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The present study investigates the significance of the utilization of biodiesel derived from waste cooking oil in diesel engines and its impact on engine output and environmental pollution after blending with diesel and 1-pentanol. The higher values of the ignition index and comprehensive performance index of 4.34 × 10−4mass/min°C2 and 13.71× 10−6 mass2/min2 °C3, respectively, for D70B20P10 (70 % diesel, 20 % biodiesel & 10 % 1-pentanol by volume) indicate superior combustion performance. At full load, carbon monoxide and unburned hydrocarbon emissions from 1-pentanol blended fuels decrease significantly, ranging from 40 % to 52 % and 30.76–46.15 % compared to diesel. The D70B20P10 also showed an improved thermal efficiency of 28.68 % among all tested fuels at full load but slightly lower than diesel (29.56 %). Diesel demonstrated superior in-cylinder pressure (ICP) of 77 bar and heat release rate (HRR) of 41.1 J/ºCA owing to its excellent combustion characteristics. Introducing 5–10 % 1-pentanol in blend improved combustion, elevating ICP and HRR, attributed to enhanced fuel atomization and oxygen content. The sustainable process index value obtained for a global index per person is 0.002×10−4cap Litre-1, which lies between 0 and 1, indicates sustainability and compatibility of biodiesel production demonstration by universal biofuels (Andhra Pradesh).

With growing desire to destroy per- and poly-fluoroalkyl substances (PFAS) now known to be detrimental to human health, a sound understanding of fluorocarbon combustion chemistry is important to efficient thermal destruction within incinerators. While most fluorocarbon combustion models and the sets of reactions contained within them were originally developed for the high temperatures encountered in flame suppression applications, they have often been used to assess PFAS destruction in incinerators, which emphasize a lower range of temperatures. We present results that demonstrate that low-temperature fluorocarbon oxidation pathways—not yet known to play a role in fluorocarbon combustion—impact key incinerator performance metrics, including: PFAS surrogate mole fractions, products of incomplete destruction, and waste destruction efficiencies. The results further point to the utility of NO as a potential additive. The present results show the influence of these pathways for CF3O2, for which some data are available, but analogous pathways would also occur for other fluoroalkylperoxy radicals, for which little is known. The results demonstrate the need for future work to identify and characterize low-temperature pathways more generally, consider such pathways in kinetic model development, and experimentally probe intermediate temperature conditions to better understand, design, and control thermal destruction technologies for improved PFAS management.

ORCh is a set of C++ routines to analyze the response of detailed chemical kinetics and determine the most influential species and elementary reactions for given operating conditions. The objective is to reduce the number of degrees of freedom to be solved in fluid mechanics simulations while still capturing most of the reactive flow physics. From a detailed chemical kinetics, ORCh returns a set of reduced chemical schemes of decreasing complexity. ORCh operates either from canonical laminar diffusion–reaction problems, such as one-dimensional premixed and diffusion flames, or turbulent/chemistry interaction models through the evolution of stochastic particles. The initial conditions of these canonical problems are representative of the inlets of the reactive flow system under study. In case of a significant reduction of the number of degrees of freedom, the control parameters of the reduced chemistry can be further optimized from a genetic algorithm to still match the reference detailed chemistry response. An illustrative application to tetrafluoromethane oxidation chemistry is discussed.

The main objective of the present study was to investigate combustion instability in a multi-cylinder radial piston engine with electronic fuel injection to ensure safety and reliability, maintain fuel efficiency, reduce harmful emissions, which has a positive impact on the environment. Multi-fractal analysis showed that IMEP (mean effective pressure) fluctuations are an anti-persistent process, meaning that there is no correlation between successive events. The return plots showed significant cyclic variability and instability in neighboring cylinders. The wavelet method and multiscale entropy analysis confirmed the results of the multifractal analysis, showing changes in the characteristics of the combustion process after the introduction of perturbations. The research-based on the first return map has shown an impact on the non-uniform and complex nature of the operation of the neighboring cylinders. The statistical analysis has shown that more than 60 % is slightly negatively skewness in most of the cases, and about 67 % of the cases indicate a leptokurtic distribution of IMEP. Finally, it is concluded that, the combustion of failure of one cylinder in a nine-cylinder engine affects the operation of the other cylinders, as demonstrated through advanced multifractal analysis techniques, return plots, return maps and multiscale entropy analysis.

