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Diesel has traditionally been considered the best-suited and most widely used fuel in various sectors, including manufacturing industries, power production, automobiles and transportation. However, with the ongoing crisis of fossil fuel inadequacy, the search for alternative fuels and their application in these sectors has become increasingly important. One particularly interesting and beneficial alternative fuel is biodiesel derived from bio sources.

In this research, an attempt was made to use biodiesel in an unconventional micro gas turbine engine. It will remove the concentric use of diesel engines for power production by improving fuel efficiency as well as increasing the power production rate. Before the fuel is used enormously, it has to be checked in many ways such as performance, emission and combustion analysis experimentally.

In this paper, a detailed experimental study was made for the use of Spirulina microalgae biodiesel in a micro gas turbine. A small-scale setup with the primary micro gas turbine and secondary instruments such as a data acquisition system and AVL gas analyser. The reason for selecting the third-generation microalgae is due to its high lipid and biodiesel production rate. For the conduction of experimental tests, certain conditions were followed in addition that the engine rotating rpm was varied from 4,000, 5,000 and 6,000 rpm. The favourable and predicted results were obtained with the use of microalgae biodiesel.

The performance and combustion results were not exactly equal or greater for biodiesel blends but close to the values of pure diesel; however, the reduction in the emission of CO was at the appreciable level for the used spirulina microalgae biodiesel. The emission of nitrogen oxides and carbon dioxide was a little higher than the use of pure diesel. This experimental analysis results proved that the use of spirulina microalgae biodiesel is both economical and effective replacement for fossil fuel.

The depletion of fossil fuel and emissions of harmful gases forced the pioneers in search of alternate energy source. The purpose of this study is to present an effective use of hydrogen fuel for turbojet engines based on its exergetic performance.

This study was performed to measure the assessment of exergetic data of turbojet engines. Initially, the test was carried out on the Jet A-1 fuel. Then, a series of similar tests were carried out on turbojet engines with hydrogen fuel to measure their performance results. Finally, the exergetic values of both were compared with each other.

The introduction of hydrogen fuel reduced the exergy efficiency, and a 10 per cent reduction was observed in exergy efficiency. Simultaneously, the waste exergy rate increased by 9 per cent. However, because of the high specific fuel exergy, hydrogen fuel was better than Jet A-1 fuel. Note that parameters such as environmental effect factor and ecological effect witnessed an increase in their index owing to the addition of hydrogen.

Introduction of alternative blends is necessary for achieving lower emission of gases such as CO, NOx and CO₂ from gas turbine engines without compromising on performance. The Jet A fuels were replaced by blends to obtain better emission characteristics.

The use of hydrogen in turbojet engines showed an adverse effect on exergetic performance. However, it was very impressive to see a 200 per cent reduction in emissions. From the comparison of exergy efficiency results of inlet, combustion and nozzle, it is evident that the combustion chamber has the largest values of exergy ratio, waste exergy ratio, cost flow, ecological factor, environmental factor and fuel ratio owing to irreversibility in the combustion process.

The purpose of this paper is to estimate different air–fuel ratio motor shaft speed and fuel flow rates under the performance parameters depending on the indices of combustion efficiency and exhaust emission of the engine, a turboprop multilayer feed forward artificial neural network model. For this purpose, emissions data obtained experimentally from a T56-A-15 turboprop engine under various loads were used.

The designed multilayer feed forward neural network models consist of two hidden layers. 75% of the experimental data used was allocated as training, 25% as test data and cross-referenced by the k-fold four value. Fuel flow, rotate per minute and air–fuel ratio data were used for the training of emission index input values on the designed models and EI_CO, EI_CO2, EI_NO2 and EI_UHC data were used on the output. In the system trained for combustion efficiency, EI_CO and EI_UHC data were used at the input and fuel combustion efficiency data at the output.

Mean square error, normalized mean square error, absolute mean error functions were used to evaluate the error obtained from the system as a result of the test. As a result of modeling the system, absolute mean error values were 0.1473 for CO, 0.0442 for CO₂, 0.0369 for UHC, 0.0028 for NO₂, success for all exhaust emission data was 0.0266 and 7.6165e-10 for combustion efficiency, respectively.

