Gas Turbine Engine Blades Research Articles

Aerodynamic performance evaluation of subsonic compressor cascade blade with leading-edge damage

Abstract Material loss at the leading edge of in-service gas-turbine engine blades is detrimental to the aerodynamic performances of compressors. In this study, computational simulations and experiments using pneumatic probes were conducted to measure the total pressure loss of compressor cascade blades with material loss at their leading edges. The correlations between blade leading-edge damage geometries and cascade blade total pressure losses were analyzed. The geometrical features of blade leading-edge damage that most affect the cascade blade total pressure loss were distinguished, and the influences of leading-edge damage region cross-sectional shapes on the cascade blade total pressure loss were examined. Two methods for evaluating the total pressure loss of damaged cascade blades were developed using experimental and numerical data. In the first method, an attempt is made to correlate the cascade blade total pressure loss with a characteristic parameter that is defined using scale and angle parameters of the leading-edge damage region. The second method is based on the probability distribution function as well as the critical loss boundary of the geometrical parameters of the leading-edge damage region. The results of this study provide a better understanding of the influence of damaged leading edges on compressor cascade blade aerodynamic performance and can help establish low-cost methods for the estimation of compressor performance degradation.

Improving fatigue life of a titanium alloy through coupled electromagnetic treatments

TC11 titanium alloy is widely used in the manufacture of key components such as blades of gas turbine and aero engine because of its high specific strength and good processing performance. In the case of gas turbine or aero engine, the fatigue performance of TC11 will directly determine the life of the turbine or engine, and the surface residual stress generated on the alloy during manufacturing often affects the fatigue life of the material. In this study, a new method of coupled electromagnetic treatment (CEMT) was applied to regulate the surface residual stress of the alloy after manufacturing, so as to improve the fatigue life of the TC11. The results show that after the CEMT, the residual compressive stress in the length direction and width direction increased by 63.7% and 56.0% respectively, the fatigue life of the TC11 is increased by 39.9%. The microstructure analysis shows that after CEMT, the width of fatigue striations is significantly reduced. This paper proposes that CEMT can be used as an effective method to adjust the residual stress of materials and improve the fatigue life of titanium alloys. The research is also relevant for improvement of the fatigue life of other alloy materials.

Чисельно-експериментальне дослідження високотемпературної багатоциклової втомної міцності монокристалічних лопаток газових турбін

The subject of the research is anisotropic single-crystal turbine blades of aircraft gas turbine engines (AGTE), as well as their multi-cycle fatigue strength characteristics at high temperatures. The goal of this study was to determine the endurance limit of single-crystal high-pressure turbine blades of an AGTE at high temperatures of 820°C. The objective of the study is to develop a method for calculating and experimentally investigating the characteristics of high-temperature multi-cycle fatigue strength of gas turbine blades made of single-crystal nickel heat-resistant alloys. The research methods used are: method of computer modelling, which was used to create a 3D model of a cooled high-pressure turbine blade; finite element method, which was used to determine the stress-strain state of the blade according to the selected form of resonant vibrations; strain and resonance methods, which were used to determine the fatigue strength characteristics of single-crystal turbine blades under high-temperature loading. The following results were obtained. Literary sources describing theoretical and experimental methods for determining the strength characteristics of blades under combined dynamic and high-temperature loading were analyzed. The developed special installation for testing turbine blades under conditions of temperature and dynamic (resonant) loading was described. A combined method for assessing the multi-cycle fatigue strength at high temperatures is proposed, which includes studies on full-scale turbine blades and finite element calculations. The dynamic and temperature characterization of single-crystal turbine blades selected for the study was carried out and described. Fatigue tests were performed to determine the endurance limit of the blades at a high temperature equal to T = 820 °C. Conclusions. The scientific novelty of the obtained results is as follows. A specialized experimental setup was developed to study the endurance limit of single-crystal AGTE blades under high-temperature loading. A method for combining numerical (ANSYS) and experimental (field tests) study of high-temperature multi-cycle fatigue strength of turbine blades made of single-crystal heat-resistant alloys was developed. The direction of further research is presented.

