Papers by Keyword: Turbine-Rotor

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Authors: Woo Sung Choi, Eric Fleury, Gee Wook Song, Jung Seob Hyun
Abstract: An important characteristic of a steam power plant is its ability to maintain reliability and safety of the plant against frequent start-ups and load changes. Transient regimes arising during start-ups, shut-downs and load changes give rise to unsteady temperature distribution with time in steam turbine rotor(HP/IP), which results in non-uniform strain and stress distribution. The rapid increase of temperature and rotational speed during starts-ups, especially, makes conditions more severe and causes main components’ damage and reduction of life span for steam turbine. Thus accurate knowledge of thermal and centrifugal stresses are required for the integrity and lifetime assessment for the turbine rotor. So far, only elastic calculations are currently performed for simplicity. However, it is well known that the materials of steam turbine rotor deform inelastically at high temperature. Existing models proposed to describe the viscoplastic(rate-dependent) behavior are rather elaborate and difficult to incorporate with computer simulations in the case of complex structures. In this paper, the life assessment for steam turbine rotor was established by combining the inelastic behavior and the finite element method. The inelastic analysis was particularly focused on viscoplastic behavior that is simple enough to be used effectively in computer simulation and matches the essential features of the time-dependent inelastic behavior of materials reasonably well for cyclic loading under non-isothermal conditions. Using this study, life consumption of steam turbine rotor can be obtained.
Authors: Yan Zhao, Shi Yu Yang, Hao Ran Liu, Bin Liu, Jing Shao
Abstract: Molecular pump with magnetic suspension is an important vacuum extractor. The machining accuracy of turbine-rotor has crucial influence on the key parameters of molecular pump, such as pumping speed, compression ratio. A clamping accuracy detection and display system of semi-fished turbine-rotor was established. The maximum coaxiality error and its position could be detected, displayed and recorded easily. With a precision fine tuning device, coaxiality error could be reduced from 30µm to 10µm. This system effectively reduces the turbine-rotor’s centrifugal force, and increases the stability of molecular pump with magnetic suspension.
Authors: Gee Wook Song, Bum Shin Kim, Jung Seob Hyun
Abstract: The operation mode of thermal power plants has been changed from the base load to duty cycle. From the changeover, fossil power plants cannot avoid frequent thermal transient state, for example, start up and stop, which results in thermal fatigue damage at the heavy section components. The rotor is the highest capital cost component in steam turbine and requires long outage for replacing the new one. For optimized power plant operation life and inspection management of rotor is necessary. It is known as general that start-up and shutdown operation greatly affect on steam turbine life. The start-up operation condition is especially severe because of the rapid temperature and rotational speed increase, which causes damage and reduction of main components life of steam turbine. The start-up stress of rotor which is directly related life is composed of thermal and rotational stresses. The thermal stress is due to the variation of steam flow temperature and rotational stress is due to the rotation speed of itself. In this paper, the analysis method of start-up stress of rotor which considers simultaneously temperature and rotation speed transition is proposed, which includes a case study regarding 500MW fossil power plant steam turbine rotor. Also, the method of damage quantitative estimation of fatigue damage to operation condition is described. The method can be applied to find weak points to the fatigue damage. Using the method, total life consumption can be obtained, and can be also used for determining future operation mode and the life extension of old fossil power units.
Authors: Na Jun Wang, Xiang Wang Jin, Jie Wang, Hai Long Diao
Abstract: This paper establishes the workflow of ANSYS parameterized finite element analysis, based on this, the parameterized finite analysis system of turbine rotor thermal deformation is established. In this analysis system, to complete the analysis process, staff only needs to click on the buttons on the interface and input parameters. The results show that this method can avoid repetitive operations, improve the efficiency and this simple system is easily applied in the factory.
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