Compressor turbine disk crack

A turbine disc has to rotate at high speed in a relatively cool environment and is subjected to large rotational stresses. Fracture analysis of turbine disks and computational. What is the equation for the energy balance between turbine, compressor and propeller. Ashutosh vengurlekar exxonmobil research and engineering, singapore mr. Static fracture and modal analysis simulation of a gas. Strain gauges were essential to the discovery and also explained the other crack pattern was due to loss of aerodynamic damping causing flutter of the 2diameter mode when in compressor. Disk requirement 2nd stage power turbine disk rh engine 2 name. The geometry of a first stage gas turbine compressor blade is obtained from us patent us 7,520,729 b2 and is used for both the single blade analysis and the bladed disk analysis. The role of the turbine blisk in a gas turbine is to expand the hot gases.

Turbine a turbine is a device that uses shaft work to drive an electric generator. This article will offer an explanation of minor resonance of disks, bettertermed interaction resonance, and end with a suggestion to be cautious of a special aspect of turbine blading resonance analysis. Pdf static fracture and modal analysis simulation of a gas turbine. It consists of a single part, instead of an assembly of a disk and individual, removable blades. Elliott compressors for worldscale ethylene plants. Corrosion pitting of an igt compressor disc top and fluorescent particle indication of a crack at blade attachment dovetail bottom cracking at the inlet air feed slot of a frame fa turbine is shown in figure 4. Its energy demand and potential plant run length, linked to its volumetric flow, molecular weight, pressure ratio and associated contaminant removal, is a major design element within the entire ethylene unit. In a gas turbine, the ambient air enters the compressor and passes through the. Lets look around inside the compressors of a few different turbine engines. Probabilistic sensitivities for fatigue analysis of. Sep 21, 2019 scc is most commonly seen on steam turbine disk blade root attachments. Compressor disk is fabricated by titanium alloy and surface crack occurs between the disk and blade attachment. Testing of discs of turbine rotors of gas compressors with. Crackgrowth simulations were performed by means of a pure fem and a combined femdbem approach for a compressor disc of a gas turbine engine.

In a free turbine the turbine driving the compressor rotates independently of that which powers the propellor or helicopter rotor. The challenges in life prediction for gas turbine components arise due to their. In the past, turbine discs have been made in ferritic and austenitic steels but. Remaining turbine section parts are available incliding one row 2 turbine disc which was crack free. This leads to a safety procedure whereby aircraft engine turbine discs are being retired at a time when one in discs has initiated a short fatigue crack of 0.

Probabilistic analysis of aircraft gas turbine disk life and reliability. Cgc is a five stages centrifugal compressor caustic wash and drying are facilitated between 4th and 5th stage 5th stage is a heat pump for dec3 system where c4 and heavier are removed cgc is driven by a shp steam turbine turbine extracts hp steam while condensing is controlled by cgc power demand. The blades should be examined for tip rub, erosion, impact damage, coating loss, cracks, and shift. Turbines can be found in steam, gas, and hydrostatic power plants. The cracked gas compressor cgc is still the most critical unit in the entire ethylene production facility. For the disc geometry studied by meguid, crack propagation took place across. Brook park, ohio 44142 abstract two series of lowcyclefatigue lcf test data for two different groups of. Investigation of candidate features for crack detection in. An integral part of rfc is the determination of crack initiation and propagation times. Antoniou airframes and engines division aeronautical and maritime research laboratory dstotr0915 abstract amrl has been developing expertise in finite element analysis fea of engine components, particularly compressor and turbine discs. Blisks may be additive manufactured, integrally cast, machined from a solid piece of material, or made by welding individual blades to a rotor disk. It was shown that a crack was initiated from the disk edge on its interface with the rotor shaft and was propagated under.

Failure analysis of a gas turbine compressor in a thermal power plant. In this work, the fatigue crackgrowth process in a rotating disk of an aircraft gas turbine engine has been simulated. Gas turbine compressor blades are an integral component to a gas. Probabilistic analysis of aircraft gas turbine disk life and reliability matthew e. The experimental results showed no metallurgical and mechanical defects for the blade materials.