Numerical simulation of the creep of a turbine blade made of a monocrystalline alloy

The article is devoted to the creep model of a monocrystalline alloy and the development of a methodology for identifying material parameters based on the results of physical experiments. A finite element analysis of the creep of a gas turbine engine blade was performed. Creep is one of the most dangerous types of deformation in the operating conditions of turbine blades. In the process of studying the problems of assessing the strength of turbine blades of aircraft engines and power plants, special attention should be paid to the study of stress redistribution during creep. The characteristics of the crystallographic structures of modern turbine blades have a very significant influence on the progress of the crack development process during engine operation. To date, turbine blades are manufactured by the method of single-crystal casting. This type of blade material structure is characterized by orthotropic mechanical properties. This study considers the steady-state creep model of an anisotropic heat-resistant single-crystal alloy with cubic symmetry. The authors carried out a numerical simulation of the material parameters using the well-known literary creep properties of single crystals. An algorithm is described that allows you to determine some creep characteristics of single crystals. The parameters of the given ratios can be obtained after conducting direct experiments, or based on micromechanical analysis, using the example of composite materials. The authors calculated the creep constants of a typical heat-resistant monocrystalline alloy as a result of the approximation of its creep curves, which were obtained experimentally. Based on the Norton-Bailey equation and using the Maple Release 2021.0 calculation complex, a graph of the dependence of the rate of creep deformation on the level of load applied to the material was plotted, and the minimum rate of deformation and creep constants were also determined. The results of the calculations were used for finite-element simulation of creep on the example of a solid-state model of a high-pressure turbine blade. Several series of calculations were carried out on the basis of the ANSYS Workbench complex, in particular, the calculation of the elastic problem when the blade is loaded by centrifugal forces, as well as the accumulation of creep deformations at different exposure times. Graphs of the change in equivalent stresses and creep deformations as a function of time are plotted.

Formation of Workpiece–Tool Contact Zone in Belt Grinding of Blades for Gas Turbine Engines

Formation of Workpiece–Tool Contact Zone in Belt Grinding of Blades for Gas Turbine Engines

Improvement of Hydrogen-Resistant Gas Turbine Engine Blades: Single-Crystal Superalloy Manufacturing Technology.

This paper presents the results of an analysis of resistance to hydrogen embrittlement and offers solutions and technologies for manufacturing castings of components for critical applications, such as blades for gas turbine engines (GTEs). The values of the technological parameters for directional crystallization (DC) are determined, allowing the production of castings with a regular dendritic structure of the crystallization front in the range of 10 to 12 mm/min and a temperature gradient at the crystallization front in the range of 165-175 °C/cm. The technological process of making GTE blades has been improved by using a scheme for obtaining disposable models of complex profile castings with the use of 3D printing for the manufacture of ceramic molds. The ceramic mold is obtained through an environmentally friendly technology using water-based binders. Short-term tensile testing of the samples in gaseous hydrogen revealed high hydrogen resistance of the CM-88 alloy produced by directed crystallization technology: the relative elongation in hydrogen at a pressure of 30 MPa increased from 2% for the commercial alloy to 8% for the experimental single-crystal alloy.

Increased Productivity in the Superfinishing of Large Gas-Turbine Engine Blades

Increased Productivity in the Superfinishing of Large Gas-Turbine Engine Blades

A method for cleaning the surface of gas turbine engine blades from chromium, nickel, molybdenum, cobalt and tungsten oxides using reducing properties of hydrogen

A method for cleaning the surface of gas turbine engine blades from chromium, nickel, molybdenum, cobalt and tungsten oxides using reducing properties of hydrogen

Model for Calculating Stress Intensity Factors for an Inclined Crack at the Leading Edge of a Gas Turbine Engine Blade Under the Influence of Centrifugal Forces

The study is devoted to the issue of the destruction of a body with an inclined crack during rotation. A mathematical model for calculating stress intensity factors in a rectangular plate with an inclined crack under the influence of centrifugal tensile forces during rotation around an axis lying in the plane of the plate is constructed in the article. Based on the equations of the theory of elasticity and the principles of brittle fracture mechanics, relationships were obtained that relate the stress intensity factors of type I and II, the rotation speed and geometry of the plate, as well as the parameters of the crack: length, angle of inclination to the axis of rotation, distance from the axis of rotation to the crack. The complexity of the study is because the plate in question with an inclined crack is under the action of mass forces. Therefore, the values of the effective stresses are not the same along the crack edge. Accordingly, stress intensity factors will depend on the location of the crack relative to the axis of rotation. The influence of the crack location and plate rotation speed on the change in stress intensity factor values is analyzed based on the results obtained. As the distance from the axis of rotation to the crack increases, the values of the stress intensity factors decrease. As the plate rotation frequency increases, the stress intensity coefficients increase according to a parabolic law. The results of the study can be used to assess the limit state of the rotating blades of a gas turbine engine in the presence of an inclined crack. The mathematical model can find practical application for assessing the critical speed regime of blade rotation in the presence of cracks of various lengths and angles of inclination to the rotation axis.

