Life Assessment of Steam Turbine Components Based on Viscoplastic Analysis (original) (raw)
Related papers
Stress Simulation of General Steam Turbine Blade Materials.
International Journal of Engineering Sciences & Research Technology, 2013
In Industries the Turbines are used for converting the forms of energy, the Blades are the key elements for turbines where the blades of the turbines experiences different types of failures. The common reason of these types of failures is the thermal stress which is experienced by the blades. The breakage point of blades depends upon the material used to make it. If we can have thermal stress analysis of the blade materials then it is easy to determine that under different conditions & up to which point, materials can resist. Having this information, a system having turbine can be analysed, according to that materials can be used to make blades. These blades can resist better than any other blades which can be used. In this work, models have been generated based on actual measurement of the blades which are used in industries for steam turbines. Applying the properties of different materials on these models, the simulation of thermal stress has been observed in this paper.
TECHNOLOGY Stress Simulation of General Steam Turbine Blade Materials
2013
In Industries the Turbines are used for convertin g the forms of energy, the Blades are the key eleme nts for turbines where the blades of the turbines experienc es different types of failures. The common reason o f these types of failures is the thermal stress which is experien ced by the blades. The breakage point of blades dep ends upon the material used to make it. If we can have thermal st ress analysis of the blade materials then it is eas y to determine that under different conditions & up to which point , materials can resist. Having this information, a system having turbine can be analysed, according to that material s can be used to make blades. These blades can resi st better than any other blades which can be used. In this work, m odels have been generated based on actual measurement of the blades which are used in industries for steam turbi nes. Applying the properties of different materials on these models, the simulation of thermal stress has been o bserved in this pa...
Engineering Transactions, 2019
The paper presents the results of experimental tests and numerical simulations related with the strength differential effect. Tensile and compression tests on 2CrMoV low-alloy steel are performed to evaluate the magnitude of the yield stress difference in tension and compression. The strength differential parameter is then used in the formula for equivalent stress proposed by Burzynski. The material effort calculated using Burzynski and Huber-Mises-Hencky hypotheses was compared for different start-stop cycles. Analytical notch stress-strain correction rules by Neuber and Glinka-Molski were applied to compute elastic-plastic strain amplitudes in rotor circumferential grooves. It was finally shown that the strength differential effect has significant influence on the predicted fatigue life under thermo-mechanical loading.
Static and Fatigue Analysis of a Steam Turbine Blade
Steam turbine is one of the most important prime movers for generating electricity. This falls under the category of power producing turbo-machines. Single unit of steam turbine can develop power ranging from 1 MW to 1000 MW. The purpose of turbine technology is to extract the maximum quantity of energy from the working fluid, to convert it into useful work with maximum efficiency, by means of a plant having maximum reliability, minimum cost, minimum supervision and minimum starting time. This present work explores the finite element analysis of a steam turbine blade using ANSYS software. Life cycle assessment of steam turbines is essential to improve their design and maintenance plans, since they should operate more than 20 years with minimum interruptions and without failures. Important element of this turbine is the blades and rotor due to their size, mass and cyclic stresses with relatively high frequencies and amplitude. To cope up with this we are using titanium alloy as a material. Different types of loads acting on steam turbine blade and consequential stresses develops in blade are studied. Fatigue stresses are developed on the steam turbine blade due to change in steam speed. The maximum steam speed range (from cut-in to cut-out steam speed) is considered for design of blade as well as predicting the fatigue life of the blade.
