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![Fundamental arrangements for epicyclic gear systems a) Star system b) Planet system (adapted from [27]).](profile/Roberto-Sabatini-3/publication/335196845/figure/fig3/AS:799779391041549@1567693674982/Fundamental-arrangements-for-epicyclic-gear-systems-a-Star-system-b-Planet-system.png)
Fundamental arrangements for epicyclic gear systems a) Star system b) Planet system (adapted from [27]).
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![Fig. 3. Optimization of fan diameter for the CFM LEAP-1B [19].](profile/Roberto-Sabatini-3/publication/335196845/figure/fig2/AS:799779391016973@1567693674951/Optimization-of-fan-diameter-for-the-CFM-LEAP-1B-19_Q320.jpg)
![Fig. 5. Unique FDGS lubrication system (adapted from [27]).](profile/Roberto-Sabatini-3/publication/335196845/figure/fig4/AS:799779395219456@1567693675016/Unique-FDGS-lubrication-system-adapted-from-27_Q320.jpg)
Turbofan engines are the most widely used propulsion technology in commercial transport aircraft and are directly involved in many of the environmental impacts of aviation. Advancements in turbofan technology have thus a significant potential in reducing aviation impacts on the environment. This article reviews the main technological advances curre...
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Citations
... The energy utilization calculation with ISM melting was achieved by volume fraction calculations of each component eddy current loss, as shown in Eq. (1). Therefore, comparison of the charge energy utilization in different crucible and coil structures could be done by modelling the EM field. ...
Induction skull melting (ISM) technology could melt metals with avoiding contamination from crucible. A long-standing problem of ISM is that the low charge energy utilization and inhomogeneous fields have obstructed its application in many critical metal materials and manufacturing processes. The present work investigated the problem through the structure optimization strategy and established a numerical electromagnetic-field model to evaluate components’ eddy current loss. Based on the model, the effect of crucible and inductor structure on charge energy utilization, etc. was studied. Furtherly, the charge energy utilization was increased from 27.1 to 45.89% by adjusting the system structure. Moreover, structure modifications are proposed for enhancing electromagnetic intensity and uniformity, charge soft contact and uniform heating. The work constructed a basis for framing new solutions to the problem through ISM device structure optimization.
... The suggested technique is important because it solves the complicated problem while also making it simple to evaluate the design and monitor the performance criteria. The results demonstrated that wide-body aircraft are useful for long-distance travel since they have greater fuel efficiency, retrofit passenger comfort, lower TSFC through better aerodynamics configurations [19,20]. This study found that advanced composite materials and cut the unwanted volume of the aircraft can have an impact on fuel efficiency. ...
... One of the current priorities of the aviation industry is sustainability. Currently, the main propulsion system for commercial aircraft are turbofan engines, and they are directly involved in many of the environmental impacts caused by aviation (Ranasinghe et al., 2019). This type of engine produces several environmentally harmful emissions. ...
Aviation is undergoing a paradigm shift to become a more sustainable industry. Priorities include reducing fossil fuel consumption, cutting carbon dioxide and other emissions, and developing new technologies. One of the major enabling technologies is the electrification of aircraft. Batteries are a key part of this revolutionary concept. This paper aims to provide key insights into battery technology and its potential to electrify aviation. Therefore, it proposes a comprehensive presentation of this technology following a detailed research process. Five different topics are addressed. The first is a general overview of the chemistry of electrochemical cells, the basic element of batteries. This is followed by a presentation of some of the most relevant previous work in this topic, highlighting their contributions and their main outcomes to be considered in further research. The main performance metrics used to compare the different batteries are presented next. For each of them, the definition, and related requirements that batteries used in electric aviation must meet are included. The paper then analyzes the possibilities for battery use in aviation and identifies some key challenges that need to be overcome to scale-up this technology. Finally, some battery technologies, their current uses, and their potential for further progress toward a more sustainable aviation are presented in detail.
... Compressed air reaches the chamber where it is mixed with fuel, then ignited in an expander in which work is generated and heat released to the surroundings. This sequence forms two isentropic processes (compression and expansion) and two isobaric (heat and work) (Cengel and Boles, 2008) (Bugge et al., 2006) (Ranasinghe et al., 2019). Figure 2 shows the Brayton T-S diagram. ...
... Ideal Brayton cycle.(Ranasinghe et al., 2019) ...
Adopting renewable energy sources to the detriment of non-renewable energy matrices is a change in progress worldwide. This movement is in concordance with the mutual necessity to reduce the emission of greenhouse gases and decelerate the impacts of global warming. Green hydrogen has been pointed out as a sustainable energy alternative since it is a product from renewable energy sources and its production process is carbon-free. This work proposes a comprehensive review of the main methods to produce green hydrogen derived from solar thermal energy. The presented review mentions thermodynamic cycles concepts and the more quoted models regarding sustainability according to the literature. The qualitative analysis foresees parameters like the working fluid, energetic efficiency, the project's production level, and performance. Considering the information presented, the organic Rankine cycle (ORC) is the most suitable cycle to elaborate a viable large-scale project, owing to the possibility of functioning with lower temperatures in the heat source. Brayton and Rankine cycles are indicated for intermediate and higher temperatures. This detailed revision of the proposed productive methods powered by solar thermal energy expects to guide future projects to describe a more insightful and profound proposition for an ideal plant.