Examples of such cases are ge frame 7ea compressor disc cracking, frame 7fa9fa turbine disc airfeed slot and. Surface crack modelling in an engine compressor disc. This wind turbine driven air compressor is part of a display at the science museum of minnesota. Probabilistic sensitivities for fatigue analysis of turbine. The aim of this study is to investigate low cycle fatigue crack propagation in a dovetailtype disk and blade attachment in a representative gte turbine compressor disk, with particular emphasis on the effect of the temperature in a rotating disk. Testing of discs of turbine rotors of gas compressors with the dye penetrant nondestructive testing technique article in russian journal of nondestructive testing 448. Compressors, gas turbines, pumps, steam turbines rotating disk vibration interaction resonance. Functions of compressor section of the aircraft gas turbine engine. Every wheel is subjected to xray testing and crack examination. What is a split compressor system in a turbine engine. Preliminary finite element analysis of a compressor disk in the tf30 engine j.

In the modal analysis study, increasing the depth of the crack leads. Turbine and compressor thermodynamics for engineer. Compressor blade vibrations in a gas turbine engine are an important. All turbine engines have a compressor to increase the pressure of the incoming air before it enters the combustor. What is the difference between a turbine and a compressor. All of the turbines wheels are manufactured using the vacuum investment casting process. Probabilistic analysis of aircraft gas turbine disk life and. Causes and resolution of stress corrosion cracking in. May 05, 2015 most modern passenger and military aircraft are powered by gas turbine engines, also called jet engines. A as the design of the turbomachinary components such as compressor discs, turbine blades, combustion chamber and shafts are complex and efficiency of these components are directly related to the material performance, therefore material selection is of prime. Crack detection, when dealing with the turbine disk and blades, is mostly visual, although structural inspection techniques can be used, such as penetrant methods and others to aid in the inspection. Methods of to maintaining turbine discs prone to cracks in bucket attachment dovetails are disclosed.

Crack growth life assessment on turbine component under. This enables us to assure that casting flaws such as sink holes, inclusions and cracks are avoided. The fourth stage low pressure compressor lpc disc of the tf30 engine in the flll aircraft was chosen as the first. During the expansion work will be done by the fluid to drive, for example, electric generation. Model fuel shp kws btuhphrkjkwhr lbs kgs deg f deg c. Mistuning in bladed disks due to the presence of a crack or multiple cracks in blades can cause vibration localization about a few blades 8. Us8240042b2 methods of maintaining turbine discs to avert. Probabilistic analysis of aircraft gas turbine disk life. Fatigue crack growth in a compressor stage of a turbofan engine by. All elliott compressors and turbines are thoroughly tested before shipment. Material performance in compressor discs and turbine blades. Robert d fisher exxonmobil research and engineering, houston global technology sponsor machinery mr.

Yuki nakamura mitsubishi heavy industries compressor corporation, hiroshima japan mr. Crack gas, propylene and ethylene compressor trains from elliott are custom engineered to meet the high volume, high efficiency requirements of todays. Principal differences between the two types of impellers are size and ducting arrangement. The vibration response was measured using externally. Measure the compressor turbine disk and blade assembly tip clearance. Fea is used for the analysis and prevention of operation failures of a compressor disk. Several premature failures occurred in the highpressure section of the compressor due to the fracture of the blade roots. This attachment of a dovetail type has the 26 broach angle at the axis of rotation. Turbine rotor disk health monitoring assessment based on. High frequency fatigue crack propagation behavior of a nickelbase turbine disk alloy s. Sep 28, 2015 a gas turbine is an internal combustion engine that converts heat energy of the fuel into mechanical energy via three main elements a compressor, combustor and turbine. Relative creep capability of titanium al loys used for compressor parts in the form of a larson miller plot schematic. This analysis resulted from an investigation of a compressor disk from a gas turbine engine that contained cracks in one of the 40 blade attachment.

Failure analysis of a gas turbine compressor in a thermal. The low alloy steels of steam turbine rotors are susceptible to scc in the presence of hydroxides such as naoh. Resolving one of the more serious issues, that of stress corrosion cracking, can often be achieved in a straightforward manner by accurately identifying the causes. Compressor blading materials for land based gas tur bines special steels until recently, all production blades for compressors are made from 12% chromium. Slater z wright state university, dayton, oh 45435 identi cation of fatigue cracks in turbomachinery components is a vital but costly e ort. The subject of the display is storing wind energy by. In the past, turbine discs have been made in ferritic and austenitic steels but nickelbased alloys are currently used. Variance estimates and confidence bounds of the sensitivity estimates are developed. Crackdetection experiments on simulated turbine engine. What is the typical way the compressor and turbine disks connected to lphp shaft. A comparison was made using either 20node isoparametric elements throughout the mesh or with 3d prismatic quarterpoint isoparametric elements just in the crack area.