This study has been added to the literature T56-A-15 turboprop engine for the current machine learning methods to multilayer feed forward neural network methods, exhaust emission and combustion efficiency index value calculation.

Chemical reaction effects are added to the governing equation. This paper aims to get the solution by converting the partial differential equation into an ordinary differential equation and solve using a perturbation scheme and applying the boundary conditions.

In this paper, the authors discussed the chemical reaction effects of heat and mass transfer on megnato hydro dynamics free convective rotating flow of a visco-elastic incompressible electrically conducting fluid past a vertical porous plate through a porous medium with suction and heat source. The authors analyze the effect of time dependent fluctuating suction on a visco-elastic fluid flow.

Using variable parameters of the fluid, the velocity, temperature and concentration of the fluid are analyzed through graphs.

The velocity profile reduces by increasing the values of thermal Grashof number (G_r), mass Grashof number (G_c) and the magnetic parameter (M). On the other hand, the velocity profile gets increased by increasing the permeability parameter (K). The temperature profile decreases by raising the value of Prandtl number (P_r) and frequency of oscillation parameter (ω). However, the source parameter (S) has the opposite effect on the temperature profile. The concentration profile reduces in all points by raising the chemical reaction parameter K_l, Schmidt number S_c, frequency of oscillation ω and the time t.

The purpose of this study is to predict the performance and emission characteristics of micro gas turbine engines powered by alternate fuels. The micro gas turbine engine performance, combustion and emission characteristics are analyzed for the jet fuel with different additives.

The experimental investigation was carried out with Jet A-1 fuel on the gas turbine engines at different load conditions. The primary blends of the Jet A-1 fuels are from canola and solid waste pyrolysis oil. Then the ultrasonication of highly concentrated multiwall carbon nanotubes is carried with the primary blends of canola (Jet-A fuel 70%, canola 20% and 10% ethanol) and P20E (Jet-A 70% fuel, 20% PO and 10% ethanol).

The consumption of the fuel is appreciable with the blends at a very high static thrust. The 39% reduction in thrust specific fuel consumption associated with a 32% enhance in static thrust with P20E blend among different fuel blends. Moreover, due to the increase in ethanol concentration in the blends PO20E and C20E lead to a 22% rise in thermal efficiency and a 9% increase in higher oxygen content is observed.

The gas turbine engine emits very low emission of gases such as CO, CO₂ and NOx by using the fuel blends, which typically reduces the fossil fuel usage limits with reduced pollutants.

The emission of the gas turbine engines is further optimized with the addition of hydrogen in Jet-A fuel. That is leading to high specific fuel exergy and owing to the lower carbon content in the hydrogen fuel when compared with that of the fossil fuels used in gas turbine engines. Therefore, the usage of hydrogen with nanofluids was so promising based on the results obtained for replacing fossil fuels.

This study seeks the effect on static thrust, thrust specific energy consumption (TSEC) and exhaust emissions of euro diesel-hydrogen dual-fuel combustion in a small turbojet engine.

Experimental studies are performed in a JetCat P80-SE type small turbojet engine. Euro diesel and hydrogen is fed through two different inlets in a common rail distributing fuel to the nozzles. Euro diesel fuel is fed by a liquid fuel pump to the engine, while hydrogen is fed by a fuel-line with a pressure of 5 bars from a gas cylinder with a pressure of approximately 200 bars.

At different engine speeds, it is found that there is a decrease at the TSEC between a range of 1% and 4.8% by different hydrogen energy fractions (HEF).

The amount of hydrogen is adjusted corresponding to a range of 0–20% of the total heat energy of the euro diesel and hydrogen fuels. The small turbojet engine is operated between a range of 35,000 and 95,000 rpm engine speeds.

On the other hand, remarkable improvements in exhaust emissions (i.e. CO, CO₂, HC and NO_x) are observed with HEFs.

This is through providing improvements in performance and exhaust emissions using hydrogen as an alternative to conventional jet fuel in gas turbine engines.

