Advances in Sustainable Aviation

Traditionally components of aviation gasoline are produced by various technological processes. The basic fractions of aviation gasoline are straight gasoline distillation of crude oil and catalytic reforming, cracking, and blending. The main components are high-octane alkylate, technical isooctane, toluene, pirobenzol, alkylbenzene, and ethyl fluid.

The main indicator of the quality of gasoline is its antiknock rating. This ability to burn fuel without detonation of reciprocating engines with spark ignition, which is estimated octane number and describe the operational and environmental characteristics of transport.

To provide antiknock rating and high octane number for aviation fuel, add different antiknock additives. The most effective now is tetraethyl lead (TEL).

Today all the known brands of aviation gasoline used TEL as antiknock additive despite its toxicity. Therefore, development of new environmentally safe aviation gasoline is a topical modern problem that needs solving.

The alternative fuels developed recently for environmental or future economical reasons must comply with international specifications designed historically for kerosene blends. Although some of those specifications are not technically proven, they must be respected by the new fuel. This means that presently they must be mixed with Jet A-1 to be used. ONERA has started an in-house program to understand the influence of the fuel composition on the fuel behaviour and thus to widen the possible spectrum of alternative fuels. The present work describes experimental results describing ignition performances of six compositions of fuels, according to aromatics concentration, under altitude conditions, i.e. low air pressure and temperature.

The air transport industry has a significant effect on air pollution. Usage of petroleum-derived fuels is responsible for greenhouse gas emissions. Also, these fuels have a high cost. Therefore, development of alternative biofuel from renewable feedstock gains importance. Renewable and sustainable biofuels must be produced and used for the all vehicle engines. This study is related to the synthesis of biofuels and production process. Renewable feedstocks, biofuels, and their production processes are explained.

The present-day situation in civil aviation is discussed. Taking into account limitation of crude oil resources for jet fuel production and worsening of ecological situation, tendency to transition to alternative fuels is presented. Perspectives of Ukraine and Poland in production and application of alternative jet fuels are figured out. The main attention is paid to reveal possibilities of these countries for production of jet biofuels derived from plant oils. The potential of biofuel production from various feedstocks is presented and analyzed. Advantages of oil-derived biofuel production and application are discussed.

The study presents the newly developed fast three-dimensional grain burnback tool. The computational method that has been developed is based on minimum distance calculation technique. Structured grid for computational domain modeling has been used, and grid based-surface propagation method has been utilized for grain burnback simulation by using STL and SLP file formats. The developed simulation tool is able to solve very complex grain geometries. The auto mesh interface tool has been tested for quite complex grain geometries. The solution domain has been created properly without any user interference. It is observed that the determined specific distance ratio gives an acceptable accuracy within a short computation time. The burnback simulations of a real solid rocket motor indicate that the symmetrical model used with the initial distance calculation method provides an important computational time improvements. The burnback analysis of symmetrical models, initial distance calculation method, and distance calculation without sign correction methods are the originalities of the current tool. In addition, the use of SLP file format in burnback simulation and the mesh interface implementation of the developed tool significantly reduces the required total amount of user interaction for the initialization of the burnback model. This also reduces total simulation time and the error due to the user interaction.

Along with many technological and economic benefits brought by the space exploration to the humankind, there were damaging impacts of these achievements to the space environment. As a result of the activities in space, an enormous amount of uncontrolled space objects have been left in Earth’s orbit which poses a serious endangerment to the sustainability of outer space. The objective of this research was to develop an engineering method to predict an aerodynamics of arbitrary shape non-fragmenting space debris without ablation. Using a complex variable method (“linearization of single-bonded area”), a universal formula for velocity of arbitrary shape fragments was derived. This technique allows describing the space fragments (debris) of various shapes, sizes, and masses.

Results of performance calculations for a propeller-driven cargo airplane are presented for takeoff, climb, cruise, and landing flight segments. The airplane is equipped with a dual-pack engine driving a single propeller through a unique combining gearbox. It has requirements for relatively short takeoff and landing field length with unpressurized cabin at 10,000 ft (3000 m) cruising altitude. The performance analysis includes the use of engine and propeller performance models within a custom-developed computer program. It is shown in the analysis that the airplane meets takeoff, climb, and short-range cruise mission requirements.

Serpentine inlets (S-ducts) are used to supply air to the engine when it is buried in the aircraft. An intake is expected to transport the air mass flow required by the engine with minimum total pressure losses to the aerodynamic interface plane. Separation occurs inside the S-duct and generates distortion leading to instabilities. The flow structure in a diffusing S-duct is numerically investigated. Mesh dependency and different turbulence models are studied. Furthermore, it is surveyed that how the inlet profile influences the upstream flow structure. Results reveal the streamwise flow separation within the duct. Secondary flows due to spatial pressure gradient are detected. Total pressure loss is observed due to the flow structure and total pressure distortion at the AIP is calculated. Numerical results coincide well with the experimental results. Reynolds stress model is found to give the best solutions among other turbulence models.