Biomass, as a renewable energy source, has gained attention as a sustainable alternative to conventional fuels due to its global availability and usability in rural areas. However, biomass combustion presents challenges such as flame instability and pollutant emissions. This study compares the use of methane gas, wood shavings, and a combination of these two fuels, examining the effects of preheating and flame stability in the combustion of natural gas, biomass, and their co-firing using numerical methods. An equivalence ratio of 1 has been used to avoid a rich-fuel mixture, and an air mass flow rate of 0.0001 kg/s are considered to ensures a sufficient supply of oxygen for the combustion process. Biomass fuel particles are injected from the surface of the fuel and its particle diameter ranging between 5 and 10 μm. The results showed that using the combined fuel not only increased the flame temperature at the beginning of the combustion chamber but also achieved more complete and stable combustion, with over 97 % of the fuel consumed at the start of combustion. As a result of this complete combustion, the emissions of toxic gases CO and NOx in the combustion products reached zero. Additionally, preheating the air increased the flame temperature by 14 %, while preheating the fuel reduced NOx emissions by 24 %.

The combination of renewable energy and multifuel combined supply is an efficient way to deal with the energetic crisis and the pollution of environment. Ethanol, gasoline and oxyhydrogen participate in combustion by means of three independent supply paths, which can improve engine power and reduce gasoline consumption and gaseous pollutant emission at the same time. However, the optimization of ternary-fuel combined supply mode is a problem that must be clarified. In this study, the engine performance at four direct injection pressure (DIP), six direct injection timing (DIT), five intake manifold absolute pressures (MAP) and four speeds is studied under the condition of equal ethanol injection ratio and gasoline injection ratio. The experimental results show that ethanol direct injection forms a mixture with a better stratified combustion state than gasoline direct injection. Moreover, oxyhydrogen negatory pressure inhalation (ONPI) can effectually increase Pmax and IMEP, reduce APmax, CA 10–90, CA 0–10, CO emission, HC emission and particulate emission, but increase NOx emission. However, ethanol direct injection (EDI) can reduce NOx emission produced by ONPI, and oxyhydrogen can attenuate the negatory effect on mixture combustion due to the excessive latent heat of vaporization of ethanol. NO emission in EDI mode is reduced by an average of 28.39 % compared to gasoline direct injection (GDI) mode under different MAPs. In conclusion, the combustion and emission characteristics of the engine in EDI + gasoline port injection (GPI) + ONPI mode are better than those in ethanol port injection (EPI) + GDI + ONPI mode. And the control strategy of ''9–11 MPa DIP+250–300°CA BTDC DIT +16 L/min oxyhydrogen negative pressure inhalation volume (ONPIv)'' can improve the performance of EDI + GPI + ONPI engine while reducing emission.

The incomplete combustion of fossil fuels results in the emission of soot, a carbonaceous, solid fine powder that causes harm to human health and the environment. This study compares multiple linear regression (MLR) with three different machine learning (ML) models for predicting the threshold sooting index (TSI), a commonly employed index for measuring the sooting propensity of fuels. The dataset used for model development consists of experimental TSI data for 342 fuels, including various chemical classes, including oxygenated components like ethers and alcohols. Ten input features were employed, comprising eight functionalities, molecular weight, and the branching index (BI). These parameters used as input features have been demonstrated to affect fuels' physical and thermochemical properties. The ML models employed in this study are support vector regression with Nu parameter (NuSVR), extra trees regression (ETR), and extreme gradient boosting regression (XGBR). The models were trained, validated, and tested using randomly split datasets, with 56 % for training, 14 % for validation, and 30 % for testing. The accuracy of the MLR, NuSVR, ETR, and XGBR models for the entire dataset was 91 %, 96 %, 98 %, and 96 %, respectively. The mean absolute errors (MAE) of prediction were 3.4, 0.022, 0.011, and 0.028 for MLR, NuSVR, ETR, and XGBR respectively. These results highlight the effectiveness of the ML models in making predictions, with error levels similar to the uncertainties observed in experimental measurements. The developed ML models have been validated to ensure generalizability and can be used to predict petroleum fuels' TSI.

