Analysis of Thermodynamic and Condensation Processes in the Low-Potential Section of Steam Turbines and Approaches to Improving Their Efficiency
DOI:
https://doi.org/10.15407/scine22.02.032Keywords:
last stages of the steam turbine unit, exhaust pipe, condenser, thermoelectrophysics, electrized and ionized wet steam, dielectric permittivity.Abstract
Introduction. Improving the efficiency of the low-potential section of high-capacity wet steam turbine units, which substantially influences the overall turbine performance, remains a critical engineering challenge. Despite the application of advanced modeling and design methods, there still have been understudied issues.
Problem Statement. This study addresses the justified identification of non-conventional methods for reducing additional energy losses that arise specifically in the low-potential section of steam turbines, namely in the final stages of low-pressure cylinders (LPCs), where phase transitions and moisture formation occur. Particular attention has been given to the influence of wet-steam flow electrization on thermodynamic and condensation processes.
Purpose. The purpose of this study is the development of a methodology for improving the efficiency and operational reliability of the low-potential section of high-power steam turbine units through targeted control of thermoelectrophysical processes.
Materials and Methods. The study has examined electrized and ionized wet steam using a combination of literature analysis and experimental investigations. Experimental studies have been conducted on a thermodynamic test bench at the Institute of Power Machines and Systems of the National Academy of Sciences of Ukraine. Full-scale experiments have been carried out at thermal power plants (TPPs) and combined heat and power plants (CHPPs) in Ukraine and the United States. The analytical framework is based on the classical laws of thermodynamics of complex systems, electrophysics, and turbomachinery theory.
Results. Based on computational and experimental investigations, the study has demonstrated positive effects of targeted control of electrophysical influences acting from the final LPC stages through the exhaust system to the condenser. The steam ionization and the application of a constant electric field at the condenser inlet have been proposed respectively, for reducing losses associated with supercooling and for increasing the heat load, improving the uniformity of the velocity field, as well as for neutralizing downstream of the final stage to decreases exhaust pressure and to enhances heat transfer.
Conclusions. The research has shown that improving thermoelectrophysical processes in the low-potential section of steam turbine units can increase their operational efficiency by approximately 1.5—2%
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