TY JOUR TI METHODS OF CENTRIFUGAL PUMPS OPERATION REGULATION KW centrifugal sectional pump KW pressure KW frequency controller KW and hydraulic coupling JO Bulletin of the Angarsk State Technical University AU Podoplelov, E.V. AU Dement'ev, A.I. AU Novackih, I.E. AU Suhorukova, K.I. PY 2025 IS 1 PB Federal State Funded Educational Establishment of Higher Education «Angarsk State Technical University»