Hydrogen's ability to enhance carbon neutrality in combustion processes puts forward the use of hydrogenated fuels, both in the form of fuel and an energy carrier as a potential decarbonization solution. However, because of the nature of hydrogen, blending it with hydrocarbons causes crucial structural changes in the flame structure, including higher flame propagation velocities and higher flame temperatures, decreased instantaneous flame thickness, and increased risks of flame flashback and an increasing potential of NOx emissions due to higher flame temperatures. These attributes encourage a thorough examination of hydrogenated blends of hydrocarbon fuels. Using lean premixed fuels is another technique to achieve efficient and cleaner combustion. However, due to the problem of flame instability in lean premixed combustion, forecasting the design points in terms of flame attributes is critical for better combustor designs.In this study, conical (Bunsen type) lean premixed turbulent flames of hydrogenated natural gas-air mixtures are experimentally studied. Through chemiluminescence measurements of the OH* and CH* radicals and laser-induced Mie scattering, lean natural gas-air premixed flames are examined with subsequently increasing hydrogen addition rates up to 20% by volume and keeping the premixture velocity constant. The obtained data is utilized for exploring the dynamics of the turbulent flame front. The main turbulent premixed flame parameters we identified relate to the instantaneous and average topology of the flame such as the turbulent flame brush thickness and flame height. We also inferred global combustion parameters like the turbulent flame propagation speed from the experimental findings.

Combining stratified lean-burn techniques with methanol offers a promising path to achieving high efficiency and low emissions in direct-injection spark-ignition (DISI) engines. This work compares the stratified and homogeneous-stratified lean-burn characteristics of methanol/gasoline fuels on a DISI engine. Combustion and emissions characteristics under two stratified lean-burn strategies were investigated. The results indicate that compared to double-injection stratified lean-burn (DISL), single-injection stratified lean-burn (SISL) leads to more timely combustion, which deteriorates more slowly as the excess air ratio increases. Using M20 fuel with SISL achieves a higher tolerance for air dilution. At the same excess air ratio, SISL results in higher maximum in-cylinder pressure and combustion temperature, but lower exhaust temperature. The economic zone for SISL occurs with M40 fuel at λ = 1.3–1.6, whereas DISL's economic zone is within λ = 1.1–1.3. When λ is below 1.5, SISL produces higher hydrocarbon (HC) emissions but lower nitrogen oxides (NOx) emissions. However, as λ exceeds 1.5, HC emissions from DISL increase sharply while NOx emissions decrease significantly. The particle concentration from SISL is at least an order of magnitude higher than that from DISL, with particle size distribution forming a unimodal curve centered around accumulation mode particles. Conversely, DISL exhibits a quasi-bimodal distribution.

Calcium aluminate phosphor nanomaterials co-doped with europium and dysprosium (CaAl2O4: Eu2+, Dy3+) were prepared using a facile solution combustion technique. The structural and optical properties were investigated. The X-ray diffraction (XRD) results confirmed the presence of the monoclinic phase in all the samples, with few impurity phases in the samples synthesized at 300 °C and 400 °C. The Fourier-transform infrared analysis gave the expected chemical combustion results of the final product with few traces of Ca3Al2O6 impurities at low and very high synthesis temperatures. The XRD patterns displayed diffraction angles of the major peaks shifting to higher 2 theta as the synthesis temperature increased. This is attributed to an increase in particle sizes, which led to an increase in lattice parameters. The intensity of the prominent peak increased up to 500 °C due to improved crystal quality. The crystallite sizes of the as-prepared samples were determined using the Debye-Scherrer equation. It was noted that there is variation in the crystallite sizes with synthesis temperature. The UV–Vis graph shows that absorption edges also shifted to lower wavelengths with an increase in synthesis temperature. It was noted that the band gap increased with an increase in synthesis temperature up to 500 °C, but at temperature of 1000 °C, the band gap was observed todecrease. Scanning electron microscope micrographs showed that the samples had irregular shapes with pores and cracks. The study provides a simple route to synthesize CaAl2O4: Eu2+, Dy3+phosphors with optimum synthesis temperature, producing the most crystalline sample for use in lighting devices.

