FLOW STRUCTURE TRANSFORMATION AND ENERGY PERFORMANCE OF A TORQUE-FLOW PUMP UNDER PARTIAL-LOAD CONDITIONS (Q = 0.05–0.6 QNOM)

Abstract

The research presents the results of a numerical investigation of the operating characteristics of a torque-flow pump SVN 80-32 in the low-flow range Q = 0.05–0.6 Qnom. The aim of the study is to determine the regularities of changes in head and energy performance indicators and to identify the transformation features of the internal flow structure under partial-load conditions. The simulations were performed in ANSYS CFX using a steady-state formulation and the k–ε turbulence model. Two impeller configurations, single-tier and double-tier, were analyzed. Integral characteristics H(Q) and η(Q) were obtained, and variations of total head, consumed power, and hydraulic efficiency within the investigated flow range were determined. The results show that in the partial-load zone the head remains relatively stable, while the efficiency significantly decreases due to intensified internal recirculation and increased hydraulic losses in the vortex chamber. At Q = 0.05 Qnom a stable circulatory flow structure is formed, maintaining head generation despite severe efficiency degradation. The double-tier impeller demonstrates slightly higher efficiency values in the upper part of the investigated flow range. The obtained results may be used to substantiate rational operating limits and to improve the design of torque-flow pumps operating under variable flow conditions.