Study of Flow and Power Characteristics of the Last Compartments of Cogeneration Steam Turbines

The work is devoted to the analysis of approaches to the description of the flow and power characteristics of the last turbine stages and compartments, which are crucial in assessing the efficiency of the operation of turbine units. Its relevance is due to the necessity to improve calculation methods for cogeneration turbine units since they are still the main source of thermal energy in centralized heat supply systems. The purpose of this article is to evaluate modern approaches to describing the power characteristics of stages and compartments of turbines and to develop alternative ways of presenting them to solve existing problems. This goal was achieved due to the fact that a comprehensive generalization of the experimental data obtained during pilot tests of several types of turbine units was carried out in the form of a generalized nonlinear mathematical dependence that is valid for all the last stages and compartments in the entire range of steam flow rates, up to zero. The most important result and the novelty of this work consisted of consideration a universal form of representation of power characteristics made it possible to integrate them into computer models for calculating turbines, conduct detailed numerical calculations based on them and obtain reliable (accurate to 1-3%) results when calculating y variable modes, including ventilation ones. Significance of the obtained results lies in the fact that they make it possible to find reserves for increasing the efficiency of thermal power plants under variable load schedules due to regime and optimization events