... In regard to CFD, the scale-resolving Large Eddy Simulation (LES) approach has proven to be an efficient and accurate method for the simulation of reacting flows in the context of gas turbine combustion [24]. By using GTP-23-1287 5 Hoffmann the turbulent flamelet model [25] or the Flamelet-Generated Manifold (FGM) approach [26,27] combined with a presumed Probability Density Function (PDF) closure method to describe turbulence-chemistry interaction, the overall reactivity of the low-swirl lifted flame was overpredicted, giving smaller lift-off heights compared to the experimental findings. In contrast, the Thickened Flame (TF) model slightly overestimated the position of the main reaction zone by using a global two-step reaction mechanism [28]. ...
By tilting the burners of an annular aeronautical combustor in circumferential direction, the potential of increased combustion stability is opened up due to an enhanced exhaust gas recirculation between adjacent flames. The innovative gas turbine combustor concept, called the Short Helical Combustor (SHC), allows the main reaction zone to be operated at low equivalence ratios. A lean lifted flame is implemented in the staggered SHC burner arrangement. The objective is to reach ultra-low NOx emissions by extensive premixing of fuel and air upstream of the lean reaction zone. In the present work, a modeling approach is developed to investigate the characteristics of the lifted flame, using the gaseous fuel methane. It is demonstrated that by using the Large Eddy Simulation method, the shape and lift-off height of the flame is adequately reproduced by means of the finite-rate chemistry approach. For the numerical prediction of the lean lifted flame in the SHC arrangement, the focus is on the interaction of adjacent burners. It is shown that the swirling jet flow is deflected towards the sidewall of the staggered combustor dome, which is attributed to the asymmetrical confinement. Since the stabilization mechanism of the low-swirl flame relies on outer recirculation zones, the upstream transport of hot combustion products back to the flame base is studied by the variation of the combustor confinement ratio. It turns out that increasing the combustor size amplifies the exhaust gas recirculation along the sidewall, and increases the temperature of recirculating burned gases.
... It accounts for roughly 12 % of the aviation transportation industry's carbon dioxide (CO 2 ) emissions [3,4]. In recent years, numerous studies have been conducted on the impact of air traffic on the atmosphere [5].Compared to the amount of time that people spend on aircraft, the environmental footprint of air travel is massive. Despite widespread environmental concern and widespread social acceptance of the need to combat global climate change, air travel is expanding rapidly [6]. ...
It is a matter of great concern that the aviation industry, which has made significant contributions to the transportation sector, relies heavily on nonrenewable fossil fuels that are causing substantial pollution, leading to the industry's unsustainability. To address this issue, the industry has shifted its focus towards sustainable aviation fuels, with hydrogen fuel showing great promise due to its clean and eco-friendly nature. However, the adoption of hydrogen as an energy carrier in aviation presents several challenges, including the lack of a supply chain comparable to that of kerosene, which is currently the primary fuel used in aviation. The supply chain for hydrogen involves various sub-sections such as production, liquefaction, transport, storage, and distribution. This study aims to analyze the hydrogen supply chains for airports and to develop scenarios for its implementation. The study evaluates the environmental impact, cost, sustainability, viability, and safety in different supply chain scenarios, as well as recommending a comprehensive approach to supply chain development that involves collaboration between industry, government, and academia.
... industrial robots reduce labor inputs and innovative organizational structures improve work efficiency) (4); it can save capital by introducing advanced and cheap machines and using more labor-oriented technologies (e.g. intelligent monitoring system reduces maintenance costs) (5); it can also save intermediate inputs through the discovery of new or the improvement of existing technologies that use a smaller proportion of intermediate products (e.g. nanomaterial application improves solar panel efficiency) (6). ...
Technological progress (TP) is a double-edged sword to global climate change. This study for the first time reveals rebound and mitigation effects of efficiency-related TP in global value chains (GVCs) on greenhouse gas (GHG) emissions. The integrated effects of TP depend on the positioning of sectors in GVCs. The cost-saving TP in upstream sectors would stimulate downstream demand. This produces stronger rebound effects than mitigation potentials and leads to global GHG emission increments (e.g. TP in the gas sector of China and petroleum and coal products sector of South Korea). In contrast, sectors located in the trailing end of GVCs have greater potentials for GHG emission mitigation through TP, mainly due to the reduction of upstream inputs. (e.g. the construction sector of China and dwelling sector of the United States). Global GHG emissions and production outputs can be either a trade-off or a win–win relationship on account of TP than rebound effects, because TP in different sectors could possibly increase or decrease the emission intensity of GVCs. This study could recognize the most productive spots for GHG emission mitigation through efficiency-related TP. It provides a new perspective for international cooperation to promote global GHG emission mitigation.
