Gas Turbine Engine Parts Research Articles

Requirements for the order and the procedure of estimating structural strength characteristics of metal alloys for the main and critical parts of aviation gas turbine engines

Requirements of the technical regulations for the order and procedure of estimating structural strength of metal alloys used in critical and main parts of aviation engines in their certification are outlined in the paper. The scope of work to be carried out by the engine designer, the developer of the material/semi-finished product and the engine manufacturer to confirm the compliance with the mentioned requirements is described. The tasks to be solved at different stages of general and special qualification of the material are discussed. The spectrum of the main mechanical characteristics of alloys, including mono-crystal alloys, to be determined during the qualification tests is presented. The standards in accordance to which the tests are to be performed are mentioned. Relationships for the determination of the material characteristics to be used in estimating the strength and service life of engine parts are given. The requirements for the statistical processing of the results of investigating the structural strength of alloys are discussed, as well as the requirements for setting the values of the mechanical properties guaranteed in the delivery of materials/semi-finished products. The necessity to have data on possible presence of different defects in the main (critical for safe operation) engine parts is mentioned. The reference list includes principal technical regulations the requirements of which are to be met during special qualification of alloys used for the manufacture of the main and critical aviation engine parts.

The determination of power characteristics of isothermal roll formation of critical parts of gas-turbine engines

One of the most promising methods in manufacturing axisymmetric aircraft parts such as disks or hollow shafts is the isothermal roll formation in the state of superplastic deformation (SPD) on specialized reeling machines. Equipment of this class is designed on the basis of calculating the power characteristics expected from these machines. The procedure is efficiently carried out by mathematical modeling. This paper presents a technique for drawing the finite element model of isothermal roll formation in the state of superplasticity as well as the results of this modeling, exemplified by the manufacture of a disk from BT9 heat-resistant titanium alloy. The suggested technique is used in the development of technology and the design of equipment for rolling axisymmetric parts (disks, hollow shafts) from heat-resistant titanium and nickel alloys.

CONTROL THE SHAPE AND POSITION OF THE PROFILE BLADES OF THE BLISK OF A GAS TURBINE

Rotor blades and turbine engine blisk and installations are being monitored closely in all important characteristics and parameters as before Assembly and after it. The most important parameters of the blisk are its geometric and dimensional characteristics. One of the objectives of the control of complex parts and assemblies gas turbine engine (GTE) and gas turbine units (GTU) is providing them with the specified dimensional and geometric characteristics. Traditional methods for the assessment of geometric and dimensional characteristics of GTE parts and GTU are often characterized by a lack of clear relationships between multiple heterogeneous measured parameters details that are often not objectively evaluate the part or host their functional purpose. This circumstance leads to unjustified rejection of parts that are within an acceptable range of values, or, even more dangerous, not rejected parts, which on the operational properties may not meet the specified. Traditional methods of controlling the shape and position of the profile blades is as follows. The blade and the template still fixed in the base device, the profile shape of the blade in the specified section of the control using templates, and the position control in the tangential direction relative to the theoretical axis of the scapula using the depth gauge. The monitoring is performed in at least three sections. The use of traditional methods to control the shape and position of the blades with respect to the estimation of the parameters of the blisk may result in an error. It is associated with several factors such as stationary fixation of the template, leading to a number of constraints to control the shape and position of the blade relative to its theoretical axis, which leads to unjustified rejection of a suitable product. In this regard, the company LLC Turbinectomies with Ufa state aviation technical University Ufa state oil technical University was developed and investigated a new method to control the shape and position of the blades of the blisk, in both the new and restored when repairing the gas turbine blades. To create the specified technique was to increase the reliability of the control blades of the blisk and, as a consequence, reducing the number of rejected products.

Application of the technology of pulsed laser surface coating in correcting casting defects of parts made of «ЖС-32» alloy

Production of casts of parts of gas turbine engines (GTE) is a complex and expensive process that requires a considerable amount of material resources. Various defects often occur in the manufacture of complex parts of gas turbine engines, defects that can be corrected in various ways. This paper describes a method of correcting defects in a cast alloy stator by pulsed laser cladding of stainless steel elements. After deseaming the unsound spots were reconstructed using a wire selected by matching its chemical composition with the basic material, annealing being used at different stages of surface coating. Annealing of the basic metal prior to deposition results in a two-fold increase of the transition area, the difference in the properties of the basic material and the cladding is maintained. If annealing takes place after cladding there is no clearly defined borderline between the basic materials and the steel deposited. Annealing and final hardening heat treatment is required after stainless steel is deposited on the nickel alloy.

