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As a fuel commonly used by air heaters for ground tests of high-speed aircraft, the combustion mechanism of ethanol in air heaters is still unclear, especially the atomic-level chemical mechanism of important intermediate products represented by hydrogen in maintaining stable flame combustion needs to be further studied. In this paper, the combustion process of ethanol/oxygen mixtures under different hydrogen additions was simulated using the reactive force field (ReaxFF) molecular dynamics (MD) method. The results show that increasing the proportion of hydrogen in the mixed gas can not only reduce the ignition delay time of ethanol combustion but also promote the consumption of ethanol and accelerate the progress of the combustion reaction. It was also found that hydrogen and ethanol produced a competitive relationship for oxygen, which changed the ideal stoichiometric ratio (1:3) of complete combustion of ethanol and oxygen and significantly affected the intermediate products and reaction paths of ethanol and oxygen. In addition, increasing the combustion reaction temperature will affect the reaction path of ethanol/oxygen, and the number of intermediate products produced will reach the peak faster and then decompose. Theoretical support for a deeper understanding of the intermediate product hydrogen in the combustion of the three-component air heater of ethanol/liquid oxygen/air and also for improving the combustion efficiency of liquid rocket engine fuel are provided in this study.

We have successfully synthesized ZnO nanoparticles (NPs) from solution combustion method using combustible fuel (Green gram). XRD pattern confirms that the prepared compound is composed of wurtzite hexagonal zinc-oxide. FTIR spectrum of ZnO NPs shows the band at ~ 417 cm^-1 associated with the characteristic vibration of Zn-O. The UV-Vis spectrum shows a strong absorption band at ~ 365 nm which is blue shifted due to quantum confinement effect. TEM images show the average sizes of the nanoparticles are found to be almost ~ 15–30 nm. The as-synthesized product shows good electrochemical sensing of dopamine. Furthermore the antibacterial properties of ZnO NPs were investigated by their bactericidal activity against four bacterial strains using the agar well diffusion method.

In the present work, Zinc Oxide nanoparticles (ZnO Nps) have been prepared by a simple and low temperature solution combustion method using Zinc nitrate as a precursor and solid water melon juice as a novel fuel for the first time. The structure and morphology of the synthesized ZnO NPs have been analyzed using various analytical techniques such as Powder X-ray diffraction, FTIR spectroscopy, Raman spectroscopy, UV-Visible spectroscopy, photoluminescence spectroscopy, scanning electron microscope and transmission electron microscope. ZnO NPs show good photo catalytic activity for the degradation of methylene blue (MB) dye. It also shows significant antibacterial activities against three bacterial strains.

In this paper, we have successfully synthesized ZnO nanoparticles (Nps) via solution combustion method using sugarcane juice as the novel fuel. The structure and morphology of the synthesized ZnO Nps have been analyzed using various analytical tools. The synthesized ZnO Nps exhibit excellent photocatalytic activity for the degradation of methylene blue dye, indicating that the ZnO Nps are potential photocatalytic semiconductor materials. The synthesized ZnO Nps also show good electrochemical sensing of dopamine. ZnO Nps exhibit significant bactericidal activity against Klebsiella aerogenes, Pseudomonas aeruginosa, Eschesichia coli and Staphylococcus aureus using agar well diffusion method. Furthermore, the ZnO Nps show good antioxidant activity by potentially scavenging 1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The above studies clearly demonstrate versatile applications of ZnO synthesized by simple eco-friendly route.

Y₂O₃:Eu nanopowders were synthesized by urea combustion method containing different concentration of Eu. The synthesized Y₂O₃:Eu nanopowders were characterized by X-ray diffractometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), energy dispersive X-ray analysis (EDX) and photoluminescence spectroscopy (PL). The particle size was calculated to be in the range of 15–30 nm using Scherrer's formula. The Ia-3 structure of synthesized Y₂O₃:Eu nanopowders were confirmed with X-ray diffractometry. The crystallinity of Y₂O₃:Eu nanopowders were confirmed by SAED and TEM images. The ⁵D₀–∑⁷F_J (J = 0, 1, 2, 3) and ⁵D₁–⁷F₁ transitions bands were observed at 575–650 and 530–550 ranges in the photoluminescence spectrum. The concentration quenching was estimated to be about 5 mol% of Eu. The best chromaticity to the standard red color was observed with the sample containing 3 mol% of Eu.

This paper presents a numerical method to calculate combustion coupled ejection flow in nozzle processes in Liquid Rocket Motor (LRM). A two-dimensional axi-symmetric numerical simulation for the injector element-combustor-and-nozzle model is carried out using the Finite Different (FD) method. In the simulation, the available Computational Fluid Dynamics (CFD) software FLUENT is employed with three key enhancements for material modelling. Firstly, the influence of the two-phase reacting flow is considered, in which the coupled implicit two-step finite difference method to solve the Re-averaged conjugated N-S equation with component conservative equation is used. Secondly, the 17-component, 12-step finite-rate chemical reaction model is employed. Thirdly, the Baldwin-Lomax model is used as turbulence model. These three enhancements are incorporated into the FLUENT code through its user subroutine capability. For both ignition and exhausted stages, the unsteady flow method is used while the steady flow method is adopted for the normally working stage. The distributions of the flow parameter in the combustor-nozzle system are achieved. In addition, the variations of flow parameter along with the time in different stages are also obtained. The results obtained from the numerical simulation are compared with independently available field tests data. Good agreement is observed.

