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Journal ArticleDOI

Finite element analysis of the three-dimensional transient temperature field in steam turbine casings

TL;DR: In this paper, the 3-D transient temperature distribution in the turbine casing metal has been computed using finite element analysis and the results obtained by a code developed for a specific type of turbine casing have been compared with the values measured by experiment and have been found to validate the code.
About: This article is published in International Journal of Mechanical Sciences.The article was published on 1993-07-01. It has received 3 citations till now. The article focuses on the topics: Casing & Turbine.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a constitutive creep model based on continuum damage mechanics and a multiaxial creep strain formula was used to describe the stress-strain behavior of a 1000MW supercritical steam turbine.

8 citations

Journal ArticleDOI
TL;DR: In this article, the Ramberg-Osgood model and Manson-Coffin strain-life law were used to describe the stress-strain behavior and calculate the damage.
Abstract: The fatigue behavior of a specific inner casing of a 1000 MW supercritical steam turbine was investigated during a complete startup phase. The Ramberg–Osgood model and Manson–Coffin strain-life law were used to describe the stress–strain behavior and calculate the damage. The temperature variation during the startup phase revealed that the startup phase could be divided into a warming-up phase, transition phase, and elevated temperature phase. The thermal stress that dominated in the inner casing could also be divided into the same three phases. The damage caused by the alternating stress during the warming-up phase was around 70% of the total damage. The remaining 30% of the damage was contributed by the transition and elevated temperature phases. The fatigue life was improved by shortening the warming-up phase and extending the elevated temperature phase. The damage was reduced by approximately 20%.

3 citations

Journal ArticleDOI
TL;DR: In this article, the stress-strain state problem for the inner casing of a steam turbine high-pressure cylinder operating at supercritical steam parameters (over 240 atm and 565 °C) is solved by using a finite element software package.
Abstract: A structure’s material plasticity influence on the pattern of contact interaction of its elements during operation is studied. The stress-strain state problem for the inner casing of a steam turbine high-pressure cylinder operating at supercritical steam parameters (over 240 atm and 565 °C) is solved. The problem is solved by using a finite-element software package. A model of thermoplasticity with kinematic and isotropic hardening is considered. In carrying out the study, experimental strain curves were used for the materials of the connection. The main dependencies used in solving the problem are given. The method of solving the thermal contact problem of interaction of flange connector elements in the conditions of plasticity is based on the application of a contact layer model. To be able to take into account changes in the load from the fastening in the process of combined strain of both the fastening and the casing, first proposed is a method of the three-dimensional modeling of the thermal tightening of the fastening of the horizontal casing connector by applying the linear coefficient of linear expansion of the material. The proposed approach allows modeling the stress of the initial tightening of studs by specifying a fictitious change (decrease) of the coefficient of linear expansion of a stud given as a separate body in the calculation scheme. The magnitude of the specified change in the coefficient of linear expansion is determined from the relationship between the stress of the initial tightening in the stud and the required, for its creation, elongation, which is implemented in the calculation scheme in the presence of different values of linear expansion of both the stud and the casing. To conduct the numerical experiment, an ordered finite-element grid of the casing design was constructed. A 20-node finite element was used in the construction of the casing grid and the fastening. The effect of force loads and the temperature field, in which the structural element under consideration is operated, is taken into account. An analysis of the results of distribution of equivalent stresses and contact pressure during operation is carried out. The difference between the obtained results and the results of solving the problem in the elastic formulation is noted.

1 citations

References
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Paul Hood1
TL;DR: A frontal solution program is presented which may be used for the solution of unsymmetric matrix equations arising in certain applications of the finite element method to boundary value problems based on the Gaussian elimination algorithm.
Abstract: A frontal solution program is presented which may be used for the solution of unsymmetric matrix equations arising in certain applications of the finite element method to boundary value problems. Based on the Gaussian elimination algorithm, it has advantages over band matrix methods in that core requirements and computation times may be considerably reduced; furthermore numbering of the finite element mesh may be completed in an arbitrary manner. The program is written in FORTRAN and a glossary of terms is provided.

433 citations