scholarly journals ДЕМПФИРОВАНИЕ КОЛЕБАНИЙ ОХЛАЖДАЕМЫХ ПОПАРНО БАНДАЖИРОВАННЫХ РАБОЧИХ ЛОПАТОК ТУРБИН

2019 ◽  
pp. 109-113
Author(s):  
Руслан Юрьевич Шакало ◽  
Роман Петрович Придорожный ◽  
Юрий Владимирович Якушев ◽  
Вячеслав Михайлович Меркулов ◽  
Анатолий Павлович Зиньковский
Keyword(s):  
Contact Surface ◽  
Thermal Stresses ◽  
Turbine Blades ◽  
Small Sample ◽  
Dynamic Stresses ◽  
Turbine Engine ◽  
Optimal Force ◽  
Contact Surfaces ◽  
Engine Failure ◽  
Working Blades

The cooled turbine blades are the parts that determine the reliability and service life of a gas turbine engine. As is known, most cases of engine failure are related to the destruction of turbine blades. Turbine blades during operation experience high thermal stresses, the stresses from centrifugal and gas forces, as well as dynamic stresses. This paper presents methods for ensuring an acceptable level of dynamic stresses in turbine blades. One of the most effective methods is considered in more detail - pairwise shrouded cooled turbine blades. The effectiveness of the damping of such working blades depends on the guaranteed contact of the contact surfaces of the flanges of the shanks and banding shelves and the optimality of the shroud connection. As the object of the study, we chose pairwise shrouded turbine blades from the engine, on which there were several cases of destruction of the turbine blades. To assess the optimality of the bandage connection of the working blades under study, a scheme has been developed for calculating the force acting on the contact surfaces of the banding shelves. According to the developed scheme, calculations were made of the forces acting on the contact surfaces of the retaining shelves, both of the investigated working blades, and similarly pairwise shrouded cooled turbine blades, developed by SE «Ivchenko-Progress». After calculating the force acting on the contact surface of the retaining shelf, the ratio of the received force to the parameters of the feather profile, such as chord and CMAX, is calculated. According to the data obtained, a graph of the dependence of the voltage in the blade on the relative force acting on the contact surface of the retaining shelf was plotted. The analysis of the obtained graph made it possible to conclude that there is an optimal force at which dynamic stresses will be acceptable. However, since a small sample of pairwise shrouded cooled turbine blades is presented, it is necessary to continue the work on determining the criteria for optimality of the shroud linkage and on clarifying the resulting relationship.

scholarly journals Comprehensive report on Materials for Gas Turbine Engine Components

2019 ◽  
Vol 9 (2S2) ◽  
pp. 155-158
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Thermal Stresses ◽  
Prolonged Exposure ◽  
Raw Materials ◽  
Turbine Blades ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Engine Component

In the past three decades, it is very challenging for the researchers to design and development a best gas turbine engine component. Engine component has to face different operating conditions at different working environments. Nickel based superalloys are the best material to design turbine components. Inconel 718, Inconel 617, Hastelloy, Monel and Udimet are the common material used for turbine components. Directional solidification is one of the conventional casting routes followed to develop turbine blades. It is also reported that the raw materials are heat treated / age hardened to enrich the desired properties of the material implementation. Accordingly they are highly susceptible to mechanical and thermal stresses while operating. The hot section of the turbine components will experience repeated thermal stress. The halides in the combination of sulfur, chlorides and vanadate are deposited as molten salt on the surface of the turbine blade. On prolonged exposure the surface of the turbine blade starts to peel as an oxide scale. Microscopic images are the supportive results to compare the surface morphology after complete oxidation / corrosion studies. The spectroscopic results are useful to identify the elemental analysis over oxides formed. The predominant oxides observed are NiO, Cr2O3, Fe2O3 and NiCr2O4. These oxides are vulnerable on prolonged exposure and according to PB ratio the passivation are very less. In recent research, the invention on nickel based superalloys turbine blades produced through other advanced manufacturing process is also compared. A summary was made through comparing the conventional material and advanced materials performance of turbine blade material for high temperature performance.

Dynamics Characteristics for Contact Surface of Machine Tool

2014 ◽  
Vol 538 ◽  
pp. 91-94
Author(s):  
Wei Ping Luo
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Contact Surface ◽  
Dynamic Performance ◽  
Virtual Prototype ◽  
Prototype Model ◽  
Ansys Software ◽  
Dynamic Analyses ◽  
Contact Surfaces

A virtual prototype model of Machine Tool has been constructed by using the Pro/E software and the ANSYS software. Considering the effects of contact surfaces, dynamic analyses of Machine Tool are studied. The effects of contact surfaces on the dynamic characteristics of machine tool are studied. So that the purpose predicting and evaluating synthetically the machine tool dynamic performance without a physical sample can be achieved.