Cyclic plasticity behaviors of steam turbine rotor subjected to cyclic thermal and mechanical loads
European Journal of Mechanics - A/Solids
In this paper, shakedown and ratchet analyses are performed to investigate the cyclic plasticity behaviors of the steam turbine rotor subjected to cyclic thermal and mechanical loads by employing Linear Matching Method (LMM). Traditionally, the shakedown or ratchet analysis mainly focus on the structure under general cyclic loading condition composed by constant mechanical load and cyclic thermal load, but the investigated steam turbine rotor here is subjected to cyclic mechanical load and cyclic thermal load that vary in phase and out of phase throughout the practical operation load cycle. The failure behaviours of structure under practical operation load cycle is studied and discussed. The novel shakedown and ratchet failure diagrams are plotted by calculating different combinations of cyclic mechanical load and cyclic thermal load. The innovative equation to acquire plastic strain range of the structure under steady state cycle is fitted, which is vital for low cycle fatigue (LCT) assessment. Moreover, detailed step-by-step inelastic analyses are also performed to verify the applicability and effectiveness of the limit boundaries calculated by the LMM. All the investigations demonstrate that the proposed LMM technique is capable of handling practical industrial application with complicated cyclic loads.
The effect of temperature on strength differential and material effort of steam turbine rotors
3RD NATIONAL CONFERENCE ON CURRENT AND EMERGING PROCESS TECHNOLOGIES – CONCEPT 2020, 2020
The paper presents the results of mechanical tensile and compression tests performed at a range of temperatures on specimens made from 2%CrMoV steel. Variation of strength differential coefficent was found and considered in numerical analyses of material effort of a steam turbine rotor subject to thermomechanical loading. The effect of temperature on strength differential was found to be small for this steel and only little influenced the material effort and fatigue life of the rotor under investigation.
Life span prediction for the last row blade of steam turbine
Environmental Engineering Science, 2021
The steam turbine of Ramin Ahvaz power plant is a k300-240 model manufactured by the Russian power machine company, which has six units of 300 MW. The above turbine has a rotational speed of 3000 rpm; its final blade weight is 9.2 kg. Its centrifugal force causes one of the most important and effective stresses in the blade. In this research, the first step, the forces acting on the blades such as centrifugal force are investigated, and then the stresses of these forces are calculated. By using these calculations and the properties of the blades, estimation of the blade life is made by applying stress-life correction coefficients. In the following, by using an engineering software named ABAQUS, a sample of the last row of fins is simulated. This simulated specimen after meshing is stress analyzed. By this method, the results of manual computations are compared by using different life criteria such as Goodman's and Gerber's life criteria results obtained by Abacus (finite ele...
Archive of Mechanical Engineering, 2016
This paper is concerned with the 1 st stage of HP rotor blade assembly steam turbine TK 120. The methodology was focused on the selection of mechanical properties and the way of the rotor disc modeling and estimating the degree of damage caused by creep. Then the dynamic interference between the frequencies of excitation and the natural frequencies was assessed. Static calculations were performed for the cyclic sectors consisting of the disc, disc blades, spacers and shrouding, including loads as temperature, mass forces from the angular velocity and the pressure on the blades. Then, the creep analysis using a Norton's model and the modal analysis were performed. Static analysis gave information concerning the distributions of displacements, stress and strain components. In the creep analysis, the creep displacements and stress relaxation versus time were determined and the estimated degree of damage caused by creep was evaluated at each part of the rotor disc. In the modal analysis, the natural frequencies and modes of vibrations corresponding to the nodal diameters were found. The results of modal analysis were shown in the SAFE graph. Numerical calculations have shown that the rotor disc was a well-designed structure and did not reveal any dynamic interference.
Analysis of Creep Life of Steam Turbine Blade by Using Different Material
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY, 2014
Turbine Blades are the main component of any steam power plant and have to withstand in very high temperature. The main aim of this paper is to calculate the creep life of 210MW Reheat Reaction Turbine Blade by changing the different material and suggested the best material for the turbine blade, so the life of the turbine blade is increased to some extent. In this paper the modeling of blade is done in PRO-E and analysis of stress is done in ANSYS 14.5 FEA tool. After structural analysis of the turbine blade Modified Larson Miller Parameter is used to calculate the creep life of the turbine blade then the results are compared and finally some of the results are presented.