This paper deals with the study of oil-water emulsions separation processes in the separators with a vortex flow. The authors developed a new design of separator, consisting of Π-shaped elements and, when the liquid moves between these elements, the centrifugal force appears, leading to the layering of oil-water emulsion. The paper includes the numerical studies on the flow structure determination, conducted by means of software package ANSYS Fluent, and allowing us to evaluate the design of separators to achieve the high separation efficiency. It was found that an increase in the actual flow rate, and, as a consequence, the Reynolds number, as well as the height of device lead to an increase in the emulsion separation efficiency. At the same time, the oil concentration at the device outlet can reach 99.9%. The developed device allows to increase significantly the throughput capacity of apparatuses for the oil-water emulsions separation, widely used in the oil-and-gas extraction industry.