Effects of Downstream Vane Bowing and Asymmetry on Unsteadiness in a Transonic Turbine

2018 ◽  
Author(s):  
John P. Clark ◽  
Richard J. Anthony ◽  
Michael K. Ooten ◽  
John M. Finnegan ◽  
P. Dean Johnson ◽  
...  
Keyword(s):  
Turbine Blades ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Time Resolved ◽  
Turbine Engine ◽  
Shock Interactions ◽  
Design Changes ◽  
Post Test ◽  
Measured Time ◽  
Transonic Turbine

Accurate predictions of unsteady forcing on turbine blades are essential for the avoidance of high-cycle-fatigue issues during turbine engine development. Further, if one can demonstrate that predictions of unsteady interaction in a turbine are accurate, then it becomes possible to anticipate resonant-stress problems and mitigate them through aerodynamic design changes during the development cycle. A successful reduction in unsteady forcing for a transonic turbine with significant shock interactions due to downstream components is presented here. A pair of methods to reduce the unsteadiness was considered and rigorously analyzed using a three-dimensional, time resolved Reynolds-Averaged Navier Stokes (RANS) solver. The first method relied on the physics of shock reflections itself and involved altering the stacking of downstream components to achieve a bowed airfoil. The second method considered was circumferentially-asymmetric vane spacing which is well known to spread the unsteadiness due to vane-blade interaction over a range of frequencies. Both methods of forcing reduction were analyzed separately and predicted to reduce unsteady pressures on the blade as intended. Then, both design changes were implemented together in a transonic turbine experiment and successfully shown to manipulate the blade unsteadiness in keeping with the design-level predictions. This demonstration was accomplished through comparisons of measured time-resolved pressures on the turbine blade to others obtained in a baseline experiment that included neither asymmetric spacing nor bowing of the downstream vane. The measured data were further compared to rigorous post-test simulations of the complete turbine annulus including a bowed downstream vane of non-uniform pitch.

Numerical and Experimental Investigation for Internal Cooling of Two Pass Gas Turbine Blades Channels Using Broken V Ribs

2014 ◽  
Author(s):  
Sourabh Kumar ◽  
R. S. Amano
Keyword(s):  
Gas Turbine ◽  
Thermal Stresses ◽  
Turbine Blades ◽  
Research Work ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Square Duct

Improvements in the thermal efficiency of a gas turbine can be obtained by operating it at high inlet temperatures. This high inlet temperature develops high thermal stresses on the turbine blades in addition to improving the performance. Cooling methodologies are implemented inside the blades to withstand those high temperatures. Four different combinations of broken 60° V ribs in cooling channel are considered. The research work investigates and compares numerically and experimentally, internal cooling of channels with broken V ribs. Local heat transfer in a square duct roughened with 60° V broken ribs is investigated for three different Reynolds numbers. Aspect ratio of the channel is taken to be 1:1. The pitch of the rib is considered to be 10 times the width of the rib, which is 0.0635 m. The square cross section of the channel is 0.508 × 0.508 m2 with 0.6096 m length. This study provides information about the best configuration of a broken V rib in a cooling channel.

scholarly journals Development of Ceramic Gas Turbine Components for the CGT301 Engine

1996 ◽  
Author(s):  
Mitsuru Hattori ◽  
Tsutomu Yamamoto ◽  
Keiichiro Watanabe ◽  
Masaaki Masuda
Keyword(s):  
Gas Turbine ◽  
Technology Development ◽  
Turbine Blades ◽  
High Heat ◽  
Turbine Engine ◽  
Development Organization ◽  
All Ceramic ◽  
New Energy ◽  
Ceramic Components ◽  
Resistant Ceramic

NGK Insulators, Ltd. (NGK) has undertaken the research and development on the fabrication processes of high-heat-resistant ceramic components for the CGT301, which is a 300kW recuperative industrial ceramic gas turbine engine. This program is under the New Sunshine Project, funded by the Ministry of International Trade and Industry (MITI), and has been guided by the Agency of Industrial Science & Technology (AIST) since 1988. The New Energy and Industrial Technology Development Organization (NEDO) is the main contractor. The fabrication techniques for ceramic components, such as turbine blades, turbine nozzles, combustor liners, gas-path parts, and heat exchanger elements, for the 1,200°C engine were developed by 1993. Development for the 1,350°C engine has been underway since 1994. The baseline conditions for fabricating of all ceramic components have been established. This paper reports on the development of ceramic gas turbine components, and the improved accuracies of their shapes as well as improved reliability from the results of the interim appraisal conducted in 1994.