In this study, the low idle operation is defined as the engine running at the lowest engine speed with a few slight loads. Idling is necessary for most vehicles, especially for buses and trucks that frequently travel long distances, as drivers often rest inside the vehicle. However, under idling conditions, weak air flow and low air-fuel ratio result in poor air to fuel mixture, ultimately causing incomplete combustion and the production of more harmful exhaust emissions. Bioethanol, as a low-carbon fuel, has great potential for application in diesel engines due to its unique properties. In this research, the influences of different diesel-bioethanol blends (BE0, BE5, BE10, BE15) on combustion and emissions of a diesel engine were investigated under idle conditions. The main results show that there was no phase separation phenomenon even up to 15% bioethanol was directly blended with diesel by volume. And adding bioethanol to diesel had no significant impact on combustion pressure peak, but it postponed the start of combustion (SOC). Surprisingly, the nitrogen oxide (NOx) and smoke were simultaneously decreased by over 52% and 78% with the intervention of bioethanol, respectively.

Laminar flame codes have an important role in combustion modeling. They can provide a fundamental understanding of flame dynamics and provide a basis for building subgrid scale models in turbulent flow simulations. This paper presents Ignis, an open-source laminar flame code with the capability to offload submodels, like soot formation and radiation, using external packages and libraries. Ignis is written in C++, is documented with Doxygen, and is available on GitHub. It contains three different flame formulations: diffusion flames, premixed flames, and laminar flamelets solved in the mixture fraction coordinate. An option to facilitate creation of a diffusion flame table is also included. These options allow for Ignis to be used as a flame model for comparisons against experimental data, for use in turbulent subgrid models, or for flame structure investigations.

Used tyres pyrolysis is an efficient solid waste management strategy for used tyres and a growing method of fuel oil production. However, the impact of air emissions associated at different temperature on ambient air quality has not been determined. To solve this problem, a pyrolysis fixed bed reactor and a condensing unit for separating liquid from produced gas were designed and constructed. 0.20 kg of used tyres were pyrolysed in the reactor and air emissions from the reactor chamber was characterized for air pollutants using the E-instrument E8500. Using a combination of measured mass of pollutants, mass of tyre pyrolzed and time taken during pyrolysis, Emission Factors of the air pollutants were established from the study at 200 °C, 300 °C and 400 °C. The concentration measured between 200 °C - 400 °C were in the range of 15 -7497 mg/m3, 0 – 4680 mg/m3, 38.25 – 103, 277.76 mg/m3 and 2 – 293 mg/m3 for CO, NOx, HC and H2S respectively. The developed emission factors were in the range of 16.52 – 8370.04 g kg-1, 0 – 4470.26 g kg-1, 42.126 – 104,055.9 g kg-1 and 2.20 – 322.69 g kg-1. The designed and constructed pyrolysis reactor and condenser unit were effective for used tyre pyrolysis while the measured air pollutants concentration were higher for all pollutants except H2S using the Federal Ministry of Environment (FEPA, 1991) standard. Hence, it is necessary to carry out further studies on air pollution control from waste tyre pyrolysis at lower temperature.

The regulation of propellant combustion using ultrasonic waves is proposed. Under ultrasonic frequencies of 25–40 kHz, we systematically examined the combustion characteristics of Al particles, ammonium perchlorate (AP)/hydroxyl-terminated polybutadiene (HTPB) propellants, and Al-containing Al/AP/HTPB propellants. Ultrasonic treatment increased the ignition delay time of the Al particles by 48.3 %. However, it increased the burning rate of the AP/HTPB propellants by up to 26.1 % and decreased their ignition delay by 39.3 %. As the ultrasonic frequency increased, the burning rate of the solid Al/AP/HTPB propellants increased by 22.5 %, and the degree of Al agglomeration decreased, resulting in a 24 % decrease in the size of the condensed-phase combustion products. The action mechanism was analyzed in terms of the effects of ultrasonic waves on Al droplets and combustion flames. The introduction of ultrasonic waves split the Al droplets near the burning surface into smaller particles, which affected combustion efficiency. Bringing the diffusion flame closer to the burning surface affected the burning rate. These findings demonstrate that the combustion and agglomeration characteristics of solid propellants can be modified using ultrasonic techniques, providing a new method for controlling the thrust of solid rocket motors.

