Failure analysis of the final stage blade in steam turbine. Structural and thermal analysis of steam turbine blade using fem ruttala bhargav m. Blade failure is a common problem of a steam turbine and its failure inservice results in safety risky, repair cost and operational revenue losses. Blade material the material used for the turbine blades is based on the level of turbine operation.
Recent trends in repair and refurbishing of steam turbine. Dynamic analysis of a ste am turbine blade in computational environment is carried. Several different analyses were carried out in order to identify the failures root cause. The blades are made of x20cr tempered martensitic stainless steel material. The observed fracture mechanism was traced back to. Wed like to understand how you use our websites in order to improve them. Design and analysis of steam turbine blades iopscience. This paper presents details of observations, inspections carried out and root cause analysis of the turbine blade failure. The blade failure was detected early by company vibration analyst in july 2006, when maximum shaft vibration had a step change from 9 microns to 18 microns pkpk. The first stage rotor blade of the steam turbine has. Request pdf steam turbine blade failure analysis a last stage turbine blades failure was experienced in two units of 660mw. The paper addresses the key elements that could have possibly lead to the failure of the turbine blade and highlights the importance of scrutinizing. Metallurgical failure analysis of cracked turbine blades. The field inspection revealed that one of last stage blades and the damping wire were broken.
These units have one highpressure turbine and two tandemcompound. A last stage turbine blades failure was experienced in two units of 660 mw. Thus, the reliability of these blades is very important for the successful operation of a steam turbine. The failure of a turbine blade of a 60 mw thermal power plant is addressed in this paper.
In a 110 mw unit of a fossil fuel power plant operated in western part of india, low pressure turbine 3a stage blades failed prematurely. These units have one highpressure turbine and two tandemcompound lowpressure turbines with 44in last stage blades. The blades are responsible for extracting energy from the high temperature, high pressure gas produced by the combustor. Low cycle fatigue analysis of a last stage steam turbine blade. Metal magnetic memory mmm method, based on the magnetoelasticity and mechanical effect theory, is a new nondestructive testing technology. Thus, the better the design of the blade, the more efficient the turbine will be. Design, stress analysis of l ow pressure steam turbine blade. It has been found that the mmm signal variation gradient of the. After containing the temperature distribution, the rotor blade was then analyzed for the combined mechanical and thermal stresses and also the fatigue life. Pdf failure analysis of the 350 mw steam turbine blade root. Make an unbalance response analysis of a blade in order to calculate blade deformation and quantify the forces acting.
Through optimal application of technology and proven expertise, stork turbo blading is unmatched in its ability to produce the blades in. The blades that failed were in a low pressure lp turbine connected to the high pressure turbine lp1 and in lp turbine connected to the generator. Paper open access design and analysis of steam turbine. A large hammering noise existed prior to the failure. Failure analysis of a compressor blade of gas turbine engine swati biswas, md ganeshachar, jivan kumar and vn satish kumar materials application group, gas turbine research establishment, bangalore560093, india email id. The turbine blades are often the limiting component of gas turbines.
Steam turbine blade mmm testing and failure analysis. Failure analysis to blades of steam turbines at normal conditions. During the maintenance of a steam turbine, several l2. Root cause analysis of steam turbine blade failure springerlink. The failure blade and its fracture face are tested with mmm technology at workshop. The subject turbine was one of the new steam turbine compressor drivers added at this time. This paper presents an analysis of the cause of fracture in a steam turbine blade root. In this work a visual inspection was combined with a revision of the turbine operation history.
The fatigue crack had initiated at the leading edge and propagated progressively over about 80% of the blade cross section before giving rise to final overload failure. George m lucas a concise reference for practicing engineers involved in the design, specification, and evaluation of industrial steam turbines, particularly critical process compressor drivers. Failure investigation was carried out using various techniques such as visual examination, stereo. The laststage blades failure evaluation was carried out. Proper analysis of the failure should be carried out before attempting a repair. The fracture appeared 5 inches from the blade root platform, fig.
Theory of creep creep behaviour of a metal is determined by measuring the strain. Blade failure in a steam turbine is a prevalent occurrence and has a strong correlation with the forces acting on the blade, which are centrifugal forces, centrifugal bending, steady steam bending. In a number of cases, the structural degradation results in a significant change in the. Failure analysis of a steam turbine rotor, engineering. Structural and thermal analysis of steam turbine blade using fem. Latest technologies and future prospects for a new steam turbine. Both trends have increased the risk of failure for forced response due to the occurrence of resonance or to the decrease of alternating stress margins. Failure analysis of the 350 mw steam turbine blade root article pdf available in engineering failure analysis 164. The paper addresses the key elements that could have possibly lead to the failure of the turbine blade and highlights the importance of. What is steam turbine description and characteristics.
There are some signs of foreign objects damage fod on top of. A turbine flow analysis was realized together with verification of the blade root dimensions and tolerances. Each l0 row consists of 180 blades in 45 groups of 4, with the 4blades in each group connected by three tiewires. Subjects will include high temperature corrosion on hot gas expander blades and stress corrosion cracking of steam turbine disks and compressor impellers. Failure analysis of gas turbine blades semantic scholar. Pdf this paper presents an analysis of the cause of fracture in a steam turbine blade root. In this work, the last stage l1 blades of a steam turbine under cyclic load or fatigue were analyzed, the first instance. Analysis of steam turbine blade failure causes request pdf. The main cause of failure of lp steam turbine blade is high cycle fatigue 6. This failure analysis case study of cracked turbine blades is presented in a condensed version of mais client report format. The blade was made of 174 ph stainless steel and has been used for 12 years before failure.