Crystal Visco-Plastic Model for Directionally Solidified Ni-Base Superalloys Under Monotonic and Low Cycle Fatigue

2021 ◽  
Author(s):  
Navindra Wijeyeratne ◽  
Firat Irmak ◽  
Ali P. Gordon
Keyword(s):  
Grain Boundaries ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Low Cycle Fatigue ◽  
Turbine Blades ◽  
Material Behavior ◽  
Flow Rule ◽  
Cycle Fatigue ◽  
Directionally Solidified ◽  
Crystallographic Slip

Abstract Nickel-base superalloys (NBSAs) are extensively utilized as the design materials to develop turbine blades in gas turbines due to their excellent high-temperature properties. Gas turbine blades are exposed to extreme loading histories that combine high mechanical and thermal stresses. Both directionally solidified (DS) and single crystal NBSAs are used throughout the industry because of their superior tensile and creep strength, excellent low cycle fatigue (LCF), high cycle fatigue (HCF), and thermomechanical fatigue (TMF) capabilities. Directional solidification techniques facilitated the solidification structure of the materials to be composed of columnar grains in parallel to the <001> direction. Due to grains being the sites of failure initiation the elimination of grain boundaries compared to polycrystals and the alignment of grain boundaries in the normal to stress axis increases the strength of the material at high temperatures. To develop components with superior service capabilities while reducing the development cost, simulating the material’s performance at various loading conditions is extremely advantageous. To support the mechanical design process, a framework consisting of theoretical mechanics, numerical simulations, and experimental analysis is required. The absence of grain boundaries transverse to the loading direction and crystallographic special orientation cause the material to exhibit anisotropic behavior. A framework that can simulate the physical attributes of the material microstructure is crucial in developing an accurate constitutive model. The plastic flow acting on the crystallographic slip planes essentially controls the plastic deformation of the material. Crystal Visco-Plasticity (CVP) theory integrates this phenomenon to describe the effects of plasticity more accurately. CVP constitutive models can capture the orientation, temperature, and rate dependence of these materials under a variety of conditions. The CVP model is initially developed for SX material and then extended to DS material to account for the columnar grain structure. The formulation consists of a flow rule combined with an internal state variable to describe the shearing rate for each slip system. The model presented includes the inelastic mechanisms of kinematic and isotropic hardening, orientation, and temperature dependence. The crystallographic slip is accounted for by including the required octahedral, cubic, and cross slip systems. The CVP model is implemented through a general-purpose finite element analysis software (i.e., ANSYS) as a User-Defined Material (USERMAT). Uniaxial experiments were conducted in key orientations to evaluate the degree of elastic and inelastic anisotropy. The temperature-dependent modeling parameter is developed to perform non-isothermal simulations. A numerical optimization scheme is utilized to develop the modeling constant to improve the calibration of the model. The CVP model can simulate material behavior for DS and SX NBSAs for monotonic and cyclic loading for a range of material orientations and temperatures.

scholarly journals Calculation of accurate interatomic contact surface areas for the quantitative analysis of non-bonded molecular interactions

2019 ◽  
Vol 35 (18) ◽  
pp. 3499-3501 ◽  
Author(s):  
Judemir Ribeiro ◽  
Carlos Ríos-Vera ◽  
Francisco Melo ◽  
Andreas Schüller
Keyword(s):  
Surface Area ◽  
Contact Surface ◽  
Web Server ◽  
Software Tool ◽  
Solvent Accessible Surface Area ◽  
Surface Areas ◽  
Contact Surfaces ◽  
Accessible Surface ◽  
Solvent Accessible Surface ◽  
Interatomic Contact