In many developing nations, wood is still commonly used as a fuel for domestic cooking. However, fuelwood combustion can have a pronounced effect on air quality by releasing considerable level of PAHs, thereby posing serious risk to global and environmental health. In this study, seven fuelwood samples were cut into small pieces (100 g) and subjected to open burning with a view to estimate PAHs emissions and their toxicity potentials. During combustion, sixteen basic PAHs were characterized by collecting gaseous emissions from the combustion on PUFs (Polyurethane foams) using probe from the air sampler. The PUFs were washed in a Soxhlet extractor with Acetone to extract the emission which was then analyzed using Gas Chromatography/Mass Spectrometry for characterization. Chrysene and Dibenzo[a, h]anthracene have the highest and lowest PAHs concentrations, respectively. All PAHs levels observed exceeded permissible limits of 1x10−6 and 1.2x 10−7 mg/m3 of European Union and World Health Organization, respectively. PAHs from cashew wood showed highest levels of toxicity and mutagenicity, while all the samples have the same carcinogenic effect, indicating that all the samples have the same environmental/harmful impacts, going by ∑PAHcarc/∑PAH ratios (ratio that indicates general harmfulness). The study concluded that despite the relatively low toxic, mutagenic and carcinogenic effects observed in this study, exposure to these concentrations for a long period should be avoided, especially for persons with existing known health conditions such as asthma, lung cancer and cardiovascular diseases.

Fossil fuels cause global warming and create greenhouse gases that cause irreparable environmental damage. On the other hand, because the combustion reactions are not completely done, dangerous compounds, such as nitrogen or carbon monoxide are produced which are very toxic and dangerous. As a result, innovative methods were implemented in combustion processes. One such method is to use a catalyst during the combustion process. This study used a molecular dynamics method to examine how the concentration of CuOCeO2 catalyst affected air-methane combustion in a helical microchannel. The results show that the maximum (Max) values of density (Dens), velocity (Velo), and temperature (Temp) in the excess oxygen (EO) state were 0.142 atoms per second, 0.35 Å/ps, and 1089 K, respectively, when the atomic ratio of CuOCeO2 increased from 1 % to 4 %. Subsequently, these values exhibited a declining trend. Also, the values of heat flux (HF), thermal conductivity, and combustion efficiency in 4 % catalyst reached the max values of 2038 W/m2, 1.15 W/m·K and 88 %. The results related to the max values of Dens, Velo, and Temp for the oxygen deficiency state had a similar trend and increased to the max values of 0.103 atom/Å3, 0.41 Å/ps, and 1024 K in 4 % catalyst, and then decreased by increasing the catalyst ratio of CuOCeO2 and reaching 10 %. The thermal behavior of nanostructure was more optimal in the deficient oxygen medium.

The primary focus of this study is the validation of composite additives with the help of additional optimization methods and the analysis of its effect on the combustion characteristics of compression ignition (CI) engines. Previous work on the identification of the correct multi additive combination by Taguchi and the TOPSIS optimization method has shown substantial improvements in the performance and emission characteristics of CI engines. The same work was extended using the GRA Optimization method with the Multi-Criteria Decision-Making (MCDM) optimization technique known as the Analytic Hierarchy Process (AHP) to validate the optimization results from the previous optimization work. Remarkably, all optimization methods yielded consistent results, pointing to the superiority of the composite additive sample ‘D8EH6E4 hence supporting the outcome of previous work. Subsequent testing and comparison of this novel composite additive with baseline diesel fuel for combustion characteristics analysis demonstrated notable improvements in combustion parameters, including a 25 % reduction in the rate of pressure rise, an 18 % decrease in net heat release rate, and a 6 % decrease in mean gas temperature.