... These defects could appear as wear when the rolling elements' raceways develop a recess, cracking, and abrasives because of overloading and inadequate lubrication. The corrosion caused by the pitting of the raceways and the bearing surface, together with the inclusion of moisture between the load bearing sections, causes crack propagation [3,4]. One of the most common causes of rolling bearing failure is chipping from the raceways or rolling elements. ...
Bearings are the significant components among the rolling machine elements subjected to high wear and tear. The timely detection of faults in such components rotating at higher frequencies can save substantial maintenance costs and production setbacks. Physical examination and fault detection by human experts is always challenging at runtime. Predictive maintenance and real-time condition monitoring are gaining higher utility with the advent of suitable instrumentation and machine learning classifiers. A convolutional neural network (CNN) based bearing fault detection scheme is developed in this research work. The acquired sensory data of vibration signals are converted into the frequency domain and then fed to the classifier for spectral feature extraction and fault classification. The CNN architecture is trained and tested using a bearing dataset available online. The model is further tested and validated with the data acquired from an indigenously designed bearing test rig. The proposed scheme has successfully detected inner and outer race faults and no fault or normal state. This multiclass fault classification has shown promising results with 97.68% accuracy, 96.9% precision, 99.14% sensitivity, 98.01% F1-score, and 93.65% specificity. The achieved results validate the utility of the proposed detection system. Hence the presented scheme has deployment potential for real-time condition monitoring and predictive maintenance applications.
... Because of the stringent restrictions on emissions by current environmental regulations, the lean premixed combustion, with the advantages of low NO x emissions and high combustion efficiency, has been favored by both ground gas turbines and aeroengines [1][2][3] . However, lean combustion systems are more prone to self-sustained combustion instabilities as they usually operate near the lean blowout limits [4][5] . ...
Combustion instabilities have been a plaguing challenge in lean-conditioned propulsion systems. An open-loop control system was developed using machine learning to suppress pressure fluctuations and NO x emissions simultaneously. The open-loop control is realized by regulating the solenoid valve to modulate the methane supply. Control laws comprising the multi-frequency forcing are generated via the linear genetic programming (LGP), before being converted into square waves with different frequencies and duty cycles to activate the solenoid valve. The cost function is intended to evaluate and rank individuals of each generation, so as to select candidates for evolution. Optimized periodic forcing (OPF) with different duty cycles (d) and frequencies (f P) is set to provide a comparison with the superiority of multi-frequency forcing of LGP. Three stages of pressure oscillations and NO x emissions have been found as d increases from 0.5 to 1.0: high level, transition, and low level, revealing the transition of the combustion mode. After ten generations of development, the pressure amplitude and NO x emissions are reduced by 67.1% and 36.9% under the optimal control law identified by LGP, respectively. The flame structure images and Rayleigh index maps indicate that the convective movement of the flame, which may be the key factor driving combustion instabilities, can be suppressed by the optimal control law. Furthermore, the proximity graph of the similarity between control laws is introduced to depict the machine learning process, with the steepest descent lines visualizing its ridgeline topology. With the evolution process, individuals are found moving closer to the top right-hand corner of the map, and two main search pathways gradually become clear.
... Presently, the aircraft manufacturers urge on advanced technology, the safety of passengers, maintain sustainable flight and lowering the operating cost. Enhanced fuel economy not only saves the economy for the airline industry but minimizes the overall aviation industry's carbon footprint (Ranasinghe et al., 2019;Jackson, 2010). Fuel efficiency can be improved by better design and thrust output which results and enhancement of the aircraft performance and propulsive systems. ...
... According to correlation analysis, MTOW has a significant impact on fuel economy. IATA (2020) reported that upgrading engines cut down fuel consumption by 10% (Ranasinghe et al., 2019). Fuel efficiency improves by lower TSFC as shown in equation (4). ...
Purpose
This research is associated with the real-time parameters of wide- and narrow-body aircraft to recognize the quantitative relationship framework. This paper aims to find the superiority of aircraft design technology which triggers the reduction in specific fuel consumption (SFC) and economic competitiveness.
Design/methodology/approach
The real case study is performed with 22 middle-of-the-market (MoM) aircraft. This paper develops a fuel burn mathematical model for mid-size transport aircraft by a multi-linear regression approach. In addition, sensitivity analysis is performed to establish the authentication of the fuel burn model.
Findings
The study reveals that the MoM aircraft would be the future aircraft design in terms of better fuel economy and carbon footprint. From the multi-regression analysis, it is observed that the logarithmic regression model is the best fit for estimating the SFC. Moreover, fineness ratio, aspect ratio, gross weight, payload weight fraction, empty weight fraction), fuel weight fraction, payload, wing loading, thrust loading, range, take-off distance, cruise speed and rate of climb are observed as the suitable parameters which provide the best fitness value as 0.9804.
Originality/value
Several existing literature reveals that a few research has been performed on the MoM aircraft with wide-body configuration. Moreover, mathematical modelling on the fuel consumption was insignificantly found. This study examines several parameters which affect the fuel consumption of a wide-body aircraft. A real-case study for design configurations, propulsive systems, performance characteristics and structural integrity parameters of 22 different MoM aircraft are performed. Moreover, multi-regression modelling is developed to establish the relation between SFC and other critical parameters.
