Characteristics of the Steam Flow in the End Seals of High Pressure Cylinders in the State of Vacuum Augmentation
DOI:
https://doi.org/10.20998/2078-774X.2016.08.17Анотація
The algorithm was developed to determine steam parameters in the front and back end seals in the mode of vacuum augmentation based on A. Stodol approach that allows us to take into account the steam leakage from the chambers with drainages and determine flow characteristics in each chamber. The steam flow behavior was determined for each section of the end seals of high pressure cylinder (HPC) of the turbine К-325-23.5 at the stage of the preparation for the hot and cold starting. Steam flow characteristics were determined taking into consideration hydraulic resistance of the steam pipelines of drainage system in the time interval of turbine heating of 0 to 2 hours. Forty minutes before the rotor push the steam is injected through the exhaust pipeline at a pressure of 0.6–1.0 MPa and a temperature of 290 to 350 °С. This steam enters the unheated rotor sections of HPC in the region of end seals. Pressure distributions and steam flow consumptions in the section of front and back end seals are indicative of the irrational circuit of rotor heating and the possibility of formation of high thermal stresses. The data analysis shows that a more rational circuit is required for the rotor heating in the region of the front end seal. Using calculated steam parameters heat emission coefficients were calculated for single-phase and two-phase steam flows on the HPC rotor surface in the region of end seals for subsequent thermal strength analysis.Посилання
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