Dans le cadre d’un projet Nadya financé par l’Institut Français d’Ukraine, la Cdefi et le Labex, nous accueillons le Professeur Andriy Zahorulko de Sumy State University en Ukraine au sein de l’Institut Pprime pour une période de 2 mois.
Il donnera un séminaire intitulé « Improving the sealing, lubrication, and balancing of centrifugal machine rotors with highly efficient seal and bearing designs » le 20 novembre 2025 à 14h dans la salle de réunion du D3 (1W68), batiment SP2MI H1:
Abstract:
One of the most energy-intensive types of modern equipment is dynamic equipment, such as centrifugal pump and compressor units and turbines. As is known, the operating parameters of centrifugal machines are limited by the load-bearing capacity, friction losses, volume losses and vibration state of the rotor system, which are determined by the static and dynamic characteristics of the annular and mechanical seals and bearings. Static characteristics are determined by the design and hydrodynamic properties of the lubricating fluid. Dynamic properties of seals and bearings depend on the operating and geometric parameters, changing which can influence the rotor vibrations in the desired direction. Leakage in seals is limited by losses of potential pressure energy to overcome local resistance and friction resistance along the length of the channel. The greater these losses, the smaller the fraction of potential energy is converted into kinetic energy of the flow, the smaller the leakage into the environment and energy losses in the centrifugal machine.
The scientific work is devoted to solving the scientific and technical problem of sealing, lubrication and balancing rotors of centrifugal machines by using new highly efficient designs of annular and mechanical seals and bearings and constructive methods of increasing their stiffness characteristics and damping properties.
The results of experimental and theoretical studies of various designs of annular, labyrinth and scallop damper seals, face packing seals with hydrodynamic friction pair unloading, face impulse seals, thrust sliding and rolling bearings are considered. The presented numerical calculation methods are based on the methods of computational mechanics for analyzing the nature of the flow, thermal, stress-strain and dynamic state of seals and bearing of centrifugal machines. The analysis of static and dynamic characteristics, the magnitude of leakages and hydrodynamic forces, dynamic stiffness and damping coefficients and load-bearing capacity is presented. The experimental rigs and the results of theoretical and experimental studies of two-stage face impulse seals with coaxial arrangement of stages for centrifugal pumps and compressors are considered. A numerical analysis of the static and dynamic characteristics of non-contact mechanical seals with grooves of various topologies is carried out. A new promising design of the balancing device of a multi-stage centrifugal machine, which simultaneously performs the functions of a hydraulic buffer and a radial-axial bearing, is considered. The static and dynamic characteristics of a direct-acting difference pressure regulator for a dry gas seal system are presented. Practical recommendations are given for the design of reliable seals and bearings of a wide class of centrifugal machines.
Biography:
Andriy Zahorulko received his Doctor Engineer Diploma (PhD, Engineering) from Sumy State University (Ukraine) in November 2001. He performed postdoctoral research at Sumy State University in 2005-2008. In December 2008, he received the academic title of associate professor. From September 2014 to the present time, he has been the head of the department, first of General Mechanics and Machine Dynamics, and since July 2021 – of Volodymyr Martsynkovskyy Computational Mechanics. In July 2025, he received the academic title of professor of Computational Mechanics Department of Sumy State University. During his scientific activity, he had scientific internships in Silesian University of Technology (Gliwice, Poland), University of Stuttgart (Stuttgart, Germany), Texas A&M University (College Station, USA), Institute PPrime of University of Poitiers (Poitiers, France) and Korea Institute Science and Technology (Seoul, Republic of Korea).
He is specialized in analytical and experimental investigations and numerical simulations in seals and bearings lubrication and rotordynamics. He has authored or co-authored more than 130 publications (58 in refereed scientific journals, 29 papers indexed in Scopus and Web of Science databases), more than 30 talks at International Conferences.