Experimental determination of thermal-fatigue life of turbine blades with various coatings made of an advanced heat resistant nickel alloy

An original CIAM know-how for the experimental determination of thermal-fatigue life of parts of the gas-turbine engine hot section, including parts with heat-resistant and ceramic thermal barrier coatings, in the conditions of superficial uneven heating by high-frequency currents with continuous cooling of the parts at the preset air consumption is outlined in the paper. The possibility of using high-frequency heating of the parts with coatings (including thermal protection coatings) for modeling superficial heating of full-scale parts of gas-turbine engines is shown on the basis of the tests of model samples with coatings controlling the temperature of the surface by means of a thermal imager. The method used makes it possible to simulate the thermal state of the part in the operating conditions. Temperature differences observed both over the surface and the thickness of a part create thermal stresses in the material, similar to those arising during the operation of the engine. If necessary, mechanical loads synchronized with changes in temperature, to simulate for example, the centrifugal force may be applied to the part. The article presents the results of experimental studies of thermal-fatigue life of rotor blades of the 1st stage of the turbine made of an advanced monocrystal alloy VZhM-5 without coating and with various protective coatings, conducted according in the regime Tmin↔Tmax = 350↔1050˚C.

Requirements for the order and the procedure of estimating structural strength characteristics of metal alloys for the main and critical parts of aviation gas turbine engines

Requirements of the technical regulations for the order and procedure of estimating structural strength of metal alloys used in critical and main parts of aviation engines in their certification are outlined in the paper. The scope of work to be carried out by the engine designer, the developer of the material/semi-finished product and the engine manufacturer to confirm the compliance with the mentioned requirements is described. The tasks to be solved at different stages of general and special qualification of the material are discussed. The spectrum of the main mechanical characteristics of alloys, including mono-crystal alloys, to be determined during the qualification tests is presented. The standards in accordance to which the tests are to be performed are mentioned. Relationships for the determination of the material characteristics to be used in estimating the strength and service life of engine parts are given. The requirements for the statistical processing of the results of investigating the structural strength of alloys are discussed, as well as the requirements for setting the values of the mechanical properties guaranteed in the delivery of materials/semi-finished products. The necessity to have data on possible presence of different defects in the main (critical for safe operation) engine parts is mentioned. The reference list includes principal technical regulations the requirements of which are to be met during special qualification of alloys used for the manufacture of the main and critical aviation engine parts.

Procedure of creating three-dimensional solid models of tool electrodes for electrochemical pulse machining of gas turbine engine parts in CAD-systems with their parametric coupling with software module profiling

This work is dedicated to the creation of parametric solid models of tool electrodes based on the results of the calculation of the previously created software module. The developed technique will facilitate the solution of the problem of technological preparation of the operation of electrochemical machining (ECM) of a gas turbine emgine copressor. In this case, the solution could be obtained by simulations in several iterations and would completely preclude all machine work and mechanical hand-operated development of electrodes. The technique is based on a mathematical model of electrochemical shaping of a gas turbine engine airfoil using pulse current. In developing the model the electric comductivity and temperature were taken to be constant, the current output depended only on the current density, the anode and cathode overvoltage was determined by the polarization curves, the peculiarities of the anode process dynamics were considered by the current density and the parameters of the hydrodynamic conditions were taken to be optimal. A software module was developed in the course of developing the procedure. The module developed provides easy implementation of a mathematical model of profiling tool electrodes in ECM. Electronic models of electrode profiles that could be used in producing control software for machining electrode profiles on CNC machines are the end result of such simulation.

New possibilities of using spin rigs to provide gas turbine engine strength reliability

The main tasks of using spin rigs for carrying out certification, engineering and technological tests of gas turbine engine parts and assemblies are formulated. Specific design features of spin rigs are described in the paper. The main characteristics of the spin rigs used at CIAM are presented. The peculiarities of carrying out different tests using spin rigs and the main requirements for rigs are discussed. Examples of using spin rigs for carrying out tests are given. Examples of using the rigs are given, among them are tests intended to confirm the rotor load capacity or technological hardening of the rotor material; equivalent-cyclic tests to confirm the rotor life; investigation of the vibration properties of rotating parts (optimization of structural damping of vibrations and specifying high-cycle fatigue of rotating blades, etc.); tests carried out to confirm the containment of rotor fragments in the engine casing and to determine the rotor integrity under the impact of bird or other foreign objects sucked in the engine gas-air flow duct. The necessity of combining spin rig tests with calculations and physical investigations is shown. The main directions of updating spin rigs are considered. In particular, the necessity of developing rigs for different tests of engine fans with high bypass ratios; perfecting rigs and testing procedures for high-cycle fatigue investigations of rotating blades; producing the equipment for thermal cycling tests of rotor parts, especially parts made of composite or ceramic materials; investigation of vibrations in the conditions of rotor-stator contact; improvement of hardware and methods.

