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Various techniques for manufacturing integrally bladed turbine disks (turbine blisks) are described, followed by a discussion of the development trend of turbine blisk manufacture. Analysis shows that powder metallurgy near‐net‐shape hot isostatic pressing will be the focus of future research for turbine blisk blanking, while electrical discharge machining still will be the most competitive technology for turbine blisk finishing.

The aviation industry has seen consistent growth over the past few decades. To maintain its sustainability and competitiveness, it is important to have a comprehensive understanding of the environmental impacts across the entire life cycle of the industry, including materials, processes and resources; manufacturing and production; lifetime services; reuse; end-of-life; and recycling. One important component of aircraft engines, integral rotors known as Blisks, are made of high-value metallic alloys that require complex and resource-intensive manufacturing processes. The purpose of this paper is to assess the ecological and economical impacts generated through Blisk production and thereby identify significant ‘hot-spots’.

This paper focuses on the methodology and approach for conducting a full-scale Blisk life cycle assessment (LCA) based on ISO 14040/44. Unlike previous papers in the European Aerospace Science Network series, which focused on the first two stages of LCA, this publication delves into the “life cycle impact assessment” and “interpretation” stages, providing an overview of the life cycle inventory modeling, impact category selection and presenting preliminary LCA results for the Blisk manufacturing process chain.

The result shows that the milled titanium Blisk has a lower CO₂ footprint than the milled nickel Blisk, which is less than half of the global warming potential (GWP) of the milled nickel Blisk. A main contributor to GWP arises from raw material production. However, no recycling scenarios were included in the analysis, which will be the topic of further investigations.

The originality of this work lies in the detailed ecological assessment of the manufacturing for complex engine components and the derivation of hot spots as well as potential improvements in terms of eco-footprint reduction throughout the products cradle-to-gate cycle. The LCA results serve as a basis for future approaches of process chain optimisation, use of “greener” materials and individual process improvements.

It is very important to create a useful cyclic symmetric model for the investigation of the vibration reduction effect of hard-coating blisk. This study aims to develop a cyclic symmetry algorithm which can determine the mode of blisk in the sector coordinate system directly.

Using the exponential and real quasi-equivalent Fourier matrices, the formulas for solving the sector mode were derived, and the relationship between the two kinds of sector modes was also discussed. Based on the proposed cyclic symmetry algorithm, the vibration characteristics of an academic blisk were solved, and the formulas for solving the natural characteristics and vibration responses of the coated blisk were given.

A blisk with NiCrAlCoY+YSZ hard coating on both sides of each blade was chosen as a case to demonstrate the presented method. Based on the verification analysis model, the influences of coating thickness on the vibration reduction effect of the blisk were discussed. The results show that the hard coating has good vibration reduction effect on the blisk even the coating thickness is very thin and the vibration reduction effect of hard coating in the high frequency range is obviously better than that in the low frequency range.

As a large number of reduced order modeling methods of blisk are implemented based on the sector modes, the proposed method which can obtain the sector modes directly will significantly improve the efficiency of dynamic modeling and analysis of the coated blisk structure.

Turbine blisks designed for advanced liquid rocket engine turbopumps are usually of a timed structure with twisted blades, and they can be machined effectively with the electrical discharge machining (EDM) process. After the machining specifications have been designated, the EDM process of a turbopump turbine blisk is discussed, in which the kernel problems are the design of the electrode and the searching of an interference free path to feed the electrode to machine the blisk.

This study aims to propose a novel configuration for turbofan engine inlets to increase the overall effectiveness of the engine.

Conventional fan has been split radially into two blisk stages, namely, core blisk and bypass blisk. The two blisks are driven by a common shaft but rotate at two different revolutions per minutes (RPMs) on the same plane of rotation simultaneously through a planetary gear mechanism. To avoid any mechanical contact between the two stages, a minimum optimum distance is kept between them.

An apt reduction ratio of planetary gears allows the bypass blisk to rotate at a lower RPM. Thus, unlike conventional geared single fan configuration, transonic speed at the blade’s tip is prevented without decreasing the core stage’s RPM. Consequently, wave drag is eradicated without compromising the engine's core performance as surplus air can always be supplied to it. Compressor stall and surge can also be significantly reduced.

The concept is at its infancy. Extensive iterations and experimentations are required before implementing it practically.

The configuration fulfils to conceive a practical and industrially scalable method to extract better performance from existing engine architecture with minimal changes while reducing noise and emissions, meeting the short-term emission and noise goals unless electric or hydrogen-powered flight fully matured.

The present concept reduces engine noise and thereby helps in reduction of airport noise pollution. This concept also helps in reducing global warming by reducing emissions.

The paper presents a novel configuration for a turbofan engine’s inlet fan and discusses its engineering implications and initial feasibility in detail.

The purpose of this study is analysis of deformation and vibrations of turbine blades produced by high electrolyte pressure during electrochemical machining.

An experimental setup was designed, experiments were conducted and the obtained results were compared with the finite element results. The deformations were measured according to various flow rates of electrolyte. In finite element calculations, the pressure distribution created by the electrolyte on the blade surface was obtained in the ANSYS® (A finite element analysis software) Fluent software and transferred to the static structural where the deformation analysis was carried out. Three different parameters were examined, namely blade thickness, blade material and electrolyte pressure on blade disk caused by mass flow rate. The deformation results were compared with the gap distances between cathode and anode.

Large deformations were obtained at the free end of the blade and the most curved part of it. The appropriate pressure values for the electrolyte to be used in the production of blisk blades were proposed numerically. It has been determined that high pressure applications are not suitable for gap distance lower than 0.5 mm.

When the literature is examined, it is required that the high speed flow of the electrolyte is desired in order to remove the parts that are separated from the anode from the machining area during electrochemical machining. However, the electrolyte flowing at high speeds causes high pressure in the blisk blades, excessive deformation and vibration of the machined part, and as a result, contact of the anode with the cathode. This study provides important findings for smooth electro chemical machining at high electrolyte flows.

The purpose of this paper is to briefly summarize and review the theories and methods of complex structures’ dynamic reliability. Complex structures are usually assembled from multiple components and subjected to time-varying loads of aerodynamic, structural, thermal and other physical fields; its reliability analysis is of great significance to ensure the safe operation of large-scale equipment such as aviation and machinery.

In this paper for the single-objective dynamic reliability analysis of complex structures, the calculation can be categorized into Monte Carlo (MC), outcrossing rate, envelope functions and extreme value methods. The series-parallel and expansion methods, multi-extremum surrogate models and decomposed-coordinated surrogate models are summarized for the multiobjective dynamic reliability analysis of complex structures.

The numerical complex compound function and turbine blisk are used as examples to illustrate the performance of single-objective and multiobjective dynamic reliability analysis methods. Then the future development direction of dynamic reliability analysis of complex structures is prospected.

The paper provides a useful reference for further theoretical research and engineering application.

TWO more EJ200 flight engines for the Eurofighter 2000 were handed over recently