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The objective of the study is to develop recommendations for accounting during the design stage and the feasibility of operating a magnetic fluid seal with a significant eccentricity of the rotating shaft relative to stationary pole attachments. This goal is achieved through conducted experi-mental research, the selection of necessary equations, boundary conditions, assumptions, and physical properties of the magnetic fluid when constructing a numerical mathematical model of the working gap of the magnetic fluid seal. The most important results of the study include ob-tained and analyzed distributions of the magnetic field, velocity field, and pressure in the mag-netic fluid, as well as the evaluation results of the impact of absolute and relative shaft misa-lignment in the magnetic fluid seal, centrifugal forces arising during shaft rotation, on the re-tained pressure drop by the seal. A significant reduction in the retained pressure drop occurs at an eccentricity of up to 40% of the working gap, and with further increases in eccentricity, the rate of pressure drop reduction slows down. The significance of the results lies in the potential utilization of the provided numerical model, as well as the outcomes of physical and mathemati-cal experiments, in the development of a magnetic fluid seal operating with significant misa-lignment between the rotating shaft and the housing. The dimensionless dependencies obtained allow for consideration, during the design stage, of the reduction in retained pressure drop with shaft eccentricity, taking into account the magnitude of the working gap, magnetic induction, and linear velocity.

The aim of the work is to create an interconnected numerical model of the magnetic, hydrody-namic and temperature fields of a ferrofluid sealer and to analyze thermal processes occurring in high-speed seals. This goal is achieved by selecting the necessary equations, boundary condi-tions, assumptions and physical properties of the magnetic fluid when building the numerical model of the sealer’s working gap, verification of the developed model by the results of the physical experiment. The important results of the work are the obtained and analyzed data on the influence both of physical properties and the geometry of the working gap of the ferrofluid sealer on the heating of the ferrofluid. With a shaft radius of 140 mm and a linear velocity at the shaft surface of 25 m/s due to viscous heating the ferrofluid temperature exceeding the ambient temperature can reach values up to 80 degrees and higher, it has been shown. The use of the equation proposed by V.E. Fertman to determine the thermal conductivity of ferrofluid and the mixing rule to determine its heat capacity allows us to describe with sufficient accuracy for en-gineering calculations the thermophysical properties of concentrated ferrofluids, it was shown. The significance of the results consists in the possibility of using the developed numerical model in the study of interrelated physical processes in the working gap of the ferrofluid sealer of ro-tating shafts. The physical and concentration parameters of the synthetic oil-based magnetic fluid given in the paper and the results of its test operation as part of a ferrofluid seal can be used to verify the results of newly developed models of ferrofluid devices.