Explore the vast range of titles available.

A comprehensive reference for engineers and researchers, this second edition focuses on gas turbine heat transfer issues and their associated cooling technologies for aircraft and land-based gas turbines. It provides information on state-of-the-art cooling technologies such as advanced turbine blade film cooling and internal cooling schemes.

Developing clean, sustainable energy systems is a pre-eminent issue of our time. Most projections indicate that combustion-based energy conversion systems will continue to be the predominant approach for the majority of our energy usage. Unsteady combustor issues present the key challenge associated with the development of clean, high-efficiency combustion systems such as those used for power generation, heating or propulsion applications. This comprehensive study is unique, treating the subject in a systematic manner. Although this book focuses on unsteady combusting flows, it places particular emphasis on the system dynamics that occur at the intersection of the combustion, fluid mechanics and acoustic disciplines. Individuals with a background in fluid mechanics and combustion will find this book to be an incomparable study that synthesises these fields into a coherent understanding of the intrinsically unsteady processes in combustors.

Emissions from the transportation sector are significant contributors to climate change and health problems because of the common use of gasoline vehicles. Countries in the world are attempting to transition away from gasoline vehicles and to electric vehicles (EVs), in order to reduce emissions. However, there are several practical limitations with EVs, one of which is the “range anxiety” issue, due to the lack of charging infrastructure, the high cost of long-ranged EVs, and the limited range of affordable EVs. One potential solution to the range anxiety problem is the use of range extenders, to extend the driving range of EVs while optimizing the costs and performance of the vehicles. This paper provides a comprehensive review of different types of EV range extending technologies, including internal combustion engines, free-piston linear generators, fuel cells, micro gas turbines, and zinc-air batteries, outlining their definitions, working mechanisms, and some recent developments of each range extending technology. A comparison between the different technologies, highlighting the advantages and disadvantages of each, is also presented to help address future research needs. Since EVs will be a significant part of the automotive industry future, range extenders will be an important concept to be explored to provide a cost-effective, reliable, efficient, and dynamic solution to combat the range anxiety issue that consumers currently have.

Single crystal Ni-based superalloys have long been an essential material for gas turbines in aero engines and power plants due to their outstanding high temperature creep, fatigue and oxidation resistance. A turning point was the addition of only 3 wt.% Re in the second generation of single crystal Ni-based superalloys which almost doubled the creep lifetime. Despite the significance of this improvement, the mechanisms underlying the so-called “Re effect” have remained controversial. Here, we provide direct evidence of Re enrichment to crystalline defects formed during creep deformation, using combined transmission electron microscopy, atom probe tomography and phase field modelling. We reveal that Re enriches to partial dislocations and imposes a drag effect on dislocation movement, thus reducing the creep strain rate and thereby improving creep properties. These insights can guide design of better superalloys, a quest which is key to reducing CO 2 emissions in air-traffic. Adding minute amounts of rhenium to Ni-based single crystal superalloys extends their high temperature performance in engines, but the reasons behind that are still unclear. Here, the authors combine high resolution imaging and modelling to show that rhenium enriches and slows down partial dislocations to improve creep performance.

The article reviews gas turbine combustion technologies focusing on their current ability to operate with hydrogen enriched natural gas up to 100% H2. The aim is to provide a picture of the most promising fuel-flexible and clean combustion technologies, the object of current research and development. The use of hydrogen in the gas turbine power generation sector is initially motivated, highlighting both its decarbonisation and electric grid stability objectives; moreover, the state-of-the-art of hydrogen-blend gas turbines and their 2024 and 2030 targets are reported in terms of some key performance indicators. Then, the changes in combustion characteristics due to the hydrogen enrichment of natural gas blends are briefly described, from their enhanced reactivity to their pollutant emissions. Finally, gas turbine combustion strategies, both already commercially available (mostly based on aerodynamic flame stabilisation, self-ignition, and staging) or still under development (like the micro-mixing and the exhaust gas recirculation concepts), are described.

A recently introduced NURBS mesh generation method for complex-geometry Isogeometric Analysis (IGA) is applied to building a high-quality mesh for a gas turbine. The compressible flow in the turbine is computed using the IGA and a stabilized method with improved discontinuity-capturing, weakly-enforced no-slip boundary-condition, and sliding-interface operators. The IGA results are compared with the results from the stabilized finite element simulation to reveal superior performance of the NURBS-based approach. Free-vibration analysis of the turbine rotor using the structural mechanics NURBS mesh is also carried out and shows that the NURBS mesh generation method can be used also in structural mechanics analysis. With the flow field from the NURBS-based turbine flow simulation, the Courant number is computed based on the NURBS mesh local length scale in the flow direction to show some of the other positive features of the mesh generation framework. The work presented further advances the IGA as a fully-integrated and robust design-to-analysis framework, and the IGA-based complex-geometry flow computation with moving boundaries and interfaces represents the first of its kind for compressible flows.