Application of ultrasonic fatigue technology in very-high-cycle fatigue testing of aviation gas turbine engine blade materials: A review

Application of ultrasonic fatigue technology in very-high-cycle fatigue testing of aviation gas turbine engine blade materials: A review

Approximation of the Profile of Gas Turbine Engine Blades

Introduction. Increasing the durability of gas turbine engine (GTE) blades is achieved through the use of special protective coatings on their surface. For the development of such coatings, the basic source information is the geometric profile of the blade section. To transfer a given blade cross-section profile to the appropriate CAD/CAM system or engineering analysis package, parametric modeling methods are used to automate this operation. However, the known approaches to creating a parametric model of a blade profile are not without a number of disadvantages, and a generally accepted method for creating it does not currently exist. The research was aimed at creating a technique for approximating the profile of gas turbine engine blades, convenient for use in the subsequent analysis of the operating conditions of special coatings on the surface of the blades.Materials and Methods. When constructing parametric models of the profile of gas turbine engine blades, a method based on the orthogonal Legendre polynomials was used. This made it possible to provide high accuracy of approximation and construction of a continuous mapping for the parameters of the blade profile approximation. A Python application was created for automated processing of source profiles. It provided the calculation of the coefficients of approximating polynomials for the contour lines of the blade, visualization of the calculation results, and creation of a dxf file based on the points of approximating functions to transfer it to the CAD system. Next, geometric models of blades were used to solve the problem of a stationary aerodynamic flow around a blade. The results of solving this problem were used to study the effect of the blade profile on its cooling in an aerodynamic flow.Results. As an example, three options of blade profiles belonging to different types of GTE were considered. It was shown that for all three studied profiles, the proposed technique provided obtaining parametric models that maintained high accuracy in constructing approximating lines, which was confirmed by the values of the determination coefficients close to unity. To illustrate the possibility of using the obtained models, examples of solving the gas dynamic problem with a potential flow around a blade in a stationary aerodynamic flow were given. The distributions of pressure and temperature on the surface of the blade were calculated using the finite element method.Discussion and Conclusion. The calculation results show that the proposed technique of approximating the profile of the GTE blade, based on the use of orthogonal polynomials, is a convenient tool to automate the creation of a geometric model of the blade and compare different types and profiles of blades, solving the corresponding gas dynamic problems. At the same time, for a given blade profile and GTE operating conditions, it is possible to obtain the distribution of temperatures and forces acting on the surface of the blade, which is required for predicting the durability of special coatings.

Tony F. W. Embleton in the Acoustics Section, Physics Division, of the National Research Council of Canada (NRCC)

Tony completed his PhD in three years at Imperial College (London) studying under Dr. R.W.B. Stephens. He then joined George Thiessen and Edgar Shaw at NRCC to form the core of what became arguably the most influential and productive research group in acoustics in Canada from the 1960s to the 1980s. An important activity was service to industry, a role Tony embraced by collaborating with industry associations, participating in committees and directing his research activities. Working with George Thiessen, he succeeded in reducing the noise of couch rolls, a major source of noise in paper making, by randomizing the pattern of holes through which air was sucked to dry the paper. Other successful noise control projects included staggered stator blades for gas turbine engines and mufflers for rock drills. Tony made seminal contributions to outdoor sound propagation and refined condenser microphone calibration. In addition to his research and outreach, he found time for professional service to the ASA and CAA, including serving as founding editor of what is now Canadian Acoustics, and to develop standards and mentor younger scientists, He is remembered for his cheerfulness and willingness to provide advice and engage in conversation on any and all topics.