A numerical investigation of the flow field in a short, diffusing S-duct inlet was conducted. The study was carried out in the turbulent flow where Reynolds number is 777,000, and the inlet duct had a length-to-hydraulic diameter ratio of 5.8. The primary discussion herein focuses on flow analysis and development of secondary flow in the S-duct diffuser inlet. The flow field exhibited massive flow separations and shear layer formations at both turns of the compact inlet. Moreover, secondary flow structures along the duct’s lower surface and along the duct’s side walls were identified. It was shown that the two counter-rotating flow structures along the duct’s lower surface resulted in high levels of total pressure loss at the aerodynamic interface plane. A commercial CFD code, ANSYS Fluent, is used for the simulations. In this numerical study, three different RANS turbulence models (k-e Realizable, k-w SST, and Spalart-Allmaras) were selected to capture fully turbulent flow field. Numerical results, including surface static pressure and total pressure recovery at outlet, are compared with the experimental results carried out in the literature, and fairly good agreement is apparent.

The performance of the modern aeroengines is highly dependent on the turbine inlet gas temperature. However, the turbine inlet temperatures of the today’s engines are already beyond the material structural limits. Hence, the turbine section must be cooled down to acceptable levels. Various types of cooling methods like internal cooling, film cooling, impingement cooling, etc. are typically applied to the gas turbine blades. Current research focuses on experimentally and numerically investigating the thermal performance of a two-pass channel. A rectangular cross-section tunnel with two passages and a U-turn section that mimic the modern gas turbine cooling configurations was investigated. The ribs with square cross section are located on the bottom wall of both passages. The ambient air is sucked to the wind tunnel by using a blower. The bottom wall of the test section was heated by a foil heater which generates uniform heat flux. The experiments were conducted at Reynolds number of 20,000. Finally the Nusselt number was computed based on the heater power, the surface temperature, and the mainstream temperature. The results were compared with the smooth wall configuration. Experimental results are compared with the numerical analysis to come up with a suitable turbulence model. Experimental results show that the heat transfer decays along the first pass and increases at the turning for smooth and ribbed cases. The effect of turning remains through the second passage. In terms of turbulence model performance, Rke model predicts better at the first pass; besides, in the turning part and the second pass, v2f and low Re YS models perform better.

There is a proposed new environmentally friendly technology of airport’s sanitary sewage water treatment, which allows improving the quality of the treated sewage water, diminishing harmful impacts on environment during sewage sludge utilization, and obtaining additional amount of alternative energy sources. Within the bounds of this technology, there is a proposal to organize two additional processes. The first one is a process of microalgae cultivation, using mechanically and biologically treated sewage water as a growing medium. For cultivation, there is a proposed culture of microalgae with high lipid content. It allows improving the quality of treated water and producing liquid biofuel out of the cultivated algae. A new construction of photobioreactor is proposed there. This construction allows intensifying the cultivation process. The second one is the process of anaerobic digestion of sewage sludge along with biomass, which remains as waste product after biofuel production out of cultivated microalgae. The digestion is proposed to conduct in special installations, using new method to organize it. The method allows obtaining environmentally friendly organic fertilizer, biogas with increased methane content and carbon dioxide, which can be used for microalgae cultivation process.

Statistical regression models have a wide usage in various estimation problems. They can be used to find a relationship between dependent and independent variables. Generally, it is using regression parametric models to find the type of relationship between variables. But some problems could not be estimated with linear models, as they have a nonlinear effect on dependent variable. This study aims to show the difference between linear and nonlinear techniques. In this study, emission parameters of a military-type turboprop engine is determined at unmeasured operating points on the basis of data collected at various loads with the aid of regression techniques. It is using multivariate linear regression, additive models with B-spline basis function, and smoothing splines. Three different techniques used to reveal best approximation to the dataset. It is observed that the effect of three parameters: revolution per minute (min-1), air/fuel ratio (kg air/kg fuel), and mass flow rate (kg.s-1) to different mass flow rates (CO (kg/s), CO2 (kg/s); UHC (kg/s), NO2 (kg/s)). In the end of the study, results obtained from benefited approximations were compared with each other using MSE (mean squared error) performance criteria.

Airports are considered from the point of power consumption for the provision of technological processes. The study is aimed to define the potential for energy conservation at airports of Ukraine and for the improvement of environment quality at the adjoined area. The major reasons of energy losses at airports are defined. The best practices of energy-saving solutions in European countries are analyzed and recommended for application in Ukrainian airports on the example of the range of international airports of Ukraine. The environmental effects and economic efficiency of energy conservation projects and prospects of their implementation are considered.

