scholarly journals Advances in Gas Turbine Blade Repair by Laser Welding

1997 ◽  
Author(s):  
Ettore Gandini ◽  
Franco Agnesone ◽  
Federica Taricco ◽  
Leonardo Arrighi
Keyword(s):  
Laser Welding ◽  
Gas Turbine ◽  
Filler Metal ◽  
Stress Rupture ◽  
Microstructural Characterization ◽  
Operating Life ◽  
Blade Alloy ◽  
Machining Operations ◽  
Industrial Gas Turbine ◽  
Blade Repair

Industrial gas turbine components are subject, in the course of their operating life, to various kinds of damages, requiring repair processes during periodical overhauling operations. Blades, in particular, suffer from creep, corrosion, wear phenomena. The majority of blade damage is currently repaired by means of manual TIG welding, with a filler metal which is often different from the blade alloy. This leads to an inferior metallurgical and mechanical condition of the repaired area as compared to the base metal. Besides, the nickel superalloys of the blades are often subject to cracking during welding operations. A process of laser welding for the repair of the airfoil tip has been introduced and optimized, to improve the characteristics of the repaired component. Powder of the same alloy of the part is used as filler metal, and the process is carried out using a Nd:YAG laser, equipped with a 6–axis CNC motion control. The original blade geometry is rebuilt by multi–layer cladding, then the blade is submitted to machining operations, NDT testing and heat treatment. The optimizing activity has been performed with the aid of microstructural characterization, chemical composition checking (by EDX microanalysis), hardness and stress rupture testing of the welded specimens.

scholarly journals Metallurgical Development for Added Reliability of Industrial Gas Turbine Rotating Blades

1968 ◽  
Author(s):  
F. J. Wall
Keyword(s):  
Gas Turbine ◽  
Stress Rupture ◽  
Rotating Blades ◽  
Time Stress ◽  
Corrosion Evaluation ◽  
Long Time ◽  
Industrial Gas Turbine ◽  
Microstructural Studies ◽  
Selection Of

Increased reliability of industrial gas turbine rotating blades in the hot section of turbines has been achieved by utilization of advanced metallurgical techniques. These techniques include vacuum melting master alloy heats, minimizing residual stresses in blades after machining, and increasing the quality of nondestructive inspection of blades during and after fabrication. In addition, long time stress-rupture tests, corrosion evaluation, and microstructural studies on advanced alloys have provided necessary information for selection of turbine blade alloys for future generations of turbines.

Application of Design-for-LCA Methodology to Compare Architectural Alternatives for the Compressor Rotor of an Industrial Gas Turbine

2019 ◽  
Author(s):  
Alessandro Musacchio ◽  
Mattia Vicarelli ◽  
Simone Colantoni ◽  
Pietro Bartocci ◽  
Francesco Fantozzi
Keyword(s):  
Environmental Impact ◽  
Gas Turbine ◽  
Material Selection ◽  
Key Factors ◽  
Preliminary Assessment ◽  
Operating Life ◽  
Compressor Rotor ◽  
Traditional Design ◽  
Design Alternatives ◽  
Industrial Gas Turbine

Abstract Nowadays a preliminary assessment on environmental impact of a new product is becoming more and more important. It is useful for a designer to access to a comprehensive methodology that supports configuration assessments taking into account the whole product lifecycle from the beginning of conceptual phase. To develop a competitive product, and particularly a gas turbine, each design trade-off needs to be performed considering not only the typical parameters such as performances, life and costs but also the cradle-to-grave environmental impact. Scope of the following paper is the application of design-for-Environment methodology to different architectures of GT compressor rotor module. Three design alternatives are analyzed and compared in terms of ELCA considering their design, material selection, manufacturing process and operating life. Specific considerations are proposed as a result of the combination of traditional design practices with environmental assessment. This study highlighted that number of parts, weight and amount of material removed or scraped that is, in other words, the level of production process optimization, are the key factors to control the environmental impact of a product.

scholarly journals An Investigation on Failure Analysis of Titanium Gas Turbine Compressor Blades

2007 ◽  
Vol 561-565 ◽  
pp. 2241-2244
Author(s):  
H. Sepehri Amin ◽  
Ahmad Kermanpur ◽  
Saeed Ziaei-Rad ◽  
Hassan Farhangi ◽  
M. Mosaddeghfar
Keyword(s):  
Gas Turbine ◽  
Failure Process ◽  
Compressor Blades ◽  
Blade Root ◽  
Debris Particles ◽  
Blade Alloy ◽  
Beach Marks ◽  
Gas Turbine Compressor ◽  
Industrial Gas Turbine ◽  
Experimental Characterisation

Several premature failures were occurred in the high-pressure section of an industrial gas turbine compressor due to the fracture of Titanium blade roots. In this work, the failure process of the compressor blades was investigated based on the experimental characterisation. Macro/microfractographic studies were carried out on the fracture surfaces. Optical and scanning electron microscopy of the blade airfoil and root were performed. Mechanical properties of the blade alloy were also evaluated and compared with the standard specifications. The experimental results showed no metallurgical and mechanical defects for the blade materials. Microstructures of the blade root and airfoil as well as the hardness and tensile properties were all comparable with those reported in the standard specification AMS 4928Q. Fractography experiments showed clearly multiple crack initiation sites and fatigue beach marks. Debris particles were observed on the fracture surface of samples and in the mouth of initiated cracks. The blade surface in contact to the disc in the dovetail region showed a higher surface roughness than the other surfaces. Based on the results obtained, the fretting fatigue mechanism was proposed for the premature failures. It was concluded that the stress concentration has been caused by either unsuitable curvature ratio of the disk dovetail, incorrect design of the blade or insufficient distance between the blade root and the disk in dovetail region.

