No abstract

Hydrodynamic forces in annular seals of centrifugal pumps create a significant effect on the vibrational activity of the rotor as a whole. Theoretical and experimental studies of various authors made it possible to establish the structure of hydrodynamic forces and determine the magnitude of the coefficients of radial forces. The authors of this work obtained quantitative load characteristics of the rotor in an annular seal at specially created laboratory experimental stands at various pressure drops and significant angles of misalignment of the rotor axis relative to the seal axis. Static experiments were also conducted with annular seals of various lengths with a constant differential pressure of the liquid and a fixed angle of misalignment of the rotor axis relative to the axis of the annular seal. The given misalignment angle was obtained as a result of the action of various external forces on the rotor. In addition to static experiments, dynamic rotor tests were carried out. Experimentally obtained amplitude - frequency characteristics of the forced radial - angular oscillations of the rotor, which is dynamically mounted in two symmetrical annular seals. From the experimental characteristics, the critical frequency of the rotor angular oscillations in the seals was determined. According to theoretical formulas, taking into account the value of the coefficient of angular stiffness of the annular seal, the frequency of the natural angular oscillations of the rotor in the annular seals was calculated. A comparison of theoretical and experimental values indicates their good quantitative agreement.

In slotted seals of centrifugal pumps, due to eccentric displacement and angular rotation (skew) of the rotor, deformation of the pressure distribution diagram along the length and perimeter of the seal arises, which gives rise to the resultant main components of the hydrodynamic force: elastic, damping and circulating. The resultant main forces can be transferred to the geometric center of compaction with the formation of the corresponding hydrodynamic moments. These hydrodynamic moments of radial and angular hydrodynamic forces in the slit seal of a centrifugal pump have a significant effect on the dynamic characteristics of the unit in the case when the pump rotor makes coupled radial-angular oscillations. Angular moments are functions of the angles of rotation (skew) of the rotor in the seal. The moment of elastic force creates the angular instability of the rotor in a single seal, but in the presence of two symmetrical gap seals, this moment is compensated by the moments of the resultant elastic forces relative to the geometric center of the entire rotor.

В статті обґрунтовано важливість і актуальність проблеми підвищення робочих характеристик і ресурсу роботи бабітових підшипників ковзання (ПК), які є опорами роторів великої кількости відцентрових насосів, компресорів, турбін та іншого динамічного обладнання, що працює при висо-

Turbo-pumping units (TNA) of reservoir fluid are designed as power machines with internal hydraulic drive in the form of a multistage turbine and pumping part with a powerful axial force unloading system. In this case, the economic feasibility of using them requires the achievement of a high efficiency (efficiency), the main component of which is created by the maximum possible external volumetric efficiency. due to the design of a static stable axial unloading system with the least possible leakage of the working fluid. Its energy contribution to the value of total efficiency gives both pumping and turbine parts of the TNA unit. Calculation of total efficiency is advisable to carry out the TNA method by successive approximations with the fulfillment of the necessary condition for balancing the capacities of the turbine and pump parts, taking into account the external energy losses.