Research of the validity of forecasting low cycle durability of gas turbine engine parts based on Manson’s equation

The article presents the prediction of low-cycle durability of gas turbine discs and test samples by the method of universal tilt on the basis of the Manson equation and its various modifications. Manson equation obtained by testing of standard specimens in stretching-compression, i.e. an uniaxial stress state and the symmetric cycle of loading. Under complex stress-strain state in the modification of the equations embeded the mean stress of the cycle, but clear guidance for determining it are missing. In this paper we proposed different ways to imagine the average stress. On the basis of verification of various modifications were adopted, the results of tests of standard specimens with circular cross-sections, samples of the lock "swallow's tail" cut from the disks of the compressor, as well as full-scale drive of new and used. The test was carried out from zero cycle of loading close to the real operating conditions of main parts of the gas turbine engine. By comparison of calculation results with the experimental data revealed the most effective ways to refine the Manson equations. It was found a significant effect on low cycle durability of not only the magnitude of deformation of the parts, but the type of stress-strain state. Therefore, the most effective was the using of the stress intensities. It was also established that the refinement equation, introduced by Manson and Muralidharan applicable only for stress states that are close to flat.

Development of a technique of molding small complex parts of gas turbine engines from high-temperature alloys using additive technologies

Rapid prototyping technologies provide a unique opportunity to receive cost-effective solutions for theproduction of parts by investment casting. Research and development of rapid prototyping technologies allowedto move to a next level of optimization and the introduction of new processes in various areas of industry. At thestage of pilot production, which is characterized by frequent changes in design, the problem of the rapidproduction of cast components becomes crucial. This is mainly due to the complexity and the complexity ofmanufacturing foundry equipment. In turn, the research and development of rapid prototyping technologies haveallowed a new level of optimization and the introduction of new technologies in the investment casting. The aimof this work is to identify opportunities and evaluate accuracy of the size of the casting during investment castingusing rapid prototyping technology. The work was conducted with the use of cross-cutting design in CAM/CAD/CAE systems. The study size and precision parameters of the casting was conducted in coordinatemeasuring machine. The work has been verified the adequacy of the virtual simulation of the process of forminga casting in the casting simulation ProCAST, in comparison with those obtained castings. The study showed thatthe use of rapid prototyping technologies with investment casting can significantly reduce the time for makingcastings, reduce production costs and improve the accuracy of the size of the casting.

Research of machinability of heat resistant steels 10Х11НN23T3MР-ВД used in parts of gas turbine engines

In article questions the workability of heat-resistant chromium-nickel steel 10Х11Н23Т3МР-ВД are considered. To investigate the machinability of heat-resistant material used modern milling machines, CNC torque table Kistler, modern monolithic milling tool company Seco, in the form of the mandrel used termic clamping provides the highest rigidity fixing. Posed a series of experiments to measure the cutting forces that arise during processing. For the experiment were selected workpiece in the form of plates. The surface of each sample is pretreated so that the initial surface roughness for all samples was the same Ra 1,25. Materials blanks: Steel ЭП33 ВД (10Х11Н23Т3МР-ВД). As a cutting tool in the model used milling company Seco. The analysis and processing of the experimental results are provided. According to experimental data are constructed dependences of the cutting force on the speed, depth of cut and feed. Depending obtained using neural network models, linking cutting forces with the technological parameters.It is established that the neural network model provides a more accurate prediction of cutting forces, especially in the field of higher cutting speeds. Since the full-scale testing was costly for the purchase of an experienced tool and workpiece, the cutting process was modeled with the given experimental conditions for comparison of experimental data and modeling. For this purpose, it was used a virtual simulation of the machining in the environment DEFORM 3D.

Theoretical and experimental stress - strain analysis of machining gas turbine engine parts, which made of the high energy structural efficiency alloys

Methods to improve accuracy of the gas turbine engine (GTE) blades machining by analyzing the stress-strain state were reviewed. The new method to compensate for machining error was proposed. The model of parameters that affect cutting mode and the radial component of cutting force during milling was developed.