Development of L1-norm sliding mode observer for sensor fault diagnosis of an industrial gas turbine

2021 ◽  
pp. 095965182199617
Author(s):  
Mahyar Akbari ◽  
Abdol Majid Khoshnood ◽  
Saied Irani
Keyword(s):  
Fault Detection ◽  
State Space ◽  
Gas Turbine ◽  
Sliding Mode ◽  
State Space Model ◽  
Sensor Fault ◽  
Space Model ◽  
Decision Logic ◽  
Sensor Fault Detection ◽  
Industrial Gas Turbine

In this article, a novel approach for model-based sensor fault detection and estimation of gas turbine is presented. The proposed method includes driving a state-space model of gas turbine, designing a novel L1-norm Lyapunov-based observer, and a decision logic which is based on bank of observers. The novel observer is designed using multiple Lyapunov functions based on L1-norm, reducing the estimation noise while increasing the accuracy. The L1-norm observer is similar to sliding mode observer in switching time. The proposed observer also acts as a low-pass filter, subsequently reducing estimation chattering. Since a bank of observers is required in model-based sensor fault detection, a bank of L1-norm observers is designed in this article. Corresponding to the use of the bank of observers, a two-step fault detection decision logic is developed. Furthermore, the proposed state-space model is a hybrid data-driven model which is divided into two models for steady-state and transient conditions, according to the nature of the gas turbine. The model is developed by applying a subspace algorithm to the real field data of SGT-600 (an industrial gas turbine). The proposed model was validated by applying to two other similar gas turbines with different ambient and operational conditions. The results of the proposed approach implementation demonstrate precise gas turbine sensor fault detection and estimation.

scholarly journals Properties of a thick-section narrow-gap gas tungsten arc weld of cast Haynes 282

2021 ◽  
Author(s):  
Michael Santella ◽  
X. Frank Chen ◽  
Philip Maziasz ◽  
Jason Rausch ◽  
Jonathan Salkin
Keyword(s):  
Base Metal ◽  
Heat Affected Zone ◽  
Reference Data ◽  
Filler Metal ◽  
Stress Rupture ◽  
Narrow Gap ◽  
Weld Deposit ◽  
Gas Tungsten Arc ◽  
Gas Tungsten ◽  
Weld Heat

AbstractA 50.8-mm-deep gas tungsten arc weld was made with matching filler metal in cast Haynes 282 alloy. The narrow-gap joint was filled with 104 weld beads. Visual and dye-penetrant inspection of cross-weld specimens indicated that the cast base metal contained numerous casting defects. No visible indications of physical defects were found in the weld deposit. The weld heat-affected zone was characterized by microcracking and localized recrystallization. The cause of the cracking could not be determined. Hardness testing showed that a softened region in the as-welded heat-affected zone was nearly eliminated by post-weld heat treatment. Tensile testing up to 816 °C showed that cross-weld specimen strengths ranged from 57 to 79% of the cast base metal tensile strength. The stress-rupture strengths of cross-weld specimens are within 20% of base metal reference data. Failures of both tensile and stress-rupture specimens occurred in the base metal.

Performance Prediction of Gas Turbine Under Different Strategies Using Low Heating Value Fuel

2013 ◽  
Author(s):  
Edson Batista da Silva ◽  
Marcelo Assato ◽  
Rosiane Cristina de Lima
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Equivalence Ratio ◽  
Safe Operation ◽  
Engine Operation ◽  
Heating Value ◽  
Gasification Process ◽  
Surge Margin ◽  
And Performance ◽  
Industrial Gas Turbine

Usually, the turbogenerators are designed to fire a specific fuel, depending on the project of these engines may be allowed the operation with other kinds of fuel compositions. However, it is necessary a careful evaluation of the operational behavior and performance of them due to conversion, for example, from natural gas to different low heating value fuels. Thus, this work describes strategies used to simulate the performance of a single shaft industrial gas turbine designed to operate with natural gas when firing low heating value fuel, such as biomass fuel from gasification process or blast furnace gas (BFG). Air bled from the compressor and variable compressor geometry have been used as key strategies by this paper. Off-design performance simulations at a variety of ambient temperature conditions are described. It was observed the necessity for recovering the surge margin; both techniques showed good solutions to achieve the same level of safe operation in relation to the original engine. Finally, a flammability limit analysis in terms of the equivalence ratio was done. This analysis has the objective of verifying if the combustor will operate using the low heating value fuel. For the most engine operation cases investigated, the values were inside from minimum and maximum equivalence ratio range.

Electrical studies for an industrial gas turbine cogeneration facility

1989 ◽  
Vol 25 (4) ◽  
pp. 750-765 ◽  
Author(s):  
R.L. Doughty ◽  
L. Gise ◽  
E.W. Kalkstein ◽  
R.D. Willoughby
Keyword(s):  
Gas Turbine ◽  
Electrical Studies ◽  
Industrial Gas Turbine
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