Paper open access design and analysis of steam turbine blades. Make an unbalance response analysis of a blade in order to calculate blade deformation and quantify the. The level of design is one of the most important factors restricting the performance of steam turbines, which is related to the working efficiency of the steam turbine. The need to provide quality services, accurate diagnosis, timely rehabilitation and improvement in materials and operation of the turbines, have given way to scientific research crack initiation and crack propagation, the impending fracture and estimating life of the turbine components at normal conditions and resonance. Steam turbine root failure cause analysis flowchart. The investigation included a metallographic analysis of the cracked blades, natural frequency test and analysis, blade stress analysis, units operation parameters and history of events analysis, fracture mechanics and crack propagation analysis. Root cause analysis of steam turbine blade failure. Failure analysis of a compressor blade of gas turbine engine. During the maintenance of a steam turbine, several l2 blade roots with crack were encountered.
These units have one highpressure turbine and two tandemcompound lowpressure turbines with 44in. A specific focus on blade profile, material used in the production of steam turbine blades, and the factors that cause turbine blade failure and therefore the failure of the turbine itself. Longterm gas turbine operation leads to the structural degradation of superalloy blades there is a change in a number, shape and size of. Failure analysis to blades of steam turbines at normal. Failure analysis of a lowpressure turbine blade in a coal. They have found that the blade failure took place by dissolving the. Lprimlife combines the necessary stress analysis and fracture mechanics algorithms with applicable material degradation data to estimate remaining life. Failure analysis of rotating blades of lowpressure steam turbine. Steam turbine blade failure analysis request pdf researchgate. Most of the damages are on the tip of the leading edge and also, bulk separation is obvious in this region. Case study lifetime extension of steam turbine after blade. The findings of this study, based on the operating conditions and the characteristics of failed turbine blade, suggest a corrosion fatiguerelated failure. A turbine blade is the individual component which makes up the turbine section of a gas turbine or steam turbine.
In general, a steam turbine is a rotary heat engine that converts thermal energy contained in the steam to mechanical energy or to electrical energy. Blade design and analysis for steam turbines ebook, 2011. Blade failure was observed on a backpressure steam turbine driving a centrifugal compressor after it was in service for more than one year. The failure of the first stage blade in a steam turbine of 55 mw was investigated. Latest technologies and future prospects for a new steam. Unlike with reciprocating engines, for instance, compression, heating and expansion are.
A common failure mode for turbine machine is high cycle of fatigue of compressor and turbine blades due to high dynamic stress caused by blade vibration and resonance within the operating range of. Structural and thermal analysis of steam turbine blade. Forced response analysis of a steam turbine shrouded blade. To survive in this difficult environment, turbine blades often use exotic materials like. With the wide application of turbomachinery and the continuous advancement of design technology, steam turbine blade design technology has become an important research field. After about three months of operation, the first failure on valve no. This paper deals with the fatigue analysis of a low pressure blade that is used for the last stages of large steam turbines.
Blade failure is a common problem of a steam turbine and its failure inservice results in safety risks, repair cost and non operational revenue losses. Request pdf failure analysis of the final stage blade in steam turbine a failure case of the low pressure blades of steam turbine is presented in this paper. Failure might have occurred because of faults in design, fabrication or manufacturing, wrong selection of material or operational mistakes. Piraccini, francesco, lorusso, salvatore, maceli, nicola, and ryman, john. Steam turbine blade failure analysis sciencedirect. Pdf steam turbine blade failure analysis rafael garcia. Failure analysis of the 350 mw steam turbine blade root. Failure analysis to blades of steam turbines at normal conditions of operations and resonance.
Failure analysis of a steam turbine rotor failure analysis of a steam turbine rotor barella, s bellogini, m boniardi, m cincera, s. Since they failed prematurely, root cause analysis was sought. Once established, the tcat and the formal program will have representatives from, and continued interfaces with, plant operating, maintenance, chemistry, and engineering personnel. Pdf steam turbine blade failure analysis rafael garcia illescas.
Failure analysis of rotating blades of low pressure steam turbine rotors and possibility of prediction corrosionfatigue ruptures. Each l0 row consists of 180 blades in 45 groups of 4, with the 4. In its simplest form, a steam turbine consist of a boiler steam generator, turbine, condenser, feed pump and a variety of auxiliary devices. Dynamic analysis of a steam turbine blade in computational environment is carried. The l1 stage blades suffer high alternating stresses, for its size. This paper aims at the material property and failure analysis for steam turbine blade with mmm method. This project enumerates design of airfoil shape of steam turbine blade, stresses due to thermal and dynamic loads of low pressure steam turbine blade of. The main objective of the paper is to present an analysis that leads to detect the most possible cause of the l0 blade fracture. Failure analysis of first and second stage turbine blade first stage visual observation indicates that more than 90% of the first stage blades were damaged. With over eighty years of experience we support and assist our customers with advanced engineering, production and quality expertise.
Investigation of steam turbine blade failure oaktrust. The objective of this case study is to share the failure analysis of a steam turbine blades due to blade excitation aided by corrosion. The company awarded sulzer a contract to perform the complete inspection and repair. Failure investigation was carried out using various techniques such as visual examination, stereo microscopy. Mw unit of a fossil fuel power plant operated in western part of india, low pressure turbine 3a stage blades failed prematurely. Since then turbines based on these principles have evolved in parallel and in fact merged to some degree.
1231 458 59 1437 761 942 771 1043 713 824 954 403 1162 943 90 1373 777 1250 1027 622 343 1268 1523 1246 1384 879 1453 210 1567 1430 102 279 1081 514 1111 604 573 93 187 2 900