free vortex and the forced vortex shows a wider range than that in the traditional hydrocyclone. The axial velocity is always positive from the pipe wall to the central area and appears three-peak distribution. The tangential and axial velocities are dependent to the inlet flow rate, and yet show a low sensitivity to the ratio of flow split when the ratio of flow split is less than 13.1%. These results are helpful to the optimal design of the downhole oil/water separator.

Graphical abstract