Gas Turbine Engine Blades Research Articles

Evaluation of the limiting pressure and geometry of capsules in the gas turbine engine blade crack detection system under conditions of unsteadiness and temperature unevenness

The problem of optimization of the system for diagnosing damage in the blades of gas turbine engines in nonstationary conditions is considered. A model for calculating the pressure inside a capsule with an ionizing substance is proposed, taking into account the centrifugal gas forces and the non-uniformity of the temperature field. Expressions are obtained for determining the minimum possible diameter of capsules placed in the blade body in order to increase the effectiveness of the crack detection system. It was established that the pressure in the volume of the capsule varies exponentially in the radial direction with the highest value in the peripheral section of the blade. Keywords: turbine blade, centrifugal force, temperature non-uniformity, non-stationarity ivan_andrianov_90@mail.ru, el.chep@bk.ru

THE SIMULATION OF EMERGENCY ACTION ON CONSTRUCTION MATERIALS BY HIGH CURRENT RELATIVISTIC ELECTRON BEAMS

Development of many innovative areas in energy, mechanical engineering, aircraft building and other industries is limited by the strength of materials under the action of temperature gradients. In this regard, the problem appears to find and justify technical means to model a complex of operating conditions. High-current relativistic electron beams reasonably belong to such instruments and means. As a result of their impact, pulsed electric and magnetic fields occur in the irradiated targets, temperature gradients are created, and shock waves are generated. The paper investigates the patterns of change in the internal structure of the blades of gas turbine engines and engineering materials, subjected to the action of an electron beam

Engineering-Physical Method for Determining the Thermal Conductivity of Objects with Micrometric Thickness and a Complex Structure

Introduction. The application of functional coatings on products, the performance properties of which are localized in the surface layer is a trend in modern mechanical engineering and materials science. The issues considered in this regard are relevant, in particular, for thermal-barrier coatings of turbine blades of steam and gas turbine engines. It is worth mentioning the materials that experience significant thermal loads during operation. In this case, the lack of reliable methods for predicting the thermophysical properties of the coating seems to be a problem. The work objective is to create a computational and analytical methodology for determining the thermal conductivity of coatings. This approach is based on experimental data and takes into account structural parameters of the material.Materials and Methods. The experiments were carried out with the blades of a high-speed gas turbine of a locomotive engine made of heat-resistant chromium-nickel alloy Inconel 713LC. An experimental multiphase coating of the Nb-Ti-Al intermetallic system with a thickness of about 80 microns was applied using vacuum ion-plasma technology. The two-beam scanning electron microscope Zeiss CrossBeam 340 was used in the work. The thermal conductivity of the coatings was determined by an experimental technique based on the measurement of the contact potential difference (CPD). Numerical values of this difference were obtained using a mirror galvanometer with high voltage sensitivity. A special signal amplifier and a USB oscilloscope were used to record the readings.Results. The calculation apparatus of the thermal conductivity determination technique is based on the experimental values of ∆φ CPD:– for the base metal (Inconel 713LC) +846 mkV;– for the coating Nb-Ti-Al – 90 mkV.The solution to the problem of the distribution of particles in a force field with a potential difference ∆φ is described by the Boltzmann distribution. Starting from the obtained result, we get:– CPD at the boundary of the contacting metals;– energy and thermal conductivity of the Fermi level;– electron relaxation time.The multidirectional influence that the dimensional differences of the particles of the second phase have on the effective thermal conductivity is considered. For this case, a dimensionless value of the effective thermal conductivity in the direction of each axis and the effective thermal conductivity of the composite are found. Porosity is taken into account according to the Maxwell – Aiken dependence and introduced into the general calculation system. The thermal conductivity of Nb-Ti-Al is established: λNbTiAl = 4,76 W/m.K. Thus, the thermal barrier coating Nb-Ti-Al fully meets its functional purpose.Discussion and Conclusion. The method of determining thermal conductivity described in the article is applicable only to conductive consolidated materials or composites with a continuous conductive matrix. The presented work completes the initial stage of creating a computational and analytical model for predicting the thermal conductivity of materials and coatings. The results of testing the model for materials with a complex structure showed its satisfactory accuracy. This indicates the expediency of using the two considered elements of the model. The first one is the instrumental measurement of the CPD. The second one is taking into account the features of the structural and phase state of the material. With the development of the model, it is expected to overcome its weaknesses:– the impossibility of using non-conductive objects to determine the thermal conductivity;– a significant decrease in the accuracy of determining thermal conductivity for materials and coatings with a gradient structure.

