Determination of hydraulic steam losses in the turbine control valve based on a three-dimensional model

Abstract

A problem to be solved now is determining the hub nodes of hydraulic losses arising during the operation of power plant equipment. Detection of such points directly by measuring devices on the operating equipment is impossible as it is difficult to access many elements of the flow part of the units. Development of digital models of equipment allows simulating these processes and with a high degree of accuracy determining the location of increased hydraulic losses. The aim of this work is to determine the magnitude and localization of hydraulic losses in the control valve of the steam turbine. The analysis of steam turbine valve operation has been carried out based on thermodynamic, hydraulic and mechanical parameters, which are taken directly during the operation of the power plant by standard control and measuring devices. The obtained information was processed by the finite element method in the Ansys and SolidEdge Flow Simulation programs and by three-dimensional modeling in the SolidEdge software package. We have obtained a three-dimensional model of the control valve and determined the fields of pressure, velocity, etc. distribution in the volume of the control valve under different operating conditions by the finite element method. During the processing of the obtained information, we found excessive energy losses of water vapor arising during its throttling in the control valve. Such losses produce a significant effect on the power developed by the turbine pump. During the operation of the drive turbine, the pressure losses of the working medium in the steam distribution system vary in the range of 300–500 kPa (37–62 % of the initial pressure before the control valve). The goal set in the work has been fully achieved. Verification of the developed three-dimensional model was made on the basis of the operational parameters taken during the steam turbine operation. The application of the work results, both for modernizing the existing units and designing new equipment, will increase the efficiency of electric energy production at the power unit of the station.