Nitrous oxide, or N₂O, is a greenhouse gas that is largely considered to be the cause for depletion of the ozone layer. As nearly 70% of the global emissions seem to arise from bacterial and fungal denitrifications and nitrification processes in soils, there is a growing concern to identify mitigation techniques to improve the atmosphere in which we live. Fertilizers in agricultural soils are the primary source. This chapter will explain the causes of nitrous oxide emissions in the atmosphere as well as explore these mitigation methods that have been researched, tested and successfully implemented.

Some people think that carbon and sustainable development are not compatible. This textbook shows that carbon dioxide (CO₂) from the air and bio-carbon from biomass are our best allies in the energy transition, towards greater sustainability. We pose the problem of the decarbonation (or decarbonization) of our economy by looking at ways to reduce our dependence on fossil carbon (coal, petroleum, natural gas, bitumen, carbonaceous shales, lignite, peat). The urgent goal is to curb the exponential increase in the concentration of carbon dioxide in the atmosphere and hydrosphere (Figures 1.1 and 1.2) that is directly related to our consumption of fossil carbon for our energy and materials The goal of the Paris agreement (United Nations COP 21, Dec. 12, 2015) of limiting the temperature increase to 1.5 degrees (compared to the pre-industrial era, before 1800) is becoming increasingly unattainable (Intergovermental Panel on Climate Change (IPCC), report of Aug. 6, 2021). On Aug. 9, 2021 Boris Johnson, prime minister of the United Kingdom, declared that coal needs to be consigned to history to limit global warming. CO₂ has an important social cost…

Natural gas consists mainly of methane (CH₄) and ethane (CH₃CH₃) and other hydrocarbons in small quantities. Depending on the source it may also contain CO₂, nitrogen (N₂), hydrogen sulfide (H₂S) and helium (He). It is very abundant and its combustion contributes to the increase of the CO₂ content in the biosphere. Natural gas is a non-renewable fuel (Section 5.1). It is widely used to produce electricity, heat, chemicals including hydrogen, and hydrocarbons (liquid fuels) and as a fuel for motor vehicles…

A new kind of Opposite Axial Piston Engine (OAPE) in small scale specially designed for the portable generating system was presented. The working theory of OAPE was studied, based on which the combustion process was simulated in FLUENT. Then the internal flow field and the variation of temperature and pressure in cylinder were recorded. Results show the flame front is a sphere centered at the spark point. The maximal pressure in power cylinder is 2.13Mpa and maximal pressure in charge cylinder is 0.235Mpa. The work done by power cylinder per cycle is 1.24J, while the charge cylinder consumes 0.22J per cycle.

The characteristics of the flow, the combustion field and NOx emissions in the coal-fired boiler are numerically investigated under different burner layer combination modes for a 660 MW swirling opposed coal-fired utility boiler. The simulation results are relatively close to the actual measured results, with relative errors of less than 10%. The results demonstrate that at the rated load of 5 mills in service, the differences in NOx emissions and carbon contents in fly ash is small in cases of the same-layer burner operating in the front wall and in the rear wall. Stopping upper layer burners enhances air classification and increases the residual time of pulverized coal particles, as compared to stopping the middle layer burners; consequently, the NOx emission and carbon content in the fly ash are reduced by relative values of 9.5% and 9.8%, respectively. In addition, stopping upper layer burners reduces NOx emission and improves combustion efficiency in actual operational conditions.

Through the characteristic experiment, the chromatographic experiments and the thermal analysis experiments, this paper obtains that below 70°C the difference between the curve of CO and CO2 concentration of the organic sample was not significant. The production of CO and CO2 increased rapidly when the temperature rise up to more than 120°C and the maximum production rate of CO and CO2 occurs when the mineral content of organic is 5%. The oxygen consumption of different mineral content in organic samples decreases first and then increases with the increase of temperature. Among them, the maximum oxygen consumption occurs when the mineral content of organic is 5% with the increase of temperature, and the exothermic ox.

Through the investigation on flame-retardant properties of three kinds of inner-spring mattresses, it is found that without flame retardant, the heat release rate (HRR) of spring mattress is up to 600 kW, the concentration of carbon monoxide (CO) and carbon dioxide (CO₂) is 0.08% and 1.5% respectively. Thus, mattress has a very high fire risk. It could cause injuries and deaths through spreading of fire and emitted gases. The mattress with only fabric treated with flame retardant could be ignited, but did not cause the flame spread across a large area, the flame retardant performance satisfied grade B1 in GB 8624-2012. For the mattress which has both fabric and filler being flame retardant, the flame extinguished soon after the ignition sources were removed. Therefore, flame retardant performance for the last mattress was very well.

The combustion and NOx (Nitrogen Oxide) emission characteristics experiment fueled with conventional diesel fuel and four different fuel blends of acidic oil biodiesel (B5, B10, B15 and B20) were conducted in a four-cylinder, electronic controlled high-pressure common-rail, turbocharged diesel engine without any structure modifications. The results showed that operations with acidic oil biodiesel blends had increase in ignition delay, maximum in-cylinder pressure, heat release rate peak in diffusion combustion duration, cumulative heat release and maximum in-cylinder temperature compared with baseline diesel. In addition, the heat release rate peak and in-cylinder pressure rise rate peak in premixed combustion duration of biodiesel blends were decreased and their crank angular positions were lagged obviously. The NOx emission of biodiesel blends increased, especially at high loads.