Effect of Laser Process on Microstructure and Fatigue Resistance of Steam Turbine Blade

The steal turbine blades, operating in steam electricity production plants are subjected to periodic circular stresses that cause fatigue failure with the passage of time. The chemical composition so steam turbine blades show that is steel 52 it has a wide range of applications, mostly in welded construction, All kinds of welded construction, wind turbines, load-lifting equipment, platform components, cranes, bridge components, and structures. This research aims to study the microstructure of these turbine blades before and after the occurrence of fatigue, and for the purpose of improvement the fatigue resistance, the blades were treated with a laser and the amount of improvement in fatigue resistance was calculated and also the change in the microstructure after laser treatment was studied. The remelting process applied with this parameter Pulse energy = 8 joules, Pulse width = 4.5 Ms., Pulse frequency = 12 Hz, Laser Average Power = 96 W, Laser peak power = 1.78 KW. The results show, after remelting process the microstructure of the specimen is smooth and increase the cyclic of fatigue comparison with specimen without leaser remelting process. So, the fatigue resistance is increased.

Determination of the response surface by strength and vibration parameters of the steam turbine blade

The work is devoted the definition of the function of limiting the geometric parameters of the steam turbine blade at given external loads. For this, a geometric model of a steam turbine blade was created, consisting of a blade body, a shank, and a shroud. The variable parameters were the angle of rotation of the middle section relative to the center of mass (which varied from 87 degrees to 92 degrees), as well as the length of the blade (varied from 495 mm to 525 mm). At the next stage, a finite element mesh was created. For the constructed model, an ordered finite element mesh was created in the area of the blade. Determined the stress-strain state of the blade during the operating mode. When carrying out the static analysis, an rotation velocity of 50 Hz was used as a load, and at the point of attachment of the disk in the shank, fixed displacement of all directions were used. The equivalent von Mises stresses and displacement in the structure are obtained. The zone of maximum stresses is located at the point where the blade is attached to the shank, but they do not exceed the limits. To determine the vibration characteristics of a steam turbine blade, its modal analysis was carried out taking into account the prestressed state from the action of static loads. The first six eigen modes of a steam turbine blade are obtained under the indicated initial conditions. The eigen frequency corresponding to the first form coincides with the rotational velocity (equal to 49 Hz), and the subsequent ones correspond to the multiplicities, respectively. At the next stage, a series of calculations was carried out to determine the response surface for the given parameters. The response surface for the maximum von Mises stresses and the first 4 modes of natural vibrations are determined. On the basis of the obtained results of studies of oscillations and deformed state of the blades with varying input parameters, it is possible to obtain a constraint for solving the optimization problem.

Design and Analysis of Steam Turbine Rotor Blade

A steam turbine is a tool that extracts thermal electricity from pressurized steam and makes use of it to do mechanical work on a rotating output shaft. The steam turbine offers the better thermodynamic performance with the aid of the usage of a couple of levels inside the growth of steam. The levels are characterized by using the manner of strength extraction from them is considered as impulse or reaction mills. On this work the parameters of steam turbine blade various and evaluation is carried out for electricity, existence and warmth switch fees. The varied parameters are the ratio of x-axis distance of blade profile with the aid of chord length and ratio of maximum peak of blade profile in y-path to the chord period. The three-D modeling is executed by way of using Catia software program. The Ansys software is used for static, thermal analysis, subsequently concluded the best design and material (haste alloy, chrome steel, inconel 600) for steam turbine blade, after steam turbine blade imported the stl record 1:2 ratio in to 3-d printing we carried out fast prototyping technique. Keywords: Steam Turbine, Thermal Energy, Impulse Turbine, Reaction Turbine, Static Analysis, Thermal Analysis

Failures of Turbine Components

This article focuses on common failures of the components associated with the flow path of industrial gas turbines. Examples of steam turbine blade failures are also discussed, because these components share some similarities with gas turbine blading. Some of the analytical methods used in the laboratory portion of the failure investigation are mentioned in the failure examples. The topics covered are creep, localized overheating, thermal-mechanical fatigue, high-cycle fatigue, fretting wear, erosive wear, high-temperature oxidation, hot corrosion, liquid metal embrittlement, and manufacturing and repair deficiencies.

Reconstruction of a Steam Turbine Blade Using Piecewise Bernstein Polynomials and Transfinite Interpolation

Turbine blades are designed to achieve its maximum efficiency, but deformations caused by the exposition to extreme operating environments provokes reduction in the engine performance. Often, operators choose to repair a damaged blade instead of replacing it to save money, however, reconstructing its virtual model, commonly the first step in the repairing process, can be challenging due to the geometrical complexity of the blades, variability in deformations and the requirement to meet the dimensions specified by the manufacturer. This paper presents the reconstruction methodology of the clean virtual model of a steam turbine blade through numerical tools, as a previous step for regenerating a worn blade. First, few cross-sectional airfoil profiles are extracted from the damaged blade and are regenerated using Bernstein polynomials; then, using the previously obtained data, many more profiles are interpolated and stacked along the spanwise direction of the blade via Transfinite Interpolation in order to obtain a smooth and continuous representation of the reference blade. Final deviation between the reference and reconstructed model resulted in an average value of 1.5496 × 10−3 % and 9.685 × 10−5 % relative to the rotor diameter in the pressure and suction sides respectively, showing an accuracy that could be considered to be used in industrial applications or optimization.