Poor clearances, misalignments, and carbon deposits in a turbocharger due to high running hours can decrease engine efficiency. This study analyzes the effects of turbocharger reconditioning on the performance and emissions formation of a marine diesel generator engine. The engine test experiments were performed on a university training ship's auxiliary diesel engine with 4309 running hours before and after the TC overhaul. As a result, cylinder peak pressure was increased by a maximum of 3.57 % while fuel saving of 5–8 g/kWh was realized. Lower exhaust gas temperatures and improved charge air pressure by up to 7.7 % were recorded. A significant CO emission reduction of 21.6 % was recorded at idle load whereas NOx and CO2 emissions were reduced to a maximum of 4.86 % and 7.30 % at 50 % engine load. The results indicate that scheduled TC overhaul and maintenance are very useful to improve the engine’s fuel economy, and performance and reduce exhaust emissions.

Using auto-combustion approach, cobalt ferrite nanoparticles doped with Zn+2 with the basic chemical composition ZnxCo1-xFe2O4 (x = 0 to 1: in steps of 0.25) were prepared. Phase confirmation of the proposed samples was confirmed through XRD studies. XRD pattern of the calcined ferrites revealed single phase spinel cubic structure. At room temperature, using HIOKI LCR meter (Model no: 3520-50) the dielectric measurements in the frequency range 102 Hz–106 Hz were performed. Dielectric constant (ε′) and dielectric loss tangent (tan δ) of synthesized nano-materials were investigated as a function of frequency and Zn+2 concentration at ambient temperature and all the samples exhibited dielectric dispersion. Magnetic measurements for ZnxCo1-xFe2O4 nano-ferrites were carried out at room temperature using a vibrating sample magnetometer (VSM), and all the samples of the system CoZnFe2O4 exhibited ferromagnetic behavior.

Fossil diesel is a significant global fuel; however, environmental concerns and resource scarcity necessitate alternative fuels. Third-generation microalgae biodiesel (MB), despite its carbon neutrality, leads to higher oxides of nitrogen (NOx) emissions and poor engine performance. Renewable diesel (RD), also known as hydrotreated vegetable oil (HVO), could reduce these issues. A quasi-dimensional multi-zone combustion model is employed in this study to look into how different fuel blends of diesel, C. cohnii MB, and algae-derived RD affect the performance, combustion, and emissions of a compression ignition (CI) engine. The study uses a 2000 rpm engine arrangement with different engine loads, and validates the computational analysis with an experimental test engine arrangement. The study aims to explore the potential of sustainable biofuels in CI engines. D70MB30 (70 vol% diesel, and 30 vol% MB) fuel blend leads to a higher ignition delay period (IDP) while lowering peak cylinder pressure (PCP) and peak heat release rate (PHRR) compared to D100; however, when RD is added to diesel-MB fuel blends, it reduces IDP and increases PCP and PHRR. Brake specific fuel consumption (BSFC) for the D70MB30 blend rises by 5.28–8.9 %, while brake thermal efficiency (BTE) reduces by 0.98–4.27 %. However, RD in MB blends reduces BSFC by 1.57–3.41 % and marginally enhances BTE, resulting in greater fuel economy and efficiency. D70MB30 fuel blend results in higher specific carbon dioxide (CO2) emissions and oxides of nitrogen (NOx) emissions while lowering particulate matter (PM) and smoke emissions compared to neat diesel due to its high intrinsic oxygen content. In contrast, RD with the MB blend reduces specific CO2 and NOx emissions; however, it increases PM and smoke emissions due to the NOx-PM trade-off. The optimum results occur with a full load and D70MB15RD15 (70 vol% diesel, 15 vol% MB, and 15 vol% RD) fuel blend. Compared to the D70MB30 blend, D70MB15RD15 reduces BSFC, specific CO2, and NOx by 2.15 %, ∼1%, and 8.37 %, respectively, while increasing PM emissions at 100 % load.