This paper presents preliminary results of the modeling of a large autonomous quad-rotor airship, with flying wing shape. This airship is supposed to be a flexible body. This study promotes an entirely analytical methodology with some assumptions. In this study and as first assumption, the shape of the careen is supposed to be an elliptic cone. To retrieve the velocity potential shapes, this paper solved the Laplace’s equation by using the sphero-conal coordinates. This leads to the Lamé’s equations. The whole system equations governing the interaction of air–structure, including the boundary conditions, is solved in an analytical setting.

This paper opted for a modeling and determination of the added masses of a flexible airship by an analytical method illustrated by a comparison with a geometric method. This analytical method includes the study of complex functions which are the Lamé functions.

This paper provides an analytical way to estimate an aerodynamic phenomenon which acts on the airship and in particular on its envelope and known as the phenomenon of added masses or virtual masses, as well as the means of defining it and the calculation analytically for the case of the flexible airship.

Considering that the calculation of the added masses is very difficult and the numerical methods increase the number of degrees of freedom, the analytical method established in this paper has become a solution of calculations of these virtual masses.

This paper includes an application for determining the added masses of a new generation MC500 airship.

This paper allows defining an analytical method which determines the added masses of an airship, which helps the automation engineer to develop a control strategy to stabilize this airship.

The rise in demand and high utilization of fuel causes severe environmental threat for the nations on the globe. Rapid burning potential of hydrogen produces enormous amount of thrust, and it is mainly owing to wide flame range and less onset of ignition.

The significant contribution of hydrogen as fuel has been explored by several researchers around the globe recently to use in aviation sector owing to its eco-friendly nature. Hydrogen is a safe and clean fuel, and it can be generated from several sources. The effects of addition on hydrogen on gas turbine on combustion characteristics and emission concentration level on atmosphere have been reviewed in this paper.

Incorporation of hydrogen is effective reducing nitrous oxide emission, high calorific value and flame less combustion. Addition of hydrogen to higher proportions enhances the combustion performance, minimizing the setbacks of conventional fuel and meets the specified standards on emission.

From the literature review, the comparative study on hydrogen with other fuel is explained. This paper concludes that addition of hydrogen in fuel enhances the performance of combustion on gas turbine engine along with significant reduction in emission levels.

This paper aims to investigate the effect of additives in Jet-A fuel blends, especially on performance, combustion and emission characteristics.

Jet-A fuel was formed by using Kay’s and Gruenberg–Nissan mixing rules by adding additive glycerol with TiO₂. While measuring the combustion performance, the amount of oxygen content present in fuel and atomization are the key factors to consider. As such, the Jet-A fuel was created by adding additives at different proportion. A small gas turbine engine was used for conducting tests. All tests were carried out at different load conditions for all the fuel blends such as neat Jet-A fuel, G10T (glycerol 10% with 50 ppm TiO₂ and Jet-A 90%), G20T (glycerol 10% with 50 ppm TiO₂ and Jet-A 90%) and G30T (glycerol 10% with 50 ppm TiO₂ and Jet-A 90%).

From tests, the G20T and G10T produced better results than other blends. The thermal efficiency of the blends of G20T and G10T are 22% and 14% higher than neat Jet-A fuel. Further, the improved static thrust with less fuel consumption was noticed in G20T fuel blend.

The G20T blends showed better performance because of the increased oxygenated compounds in the fuel blends. Moreover, the emission rate of environmentally harmful gases such as NOx, CO and HC was lower than the neat Jet-A fuel. From the results, it is clear that the rate of exergy destruction is more in the combustion chamber than the other components of fuel.

The purpose of this paper is to find the pressure and the knocking phenomena. To get the pressure values, the butterworth bandpass filter was used and the potential of knocking was found by using peak-to-peak pressure values and also the species concentration. Cooled exhaust gas recirculation was the method used to minimize the knocking occurrence in the engine. Moreover, the effect of premixed methanol and start of engine (SOI) on knocking were also determined.

This paper deals with the compression ignition engine to investigate the unfavorable knocking behavior. The tests were carried out with the 3D model of engine fueled with waste cooking oil blended with TiO2. A number of tests were taken to find the pressure variation and the species concentration at eight different locations in the computational model.

In doing the tests, the positive intended outcome was achieved. From results, it is clear that the SOI and premixed methanol mitigated the knocking process.

The species concentration and pressure in the form of filtered signal were proved to be the ideal methods for evaluating the knocking event in the engine.