Emissions threaten not only human health but also the human environment and air quality. The most well-known emissions sources are ships, air planes, motor vehicles, and various industrial facilities. Among these emissions sources, ships are the biggest emitters of air pollution. Increasing numbers of ships and new port investments near the coast exacerbate health risks. If measures are not taken, the threat will increase incrementally in the near future with the contribution of ship operations in new port investments, such as Asyaport. Asyaport is in the Tekirdag region, which serves as bridge connecting the continents of Asia and Europe. The Tekirdag region is also one of the most highly populated and industrialized areas in Turkey. Because of population density and industrialization, the amounts of emissions are very important for local residents of Tekirdag. In this study, the authors aim to reveal how the new port affects air quality and human health risk in the Tekirdag region. For this aim, two-step analyses were conducted. First, a theoretical perspective of the ship emissions was considered based on chemical reactions during combustion per fuel oil kilogram and different navigation phases, i.e., cruising, maneuvering, and hotelling. Second, various scenarios were considered in cases of different sulfur limitation policies and use of alternative fuel (liquified natural gas (LNG)) for the numerical investigation. Finally, these scenarios were implemented in Asyaport. The emissions (CO₂, SO₂, SO₃, NO, NO₂, total nitrogen oxides (NOx), and sulfur oxides (SOx)) were illustrated for different fuels and different percentages of sulfur until the year 2045, and the grand total of SOx and NOx emissions was estimated as 1,249,278 tons.

Using smart and functional materials in textile applications has gained much more importance over the last decade in order to provide and improve some specific end product properties. In the present work, we designed spacer weft-knitted fabrics for the purpose of protective clothing – which has an electromagnetic shielding effect and a good thermal property – of aircraft crew. To provide two functions in one fabric, spacer weft-knitted fabrics composed of inherently thermally perfect wool and electrically conductive silver-plated nylon yarns were developed initially. The application of temperature-responsive polymer (TRP) and phase change material (PCM) onto these fabrics was then performed in order to enhance their thermal properties. The structural characterizations and thermal analyses performed showed that the developed fabrics demonstrated not only much better electromagnetic shielding effect but also improved thermal performance than ordinary clothing as underwear.

Technological aspects and market-wise applications of electric-powered UAVs are emerging. UAVs proved to be a candidate to be an indispensable tool in our life. In this chapter, applications and future trends of UAVs are discussed. Electric propulsion of UAVs seems to be a key enabler for the most of the applications. It can be concluded that the more autonomous and lighter the UAV is, the more electric power is preferred.

The environmental issues associated with energy consumption and increasing energy demand are a major concern of this century. To reduce environmental impact and achieve more sustainable society, novel approaches are developed day by day. In the current chapter, a novel approach to evaluate environmental impact of a turbojet engine is presented. Recently defined, a genuine indicator, namely, greenization factor, is a measure to understand contribution of the system improvement to environmental impact reduction. The current study aims to derive this indicator defined for other energy conversion systems to assess propulsion systems from the same perspective. For this purpose, an application to a turbojet engine is also introduced for a better understanding of the methodology.

The objective of integrated navigation systems is to estimate the navigation states reliability, which includes position and velocity of the aircraft, from the inertial measurements and the external aids despite the possible occurrence of devices faults. In this study three different integrated systems have been studied without taking into consideration any faulty case: integrated baro-inertial (IBI), integrated inertial-GPS (IIG) and integrated baro-inertial-GPS (IBIG). IBI and IIG navigation systems have been designed using a complementary Kalman filter (CKF), which estimates the error model parameters. Simulation results show that fluctuations for IIG altimeter errors are the largest ones for the three altimeters. The second largest errors are acquired by IBI altimeter and finally, the best results are obtained by the fused IBIG altimeter.

A new statistical fault detection technique based on the Kalman filter innovation covariance testing is proposed. The generalized variance (determinant) of the random Wishart matrix is used for this purpose as a fault detection statistic, and the testing problem is reduced to the determination of the asymptotes for Wishart determinants. In the simulations, the flight dynamics model of the F-16 fighter is investigated, and detection of sensor and actuator/surface failures, which affect the innovation covariance, is examined.

During flight process of an aircraft, air traffic control officer (ATCO)-pilot interaction commonly faces frequency misunderstandings, since the quality of radio communication has different types of disturbance including background noise, atmospheric disturbances, and high-power RF sources. In this study, the most common misunderstandings of phraseology structure were analyzed to reduce the radio communication failure. Pilotage and air traffic control (ATC) students listened to a real Yesilkoy approach voice record between an ATCO and a pilot. Besides, a survey, defining their listening failures, was given to the participants. The result of the survey showed that the common radio communication failures between the ATCO and the pilot are related with the similarity of NATO (North Atlantic Treaty Organization) phonetic alphabet and numbers. To reduce these similarities, a phonetic alphabet usage rule is proposed in order to prevent the spelling conflicts in this study.