THE USE OF CERAMIC FILTERS IN THE SMELTING OF WORKPIECES FROM HEAT-RESISTANT ALLOYS

To improve the operational characteristics of gas turbine engine blades, it is necessary to use new methods of cleaning and refining metal. Melt filtration is an effective way to improve casting quality.According to the conducted analyses, it was determined that the amount of conditioned waste generated during the smelting of products reaches 27% of the mass of the spent charge, and non-conditioned waste rejected during LUMMA control is 23%. The results of the statistical analysis show that the total amount of waste generated during the smelting of gas turbine blades is, on average, 60–70% of the weight of the loaded charge.The purpose of the work is to create a new composition of the ceramic mixture for the production of high-strength filters, as well as the development of technology for the production of gas turbine parts using them.The analysis was performed on samples of heat-resistant corrosion-resistant alloy CM88Y. The alloy for research was melted from the primary charge on the UPPF-3M foundry unit. As a result of the work carried out, a new rational composition of the mixture for the manufacture of ceramics was created, which allows to increase the characteristics of strength and heat resistance. An instruction was created for the manufacture of ceramic filters at machine-building enterprises. To eliminate damage to ceramic rods in blades under the influence of thermal shock, improved systems for filtering metal in a liquid state and filling ceramic molds are proposed. Uniform temperature distribution across the cross-section of the casting also reduces the number of defective products.

A new approach to protect and extend longevity of the thermal barrier coating by an impermeable layer of silicon nitride

AbstractA sample representation of a gas turbine engine blade, consisting of a nickel superalloy substrate with a deposited thermal barrier coating (TBC), was covered with silicon nitride, Si3N4, as an impermeable layer using plasma enhanced chemical vapor deposition (PECVD). The silicon nitride layer was used to seal the topcoat of yttria‐stabilized zirconia (YSZ) surface of the TBC to mitigate calcium–magnesium–aluminum–silicon oxide (CMAS) attack. CMAS testing was carried out on the covered and uncovered surfaces by melting a ratio of 25 mg/cm2 of CMAS powder onto the surface of each sample in a furnace at 1100°C for 1 h. The conformal surface reaction of the sealed layer confirmed no cracking or delamination at high temperatures. Scanning electron microscopy (SEM) micrographs confirmed that the surface of YSZ was successfully sealed. The new coating of silicon nitride was shown to be a viable solution and technique to significantly block CMAS infiltration in porous thermal barrier coatings.

Design and Analysis of Alternative Coating Bio-Material for Gas Turbine Engine Blade for High Temperature Aerospace Application

Design and Analysis of Alternative Coating Bio-Material for Gas Turbine Engine Blade for High Temperature Aerospace Application

Vacuum plasma erosion resistant 2D nanocomposite coating Avinit for compressor blades of gas turbine engines of aircraft engines

The work is devoted to the search for new vacuum-plasma coatings with high hardness to increase the durability of the compressor blades of the GTE of aircraft engines Ti-Al-N-based vacuum-plasma coatings obtained by Avinit technologies, which ensure the application of hard, high-quality coatings with dramatically reduced micro-arc damage, were selected as candidates. Avinit multilayer coatings have higher functional characteristics than TiN (microhardness, crack resistance, temperature resistance, erosion and corrosion resistance) and may be promising for applying erosion-resistant coatings for compressor blades. Avinit technologies are technologically closest to the vacuum-plasma technologies used in industrial production for applying TiN protective coatings. New multi-layered 2D nanocomposite wear-resistant ion-plasma hard coatings Avinit (TiN-AlN)n have been developed. The created software products made it possible to reach a qualitatively new level in terms of further modification and improvement of the designs of Avinit functional coatings, stability of technologies and improvement of their quality control when applying such coatings for use in the production of compressor blades of gas turbine engines of aircraft engines. Special attention is paid to methods of preliminary ion-plasma treatment of surfaces before coating. Metallographic studies of the chemical and phase composition and structure of Avinit (TiN-AlN)n coatings have been carried out. The thickness of the coatings is 7-9 μm, the microhardness is 34-35 GPa (compared to the serially used TiN coating: 27.4 GPa). The use of three-stage ion-plasma treatment in Avinit technologies using a double vacuum-arc discharge followed by the application of strengthening coatings in a single technological cycle eliminates the formation of cracks and ensures the production of tightly bonded, high-quality coatings of a given composition with the maximally reduced share of the droplet component. The developed coatings (TiN-AlN)n were applied to experimental batches of working compressor blades of GTE aircraft engines for bench tests.