The central region of the disk is counterbored on both sides to create the rim, web, and bore regions of a. Even with the best maintenance procedures and preventative maintenance techniques, problems can still arise. The experimental work in this study considered a conceptual design of a disk with machined teeth to imitate compressor or turbine blades and provide a cost effective test article to simulate crack initiation and propagation. Aircraft gas turbine engine compressor section aircraft.

Preliminary finite element analysis of a compressor disk. One means is to bleed cooling air back onto the face of the disk. Integrated approach to gas turbine rotor condition assessment and life management. The subsequent effort to understand the origin of this crack led to a series of analyses that included computing the stresses on the attachment, characterization of fatigue crack growth, and a model for fretting fatigue crack growth. The small duct assembly is disassembled to inspect the compressor turbine stator as well as the small duct. Gas turbine diskblade attachment crack springerlink. Pratt whitney turbine disk engine 30293 270 threshold 84342 last or completed 31423 at inst. Combustion section inspection part two flight mechanic. The path to improved cracked gas compressor performance. Sh3072 7282015 remaining due pratt whitney life limit. May 01, 2016 this leads to a safety procedure whereby aircraft engine turbine discs are being retired at a time when one in discs has initiated a short fatigue crack of 0. My question is, what exactly is this sort of design feature used for in a compressor or turbine disc. Failure analysis and repair of a catastrophically damaged gas. Failure analysis of ti6al4v gas turbine compressor blades.

The pri mary objective of the program was to make an analytical study of a novel approach in structural disk design which would improve the life of the. In this study, the fatigue crack growth and lifetime prediction of aviation gas turbine engine compressor disks under operating conditions are analyzed. Static fracture and modal analysis simulation of a gas turbine. There are several different types of gas turbine engines, but all turbine engines have some parts in common.

Lcf test data for two different groups of aircraft gas turbine engine compressor disk geometries were reanalyzed and compared by using weibull statistics. These elements were brought together to simulate the conditions that led to the. In a gas turbine, the ambient air enters the compressor. The tf41a1b engine is an axial flow gas turbine engine with a round fixedgeometry inlet, fivestage, lowpressure compressor, including a threestage low. According to table 1, the crack on the free surface of the compressor disk increased in size from 0. The two principal types of compressors use in gas turbine aircraft engines are centrifugal flow and axial flow. In the modal analysis study, increasing the depth of the crack leads to a decrease. From my understanding, the great majority of loads imposed upon a compressor or turbine disc will be centrifugal radial loads, which will tend to try and expand the disc radially. We take a detailed look at how a compressor rotor is held together in large jet engine. This kind of rotors i also used in my homemade jet engine. The limiting factor that affects the useful disc life is its resistance to fatigue cracking. Prediction of crack growth from bolt holes in a disc. Conventional life assessment methods of bladedisc connections of gas turbines are almost based on finite element analysis 5 and the experimental data of.

Based on the normal service operation of the compressor, the centrifugal and shear forces applied to the bladedisc configuration were considered in the model. An improved turbine disk design to increase reliability of aircraft jet engines nasacr5033 an inproved turbine disk n7626201 disk substantially improved the life of the disk. Cracks on the disk necessitate the rejection of the disk and replacement of the turbine rotor. One of the latest damages to a gas turbine due to failure of its compressor disk was reported in a 32 mw gas turbine in rei electrical power plant. In all of these failures, crack propagation started from a partthrough surface crack defect. Ge aeroderivative gas turbines design and operating features ge power systems ger3695e 2 ge industrial aeroderivative gas turbine performance characteristics mechanical drive gas turbine ratings output heat rate exhaust flow exhaust temp. Integrated approach to gas turbine rotor condition. Since this valuable turbo machinery doesnt have a backup, it must run reliably for two to seven years so operators can efficiently and safely m aximize production to meet market demands. High frequency fatigue crack propagation behavior of a. Keywords gas turbine compressor disk failure crack fretting fatigue introduction gas turbines are complex systems of producing power, a large number of which are utilized in the power plants with the aim to generate electric power. Steam turbines are used across the world as a source of power for many different industries. Aexplain what material properties are relevant to reliable material performance in compressor discs and turbine blades. Evaluation of a gas turbine disk revealed a crack in the blade attachment area. Mesh for crack propagation analysis in the bolt hole of a compressor disc.