Improving the production technology of cast billets for gas turbine engine blades

Improving the production technology of cast billets for gas turbine engine blades

Studies of turbine blades of aviation gas turbine engines during operation and heat-protective coatings for their protection

Structural changes in alloys and coatings of turbine blades of aviation gas turbine engines during their operation under the influence of high temperature and stress are considered. It is shown that the cause of the appearance of thermal fatigue cracks in the coatings of turbine blades is the discrepancy of the acting stresses on the blade to the coating parameters: aluminum content, thickness, and its strength. A heat-resistant TP for turbine blades of GTE has been developed, consisting of layers, each of which has markedly different physical, thermal, and mechanical properties, creating an essentially complex coating structure.

Study of coating efficiency of turbine blades of aircraft gas turbine engines

The purpose of the research is modern heat-resistant alloys of turbine blades, methods of cooling them, organizing their structural air cooling, and the use of heat-protective coatings.

Development of laser powder surfacing technology for aircraft gas turbine engine blades

The original technology of restoring of the working blades of the gas turbine engine using the direct material application method is developed. The technological modes of the restoring process of the geometric parameters of the parts, the consumables used are determined. The comparison of various restoring methods is carried out, the technical and economic feasibility of using this technology to restore the dimensions of parts is proved.

Application of a Ranque–Hilsch Vortex Flow in an Internal Cooling of a Gas Turbine Engine Blade

Abstract The efficiency of a gas turbine engine is directly impacted by the turbine inlet temperature and the corresponding pressure ratio. A major strategy, aside from the use of costly high-temperature blade materials, is increasing the turbine inlet temperature by internally cooling the blades using pressurized air from the engine compressor. Understanding the fluid mechanics and heat transfer of internal blade cooling is, therefore, of paramount importance for increasing the temperature threshold, hence increasing engine efficiency. This article presents modeling and test results of a novel cooling approach, one in which the Ranque–Hilsch vortex flow is adopted for the first-row gas turbine blade cooling. Simulation and test results demonstrate the successful formation of continuous Ranque–Hilsch vortex flow by injecting compressed air into a cylindrical chamber equipped with seven air inlets. At an inlet pressure of 100 kPa, the outlet temperature from the vortex tube dropped 255 °C, which allowed the blade temperature to cool by 47 °C. When a total inlet pressure of 300 kPa was admitted, the drop-in temperature reached 65 °C. The device has the potential to drop the cooling air temperature below the freezing point with increased inlet pressure. The thermal efficiency of the gas turbine blade increased by about 3% when vortex cooling with 10% mass of partially compressed air was extracted at about 910 kPa. For the tested scenario of a 17 MW power output, the partial extraction had a better efficiency increment than extraction at full compression, which was 1200 kPa.

NUMERICAL SIMULATION OF GAS-DYNAMIC AND STRENGTH CHARACTERISTICS OF A FAN FOR THE EXPERIMENTAL TEST RIG FOR INVESTIGATION OF ICE BREAKDOWN ON ROTATING WORKING BLADES

The paper is devoted to modern experimental and computational studies analysis on the point of asymmetric destruction of ice on the surfaces of the working blades of gas-turbine engine blades. A schematic diagram of an experimental setup has been developed, which consists of the following main elements: a wind tunnel, a cold chamber, a model fan, an electric motor, and a high-speed video camera. The experimental setup makes it possible to carry out laboratory studies of the ice formation and destruction processes. The choice of the experimental test rig parameters was made to allow assessing the icing of the blades of a rotating fan, which reproduces the processes occurring on gas turbine engines. Based on the results of three-dimensional gas-dynamic and strength calculations, the design and basic geometrical parameters of the flow path and the dummy fan were determined. The dependences of compression ratio Pk and the power consumption of a model fan Wcons on the value of the mass air flow Gair for a different number of rotor blades are presented. The choice of materials for the disk hub and blades of a dummy fan which experience tensile and bending loads at high rotation speeds up to 12.000 rpm was made, that satisfies the conditions of static and dynamic strength, also the allowable safety factors were evaluated, and pressure characteristics were obtained.

Development of Technology and Equipment for Producing the Hot Gas Path Blades of Gas Turbine Engines from Superalloys with a Directional and Single-Crystal Structure

Development of Technology and Equipment for Producing the Hot Gas Path Blades of Gas Turbine Engines from Superalloys with a Directional and Single-Crystal Structure

Double-Sided Deep Grinding of Gas Turbine Engine Blades with Highly Porous CBN Tools

Double-Sided Deep Grinding of Gas Turbine Engine Blades with Highly Porous CBN Tools