Improving fatigue strength by producing residual stresses on surface of parts of gas-turbine engines using processing treatments

The paper deals with a comparison of results of measuring residual stresses and with the study of their effect on the fatigue strength of parts of gas-turbine engines after finish treatments by grinding, polishing, and surface plastic deformation.

Carbon materials for parts of gas-turbine engines and internal combustion engines, problems and prospects

The paper presents the results of application of carbon-containing material "KARBUL" for manufacturing for internal combustion engine pistons, the technology of piston manufacturing of material "KARBUL". The authors describe the prospects for use of "KARBUL" material for small-size gas turbine engines.

HEAT AND EROSION-RESISTANT NANOSTRUCTURED COATINGS FOR GAS TURBINE ENGINES

This work analyses the characteristics of functional coatings obtained by vacuum ion-plasma sputtering. These coatings have three-layer multiphase structure created as a result of condensing aluminium and titanium according to a certain programme. The article presents the results of investigation into the heat-resistance of ion-plasma coatings based on Ti-Al-N for titanium alloy parts of gas turbine engines. Analysis of the oxidation process between a sample surface and coatings within the range of 500–825 °C was carried out. The basic features of the process of coating destruction under high-temperature oxidation conditions were determined by means of scanning electron microscopy. The results of the tests made it possible to state that the coatings developed are able to operate at temperatures of 600–750 °C.

Ni 基超合金 Inconel 718 の固相線温度近傍における力学特性値の引張速度依存性

Nickel-based superalloys have been applied to gas turbine and aircraft jet engine parts due to superior high temperature strength and corrosion resistance. However, casting defect such as solidification cracking often occurs. In order to increase productivity of precision casting and various shape casting processes, predicting the occurrence of solidification cracking by using CAE (Computer Aided Engineering) should be essential. Therefore, it is necessary to obtain mechanical properties in the state of solid-liquid coexistence. In the previous reports, high temperature mechanical properties were examined but tensile rate dependency wasn't examined. In this study, high temperature (around solidus temperature) mechanical properties and tensile rate dependency of their alloy were examined by using originally developed tensile test.

Analysis of measuring errors and an object in determining residual stresses

The article is devoted to the identification of errors meter and an object in determining residual stresses in parts of gas turbine engines. Moreover, analysis of influence of the state of the surface of the measured residual stresses is made.

Possibility to regenerate parts of ship gas turbine engines using the plasma metallization process

This paper presents the regeneration of parts of ship gas turbine engines by the plasma metallization process. One of the most modern metallization procedures is a plasma process, which has more advantages compared to other metallization procedures. This work will deal with metallization processes, i.e. the plasma-based metallization process and the possibility of applying this process to the regeneration of parts of ship gas turbine engines (GTEs).

Ni基超合金Inconel 718の固相線温度近傍における力学特性取得に関する検討

Nickel-based superalloys have been applied to gas turbine and aircraft jet engine parts due to superior high temperature strength and corrosion resistance. However, casting defect such as solidification cracking often occurs. In order to increase productivity of precision casting and various shape casting processes, predicting the occurrence of solidification cracking by using CAE(Computer Aided Engineering) should be essential. Therefore, it is necessary to obtain mechanical properties in the state of solid-liquid coexistence. In this study, we try to get high temperature (around solidus temperature) mechanical properties of the nickel-based superalloy such as Inconel 718 by using originally developed tensile test. In the previous reports, flat distribution of temperature in the gage length, and crack initiation strain were not ensured. On the other, the developed device ensured within 3℃ of the temperature distribution in the gage length as to the Inconel 718. Tensile strain was measured by using in-situ observation of marker on the surface of the specimen. As a result, Stress-Strain curve, crack initiation stress, and crack initiation strain of Inconel 718 were obtained.

Fracture toughness analysis of specimens from granular alloy ÉP741NP under conditions of low-cycle fatigue using the finite element method

The possibilities of applying the procedures for calculating the fracture toughness in terms of the finite element method and fracture mechanics relationships are analyzed based on the experimental data obtained in low-cycle fatigue tests of specimens. The influence of defects available in the granular material on the life of specimens is estimated. Good agreement is obtained between the calculated results and the experimental ones, which has validated the applicability of the above computational procedures, as well as the possibility of their use for fracture toughness analysis and life prediction of real gas turbine engine parts. The peculiarities of the granular material fracture behavior revealed during this investigation can be taken into account in the mechanical design of new products of aircraft engineering.