Zaretsky national aeronautics and space administration glenn research center cleveland, ohio 445 and richard august nyma, inc. Failure characterisation of ti6al4v gas turbine compressor blades. The split compressor system requires two concentric shafts joining the turbine stages to their respective compressors. The methodology is demonstrated and verified using a multizone probabilistic fatigue analysis of a gas turbine compressor disk analysis considering stress scatter, crack growth propagation scatter, and initial crack size as random variables. As gas turbines operate in a continuous thermodynamic cycle, they have a higher power density than other types of internal combustion engines.

Investigation of candidate features for crack detection in fan and turbine blades and disks michelle meier, oleg v. High frequency fatigue crack propagation behavior of a nickel. Crack growth rate and lifetime prediction for aviation gas. There are three basic categories of gas turbine engine compressor. Failure analysis and repair of a catastrophically damaged. The turbine disks to which the blades are attached are subject to much higher. In one embodiment, wherein a turbine disc comprises a plurality of bucket attachment dovetail regions, one or more of the bucket attachment dovetail regions comprises a cooling slot, and each cooling slot comprises edges and adjacent surfaces, a method comprises inspecting the one or more of. A cncmilled, single piece axial compressor blisk a blisk portmanteau of bladed disk is a turbomachine component comprising both rotor disk and blades. The purpose of this program was to provide an improved turbine disk design which would increase the reliability of aircraft engines. Failure characterisation of ti6al4v gas turbine compressor. The engine drive shafts, compressor discs, turbine discs, and gear trains are.

Milligan a, a department of metallurgical and materials engineering, michigan technological university, houghton, mi 49931, usa. The present study deals with the fatigue analysis of a turbine disc integrated blade and disc for a small gas turbine for a short life application. Damage accumulation of a turbine blade is subjected to static load. Initiation of cracks in compressor disks made from twophase titanium alloy has occurred in a disk and blade attachment fig. Turbine blades are usually inspected and cleaned in the same manner as compressor blades. A blisk portmanteau of bladed disk is a turbomachine component comprising both rotor disk and blades. Vibration and crack detection in gas turbine engine compressor. The life to crack initiation was increased from 30,000 cycles to more than 100,000 cycles the cycles to. Abstractthe gas turbine is the heart of all modern marine propulsion. A hcf crack that causes a blade to break off of the disk can damage. How does it all fit together, where does the air go, and how does it work. Us8240042b2 methods of maintaining turbine discs to. As the name suggests, gas turbine engine compressors provide the compression part of the gas turbine engine thermodynamic cycle. Jun 19, 20 here you see how to make a compressorturbine blade.

Nozzaloy not only shows the highest resistance to crack initiation, but the crack propagation rate is also as low as the base metal. Macro and microfractographic investigations were carried out on the fracture surfaces. A blisk is a turbo machine component comprising both rotor disk and blades. Cooling air, bled from the compressor, may be used to cool the turbine blades, vanes and discs to allow higher turbine entry gas temperatures for the same turbine material temperatures. The crackdetection methodology that was recently investigated on the high precision spin rig involved introducing a notch on a simulated turbine engine disk and monitoring its vibration response as the disk was rotated at speeds up to 12 000 rpm. Apr 06, 2012 lets look around inside the compressors of a few different turbine engines. Material performance in compressor discs and turbine. Failure analysis of a gas turbine compressor sciencedirect. Slight pitting caused by the impingement of foreign matter may be blended by stoning and polishing. Turbine blades are susceptible to damage and crack formation in regions of component contact that experience both centrifugal and oscillatory vibrations garcia and grandt, 2005.

The 191 rotor with the 3 cracked discs has had the turbine section removed to be able to use on of the good disc. Tips for keeping this workhorse in top flight condition. The bladed disk consists of 20 identical equally spaced compressor blades mounted on a disk of outer diameter of 700 mm and inner diameter of 530 mm. Turbine engine fan disk crack detection test william j. Solutions of the sifs under operating loading conditions of the compressor disk are then implemented into the proposed crack propagation model. The ct disk and small exit duct as well as the large exit duct are removed. Journal of engineering for sustainable buildings and cities.

Mesh for crack propagation analysis in the bolt hole of a compressor. Crack detection, when dealing with the turbine disk and blades, is mostly visual. Preliminary finite element analysis of a compressor disk in. Crack growth rate and lifetime prediction for aviation gas turbine.