STUDY OF NANOMODIFICATION OF NICKEL ALLOY GS3 WITH TITANIUM CARBIDE

The work deals with the fundamentals of nanomodification of the GS3 heat-resisting multicomponent nickel alloy, out of which blades for gas turbine engines are made. The selection of the modifier for the experimental alloy was justified; the technology of acquiring the nanomodifier, using the plasma-chemical synthesis method, was developed; and the calculations of the specific surface of the TiC particles were performed. The required quantity of nanomodifier introduced to the liquid alloy to acquire the set structure was determined experimentally. Through electronic microprobe analysis, introduction to the metal matric of nanoparticles of titanium carbide is approved. Nanomodification allows achieving refinement of the GS3 nickel alloy structure, which is going to provide an opportunity to increase the effective life of gas turbine engine blades.

Bayesian optimization with active learning of design constraints using an entropy-based approach

The design of alloys for use in gas turbine engine blades is a complex task that involves balancing multiple objectives and constraints. Candidate alloys must be ductile at room temperature and retain their yield strength at high temperatures, as well as possess low density, high thermal conductivity, narrow solidification range, high solidus temperature, and a small linear thermal expansion coefficient. Traditional Integrated Computational Materials Engineering (ICME) methods are not sufficient for exploring combinatorially-vast alloy design spaces, optimizing for multiple objectives, nor ensuring that multiple constraints are met. In this work, we propose an approach for solving a constrained multi-objective materials design problem over a large composition space, specifically focusing on the Mo-Nb-Ti-V-W system as a representative Multi-Principal Element Alloy (MPEA) for potential use in next-generation gas turbine blades. Our approach is able to learn and adapt to unknown constraints in the design space, making decisions about the best course of action at each stage of the process. As a result, we identify 21 Pareto-optimal alloys that satisfy all constraints. Our proposed framework is significantly more efficient and faster than a brute force approach.

Optimization Model of the Shell Capsules Geometry for a System for Diagnosing Damage to Gas Turbine Blades in Non-stationary

Scientific research is devoted to the problem of diagnosing damage in the blades of gas turbine engines in non-stationary conditions. The paper proposes a model for a more accurate calculation of the parameters of the crack detection system using a system of capsules, inside of which, under the influence of pressure, there is a substance exhibiting ionizing properties. In the study, the relations for determining the uneven pressure due to the action of centrifugal tensile forces during the rotation of the turbine blade are obtained. The relations for calculating the minimum required diameter of the capsule to ensure the rupture of the capsule when cracks are opened for the effective operation of the crack detection system are obtained. Calculations of the pressure inside the capsule and the geometry of the capsule at different speeds of rotation of the turbine blade are carried out. An estimate of the error in calculating the pressure inside the capsule is given in the case of not taking into account the action of centrifugal forces. The obtained dependences will significantly optimize the system for detecting damage to turbine blades, and increase the efficiency and safety of the operation of gas turbine engines.

The method of calculating the minimum creep rate of turbine blades of gas turbine engines based on the degradation of the alloy microstructure

In the current global economic conditions, airlines need to curtail financial expenses. It is known that the share of airline costs for maintenance and repair (MR) in the total cost structure amounts to at least 20%, of which more than 40% is for the repair and maintenance of aircraft engines (AE). According to the actual expertise, this item of expenditure will continue to grow due to the inevitable sophistication of AE structures, which is specified by the need to increase the efficiency and ecological compatibility. One of the possible ways of curbing maintenance and repair expenses is to transit for the operation of on-condition components which are currently in operation until the overhaul life is exhausted. For example, turbine blades of gas turbine engines (GTE) can be pertinent to such elements. It is a common fact that turbine blades operate in challenging environment: they are affected by excessive temperatures, severe centrifugal loads, aggressive gas media, and their destruction generally occurs because of the accumulation of fatigue damage and creep. The alloy microstructure significantly degrades and deforms before macroscopic damage develops. The early detection of microscopic damage in the alloy is the tool which allows for the transition to GTE oncondition turbine blades operation. The article presents the method for calculating the minimum creep rate of the Inconel 738LC alloy based on microstructural changes under operating conditions. The obtained results are proposed to be used for calculating the residual life of turbine blades by the creep parameter.