Abstract Summary Intra- and intermolecular contact surfaces are routinely calculated for a large array of applications in bioinformatics but are typically approximated from differential solvent accessible surface area calculations and not calculated directly. These approximations do not properly take the effects of neighboring atoms into account and tend to deviate considerably from the true contact surface. We implemented an extension of the original Shrake-Rupley algorithm to accurately estimate interatomic contact surface areas of molecular structures and complexes. Our extended algorithm is able to calculate the contact area of an atom to all nearby atoms by directly calculating overlapping surface patches, taking into account the possible shielding effects of neighboring atoms. Here, we present a versatile software tool and web server for the calculation of contact surface areas, as well as buried surface areas and solvent accessible surface areas (SASA) for different types of biomolecules, such as proteins, nucleic acids and small organic molecules. Detailed results are provided in tab-separated values format for analysis and Protein Databank files for visualization. Direct contact surface area calculation resulted in improved accuracy in a benchmark with a non-redundant set of 245 protein–DNA complexes. SASA-based approximations underestimated protein–DNA contact surfaces on average by 40%. This software tool may be useful for surface-based intra- and intermolecular interaction analyses and scoring function development. Availability and implementation A web server, stand-alone binaries for Linux, MacOS and Windows and C++ source code are freely available from http://schuellerlab.org/dr_sasa/. Supplementary information Supplementary data are available at Bioinformatics online.

Part II. Research on the Performance of a Type of Internally Air-cooled Turbine Blade

1953 ◽  
Vol 167 (1) ◽  
pp. 351-370 ◽  
Author(s):  
D. G. Ainley
Keyword(s):  
Gas Flow ◽  
Thermal Stresses ◽  
Turbine Blades ◽  
Small Diameter ◽  
Rotor Blades ◽  
Air Cooling ◽  
Gas Temperature ◽  
Flow Through ◽  
Cooling Air ◽  
Practical Feasibility

A comprehensive series of tests have been made on an experimental single-stage turbine to determine the cooling characteristics and the overall stage performance of a set of air-cooled turbine blades. These blades, which are described fully in Part I of this paper had, internally, a multiplicity of passages of small diameter along which cool air was passed through the whole length of the blade. Analysis of the, test data indicated that, when a quantity of cooling air amounting to 2 per cent, by weight, of the total gas-flow through the turbine is fed to the row of rotor blades, an increase in gas temperature of about 270 deg. C. (518 deg. F.) should be permissible above the maximum allowable value for a row of uncooled blades made from the same material. The degree of cooling achieved throughout each blade was far from uniform and large thermal stresses must result. It appears, however, that the consequences of this are not highly detrimental to the performance of the present type of blading, it being demonstrated that the main effect of the induced thermal stress is apparently to transfer the major tensile stresses to the cooler (and hence stronger) regions of the blade. The results obtained from the present investigations do not represent a limit to the potentialities of internal air-cooling, but form merely a first exploratory step. At the same time the practical feasibility of air cooling is made apparent, and advances up to the present are undoubtedly encouraging.

Design Optimization of T-Root Geometry of a Gas Engine HP Compressor Rotor Blade for Lifing the Blade Against Fretting Failure

2016 ◽  
Author(s):  
Kumar K. Gowda ◽  
S. L. Ajit Prasad ◽  
Vinayaka Nagarajaiah
Keyword(s):  
Design Optimization ◽  
Turbine Blades ◽  
Wake Flow ◽  
Element Analysis ◽  
Gas Engine ◽  
Blade Root ◽  
Compressor Rotor ◽  
Blade Optimization ◽  
Engine Failure ◽  
Practical Geometry

Stress Concentration Factor (SCF) is significant in machine elements as it gives rise to localised stresses which lead to peak stresses introducing cracks which propagate further and hence the component fails before the desired design life. Turbine blades are subjected to high centrifugal stresses and vibratory stresses in a Gas Engine HP Rotor. The vibratory stresses arise due to air wake flow excitations called Nozzle Passing Frequency (NPF). Hence, Turbomachinery industry calls for an optimum structurally rigid blade root geometry. An optimum blade root was defined, as a root with practical geometry, which when loaded returns the minimum fillet SCF. In the present work an approach has been done for design optimization of fillet stresses at sharp edges of T-root blade, optimization of platform dimensions, shank dimensions, root land dimensions and to ensure that stress distribution is uniformly spread along the filleted width of the root land on both sides of the blade, which otherwise will lead to crack initiation, propagation and hence, fretting failure at blade root lands. This may further lead to blade lift and effect on stage and overall gas engine failure over a period of cycles. Hence, a special attention is made on SCF of the T root -blade which fails and to guarantee for safe and reliable operation under all possible service conditions. Finite Element Analysis (FEA) is used to determine the fillet stresses and Peterson’s SCF chart is effectively utilized to modify the blade root. The root is modified due to the difficulty in manufacturing the butting surface of the tang which grips the blade to the disk crowns having small contact area. The blade height is suitably designed using Campbell diagram by ensuring the working frequency is well within 6e excitations for the specified operating speeds. Hence, increasing the life of the HP compressor blade.

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