YSZ has been widely used as a TBC material, but its phase change at high temperatures limits its development, thus the need for developing new thermal barrier materials resistant to high temperatures. Rare-earth aluminate ceramics with a garnet structure (Yb[sub.3]Al[sub.5]O[sub.12]) have been considered as a potential thermal barrier material. The melting point of Yb[sub.3]Al[sub.5]O[sub.12] is 2000 °C, which has a potential high temperature application prospect. However, Yb[sub.3]Al[sub.5]O[sub.12] has lower thermal expansion and higher thermal conductivity than YSZ, which is a widely employed thermal barrier coating (TBC) material. To overcome these obstacles, (Y[sub.0.2]Dy[sub.0.2]Ho[sub.0.2]Er[sub.0.2]Yb[sub.0.2])[sub.3]Al[sub.5]O[sub.12], a high-entropy ceramic, was prepared by a solid-state reaction and pressureless sintering. The thermal conductivity of the (Y[sub.0.2]Dy[sub.0.2]Ho[sub.0.2]Er[sub.0.2]Yb[sub.0.2])[sub.3]Al[sub.5]O[sub.12] was 3.48 W/(m·K) at 300 K, approximately 25.48% lower than that of the Yb3Al5O12 (4.67 W/(m·K)). The thermal expansion coefficient of the (Y[sub.0.2]Dy[sub.0.2]Ho[sub.0.2]Er[sub.0.2]Yb[sub.0.2])[sub.3]Al[sub.5]O[sub.12] was 9.28 × 10[sup.−6] K[sup.−1] at 673-1273 K, approximately 18.52% higher than that of the Yb[sub.3]Al[sub.5]O[sub.12] (7.83 × 10[sup.−6] K[sup.−1], 673-1273 K). When the (Y[sub.0.2]Dy[sub.0.2]Ho[sub.0.2]Er[sub.0.2]Yb[sub.0.2])[sub.3]Al[sub.5]O[sub.12] was annealed at 1550 °C for 7 days, its average grain size only increased from 0.7 μm to 1.3 μm. Moreover, the (Y[sub.0.2]Dy[sub.0.2]Ho[sub.0.2]Er[sub.0.2]Yb[sub.0.2])[sub.3]Al[sub.5]O[sub.12] exhibited better chemical stability and a lower grain growth rate than the Yb[sub.3]Al[sub.5]O[sub.12]. This study reveals that (Y[sub.0.2]Dy[sub.0.2]Ho[sub.0.2]Er[sub.0.2]Yb[sub.0.2])[sub.3]Al[sub.5]O[sub.12] is a promising candidate for the future generation of thermal barrier materials.

Silicon nitride ceramics excel by superior mechanical, thermal, and chemical properties that render the material suitable for applications in several technologically challenging fields. In addition to high temperature, high stress applications have been implemented in aerospace gas turbines and internal combustion engines as well as in tools for metal manufacturing, forming, and machining. During the past few decades, extensive research has been performed to make silicon nitride suitable for use in a variety of biomedical applications. This contribution discusses the structure–property–application relations of silicon nitride. A comparison with traditional oxide-based ceramics confirms that the advantageous mechanical and biomedical properties of silicon nitride are based on a high proportion of covalent bonds. The present biomedical applications are reviewed here, which include intervertebral spacers, orthopedic and dental implants, antibacterial and antiviral applications, and photonic parts for medical diagnostics.

This article reviews the critical role of material selection and design in ensuring efficient performance and safe operation of gas turbine engines fuelled by ammonia–hydrogen. As these energy fuels present unique combustion characteristics in turbine combustors, the identification of suitable materials becomes imperative. Detailed material characterisation is indispensable for discerning defects and degradation routes in turbine components, thereby illuminating avenues for improvement. With elevated turbine inlet temperatures, there is an augmented susceptibility to thermal degradation and mechanical shortcomings, especially in the high-pressure turbine blade—a critical life-determining component. This review highlights challenges in turbine design for ammonia–hydrogen fuels, addressing concerns like ammonia corrosion, hydrogen embrittlement, and stress corrosion cracking. To ensure engine safety and efficacy, this article advocates for leveraging advanced analytical techniques in both material development and risk evaluation, emphasising the interplay among technological progress, equipment specifications, operational criteria, and analysis methods.

The objective of this paper is to designed a nonuniform arrangement of elliptical holes for film cooling (FICO) on gas turbine blades. The optimal distance between rows of holes (1–3) was determined to maximize FICO effectiveness. The three-dimensional geometry of the problem (Circle, horizontal elliptic, and vertical elliptic) was modeled based on an existing experimental sample. The turbulent steady-state incompressible single-phase flow was modeled using conservation equations and considering the blowing ratio (0.25–2), adiabatic FICO efficiency, von Mises stress (VMS), and hydraulic radius relationships. Results showed that elliptical holes with a major diameter normal to the flow had the highest centerline and laterally averaged effectiveness values. Additionally, holes that were more laterally stretched out had higher efficiency. The best effectiveness was achieved at an optimal blowing ratio of 0.75. Furthermore, the maximum von Mises stress was higher in cases with smaller distances between rows. Von Mises stress analysis revealed that elliptical openings with a large diameter perpendicular to the flow caused the lowest thermal stress in the solid body. When cooling with three rows of elliptical holes, a larger distance between the second and third rows resulted in higher effectiveness and lower maximum VMS at an optimal distance.