ОСОБЕННОСТИ ПРИМЕНЕНИЯ МНОГОКООРДИНАТНЫХ ШЛИФОВАЛЬНЫХ СТАНКОВ С ЧПУ ДЛЯ ПОВЫШЕНИЯ ПРОИЗВОДИТЕЛЬНОСТИ, КАЧЕСТВА И ТОЧНОСТИ ОБРАБОТКИ ДЕТАЛЕЙ И УЗЛОВ АВИАЦИОННЫХ ГАЗОТУРБИННЫХ ДВИГАТЕЛЕЙ

The paper is aimed at improving the productivity, quality and accuracy of manufacturing gas turbine engine parts and assemblies for the modern growing passenger aviation transport based on the use of technical capabilities of modern multiaxis CNC grinding machining centers. The paper shows the results of successful application of a five-axis CNC grinding machining center MFP-050.65.65 made by Magerle (Switzerland), which allows reducing by five times the number of operations, universal machines, special devices and cutting tools by increasing the number of machined surfaces for one set of nozzle blades of an aviation gas turbine engine. Simultaneously with a significant increase in the productivity of machining various multidirectional surfaces of the nozzle blades due to the use of new highly porous grinding wheels and rational modes of deep grinding, a higher burn-free quality of the ground surfaces is ensured and an important task is solved to increase the accuracy of the flow sections of the turbine nozzle apparatus with the combined use of CNC system and special software for correcting errors of part casting surfaces during their installation, turning and deep grinding of the base surfaces. The developed new technology of nozzle blades machining was introduced for the first time in the Russian Federation at the Aviadvigatel enterprise for manufacturing nozzle blades of modern newly produced gas turbine engines.

Analysis of a Single Crystal Solidification Process of an Ni-based Superalloy using a CAFE Model

The efficiency of gas turbines depends on the gas turbine working temperature. Single crystal blades are being applied more often than equiaxed blades in gas turbine engines, to increase the turbine inlet temperature, resulting in enhanced turbine engine efficiency. Single crystal blades endure creep conditions at high temperature better than polycrystal blades because the single crystals do not include grain boundaries. The single crystal process is a breakthrough technology, however, production yield is relatively low compared with polycrystal, and their mechanical properties depend on the crystallographic orientation of the single crystals. In this study, a thermal simulation model, the 3D cellular automation-finite element (CA-FE), was used on the single crystal process with the Bridgman method. The simulation model was well expected, by analysis of the microstructure and EBSD, on the grain selection in the single crystal process. The evolution of single crystal grains was analyzed on process of grain selection in start block and spiral selector. Single crystal orientation was also investigated to determine the effect of nucleation density, forming in the initial stage of solidification.

Hydrogen and Corrosion Resistance of Nickel Superalloys for Gas Turbines, Engines Cooled Blades

The paper presents the results of the analysis of the resistance to hydrogen and high-temperature salt corrosion of the developed alloy of the CM88Y type for the turbine blades of gas turbine engines for marine and power purposes in comparison with the industrial heat-resistant corrosion-resistant alloy CM88Y and the alloy for the protective coating of the SDP3-A blades. SDP3-A alloy was chosen as a reference sample, which has high hydrogen and corrosion resistance. The new heat-resistant alloy additionally contains such refractory metals as rhenium and tantalum, which are added to the composition of the alloy in order to increase operational characteristics while maintaining phase-structural stability. These are properties such as long-term and fatigue strength, characteristics of plasticity and strength at room and elevated temperatures. Therefore, the purpose of these studies was to determine the resistance to high-temperature salt corrosion of the developed alloy in comparison with the industrial heat-resistant nickel alloy and to evaluate the influence of alloying, hydrogen embrittlement of CM88Y and ZhS3DK alloys with different contents of chromium, boron, zirconium, hafnium, and yttrium were compared. The corrosion resistance of the materials was evaluated after crucible tests in a salt solution at a temperature of 900 °C for 30 h, according to the standard method. The corrosion resistances of alloys were determined by the mass loss, corrosion rate, and data from metallographic studies.

