<b>Abstract</b>— <p>The design of vortex devices for carrying out various heat- and mass-transfer and separation processes should ensure the achievement of maximum efficiency with minimum energy costs; therefore, the task of determining their hydraulic resistance is relevant both in the development of new devices and improving existing technological installations and when solving the problems of optimizing their operation. The paper presents a method for calculating the hydraulic resistance of vortex devices based on the scheme of a centrifugal nozzle, according to which the medium is considered ideal and the flow in the nozzle is potential, with a break in flow continuity along the surface of the vortex radius. The calculation area is divided into three characteristic zones: the forward flow at the entrance to the device, the torsional flow at the outlet of the device, and the outflow of the swirling flow. Dependences are provided for each zone to determine the total pressure. A calculated relationship is obtained to determine the coefficient of hydraulic resistance of devices with moderate flow twist, which is determined by the coefficient of flow twist, the relative radius of the flow rupture surface, and the geometry of the swirler. The results of calculation of the coefficients of hydraulic resistance of vortex-type devices in the critical (on the basis of the maximum flow rate principle) and subcritical modes of flow (according to the condition of minimum kinetic energy of swirled flow and the condition of potential of flow) are presented. Comparison of the calculation results with experimental data show that the obtained relationship is universal and suitable for calculating the coefficient of hydraulic resistance of devices with swirling gas flow, when the influence of the dispersed phase on the hydraulic resistance of devices can be neglected.</p>