РАСЧЁТНОЕ ПРОГНОЗИРОВАНИЕ ТЕХНОЛОГИЧЕСКИХ ОСТАТОЧНЫХ ДЕФОРМАЦИЙ ПРИ ИЗГОТОВЛЕНИИ ДЕТАЛЕЙ, ПОДВЕРГАЕМЫХ УПРОЧНЕНИЮ ПОВЕРХНОСТНЫМ ПЛАСТИЧЕСКИМ ДЕФОРМИРОВАНИЕМ

Ensuring the geometric accuracy of critical parts is an actual problem for aviation industry enterprises. The blades of gas turbine engines are particularly critical and technologically complex parts. In most cases, the interlocks of the blades, as well as the blade, are subjected to surface shot peening. Residual stresses are the first cause of the appearance of technological residual deformations. It is the residual deformations caused by the action of residual stresses that in most cases are the cause of critical defects of parts. Thus, the development of scientifically based approaches to modeling residual stresses and calculating technological residual deformations is an actual task. The paper presents an approach that allows at the stage of machining to take into account the deformations that can be obtained at the final stages of manufacturing parts after shot peening strengthening. The approach is based on preliminary computational prediction of technological residual deformations from the action of residual stresses based on analytical and finite element methods. The implementation of the approach is shown on the example of a compressor blade of a gas turbine engine, subjected to hardening by shot peening over the entire surface of the part.

Development of manufacturing technology for compressor blades of gas turbine engine using two-axis presses

The manufacturing process of forgings of blades made of titanium alloys with different geometry of the locking part is considered. A comparison is made of a typical method for manufacturing of a blade forging with several upsetting passes with a newly developed technological process using a two-axis hydraulic press. Experimental data of computer simulation of the extrusion process on a two-axis hydraulic press are presented, which made it possible to obtain an experimental batch of titanium blades.

Increasing the erosion resistance of compressor blades of gas turbine engine and gas pumping unit by applying vacuum-plasma coatings

A test for resistance to gas-abrasive wear of several variants of multilayer vacuum-plasma coatings based on titanium and vanadium nitrides of various thicknesses and number of layers was carried out. Erosion curves are given, areas of accelerated wear are determined, and comparative values of wear resistance are calculated. Based on the conducted microscopic studies, a mechanism of layer-by-layer wear of the studied multilayer coatings is proposed. It is shown that due to the creation of a special layered coating structure, including the alternation of highly hard nitride and relatively softer Ti and V layers, the resistance to gas-abrasive wear of parts of gas turbine engines made of titanium alloys is greatly increased.

Overview of technical solutions for improving of magnetron sputtering devices

The paper provides a brief overview of technical solutions that allow expanding the capabilities of magnetron sputtering systems using different options for organizing an external source of charges. Among them, the following are considered in detail: electron emission in the magnetron discharge track; argon ionization in the space above the target; argon ionization in the vacuum chamber volume; the use of an uncooled "hot" target; bombardment of the target surface with a beam of argon ions. Among the solutions considered, a combination of a magnetron with an ion source or an incandescent cathode is noted, which in principle can provide equal-dimensional reactive sputtering on "long" (more than 1 m) magnetrons and flexible control of the properties of coatings intended for dimensional elements of equipment of the fuel and energy and oil and gas complexes, as well as solutions based on spraying a "hot" target, which can find industrial application for the formation of thermal barrier coatings on the blades of modern power gas turbines and aviation gas turbine engines.

CAMERA: A method for cost-aware, adaptive, multifidelity, efficient reliability analysis

Estimating probability of failure in aerospace systems is a critical requirement for flight certification and qualification. Failure probability estimation involves resolving tails of probability distributions, and Monte Carlo sampling methods are intractable when expensive high-fidelity simulations have to be queried. We propose a method to use models of multiple fidelities that trade accuracy for computational efficiency. Specifically, we propose the use of multifidelity Gaussian process models to efficiently fuse models at multiple fidelity, thereby offering a cheap surrogate model that emulates the original model at all fidelities. Furthermore, we propose a novel sequential acquisition function based experiment design framework that can automatically select samples from appropriate fidelity models to make predictions about quantities of interest at the highest fidelity. We use our proposed approach in an importance sampling setting and demonstrate our method on the failure level set and probability estimation on synthetic test functions and two real-world applications, namely, the reliability analysis of a gas turbine engine blade using a finite element method and a transonic aerodynamic wing test case using Reynolds-averaged Navier-Stokes equations. We show that our method predicts the failure boundary and probability more accurately and at a fraction of the computational cost compared with using just a single expensive high-fidelity model. Finally, we show that our sequential approach is guaranteed to asymptotically converge to the true failure boundary with high probability.

Mathematical Modeling of Loading for Remanufactured Compressor Blades of Gas Turbine Engines

Mathematical Modeling of Loading for Remanufactured Compressor Blades of Gas Turbine Engines