A novel semi-organic combustion approach using orange and lemon juice as chelating agents is employed to synthesize the perovskite Sr0.8X0.2Co0.2Fe0.8O3-δ (x = La, Ce) cathode for IT-SOFCs. This approach has been found to exhibit lower toxicity compared to chemical routes and lower impurities compared to green routes. The structural analysis validated the successful synthesis of perovskite Sr0.8X0.2Co0.2Fe0.8O3-δ (La, Ce) cathode materials with no prominent secondary phase of impurities while surface morphology revealed a porous and well-connected network of particles. EDS confirmed the composition and thermo-gravimetric analysis showed weight losses related to the creation of vacancies. The functional groups were investigated through FTIR and the conductivity measurements revealed higher electrical conductivity for Sr0.8X0.2Co0.2Fe0.8O3-δ (x = La, Ce) synthesized with orange juice as a chelating agent with Sr0.8La0.2Co0.2Fe0.8O3-δ exhibiting slightly higher value compared to Sr0.8Ce0.2Co0.2Fe0.8O3-δ. The electrochemical performance showed the highest power density of 354 and 313 mW·cm−2 at 700 °C obtained for cells having Sr0.8X0.2Co0.2Fe0.8O3-δ (x = La, Ce) cathodes synthesized with orange juice which was attributed to better crystallinity and uniform lattice. This work shows that a novel semi-organic route is successfully employed to synthesize the perovskite cathode materials for IT-SOFCs.

Hydrogen and methane as secondary fuels in diesel engines can be promising solutions to meet energy demand. The current study investigated the effect of the specialty gases of different compositions on diesel engine performance and exhaust gases. Four gases with various compositions of exhaust gas recirculation (Carbon monoxide, Carbon dioxide, and Nitrogen) and fuels (Hydrogen and Methane) were used at various mass flow rates of 10, 20, and 25 LPM (liter per minute), and various engine speeds of 2000, 2500, 3000, and 3500 rpm (revolutions per minute). The procured results revealed that adding specialty gases improved brake thermal efficiency and power. Similarly, the brake-specific fuel consumption was also massively retarded compared to diesel due to the influence of the hydrogen and methane composition. However, the fuel with the higher nitrogen reported less BTE (brake thermal efficiency) and comparatively higher exhaust gas temperature owing to the higher presence of nitrogen in their composition. Regarding emissions, including exhaust gas recirculation dropped the formation of pollutants efficiently compared to diesel. Among various fuels, Case 1 (30 % H2, 5 % CH4, 5 CO2, and 60 % CO) reported the lowest emission of NOx, and Case 2 (25 % H2, 5 % CH4, 5 CO2, 30 % CO, and 35 % N2) of CO and CO2 emissions. Generally, specialty gases with a variable composition of exhaust gas recirculation gases can be a promising sustainable replacement for existing fossil fuels.

Hydrogen fueled parallel wall-jet combustion is considered to be one of the most promising drag reduction technologies in supersonic combustors, researchers mainly focus on its drag reduction mechanism, while balancing its combustion efficiency and drag reduction performance is of great significance for engine performance and energy conservation. In this paper, combustion performance of hydrogen fueled parallel wall-jet is numerically investigated. Kinetic reaction rate and scalar dissipation rate are defined to decouple the chemical reaction and mixing processes. Results indicate that although hydrogen fueled parallel wall-jet combustion is a nonequilibrium chemical reaction process, the combustion process is dominated by mixing due to the much larger magnitude order of kinetic reaction rate. The investigation also reveals that, compared to the effects of mainstream total temperature, mainstream Mach number presents a more significant effect on combustion efficiency. Moreover, combustion efficiency increase first brings negative and then brings beneficial effects on drag reduction performance, which is due to the different sensibilities of the two skin friction determinants viscosity and velocity gradient to combustion efficiency. It is found that, viscosity is more sensitive to combustion efficiency, with combustion efficiency increases by 5.4 %, viscosity increases by 4.15 %, while velocity gradient only decreases by 2.19 %.

This paper investigates the enrichment of gold through combustion and ash-leaching techniques utilizing woody biomass as a fuel source. It delves into the formation of gold in ashes derived from the fixed grate combustion of pelletized woody biomass containing noble metals, conducted at a pilot-scale boiler. The biomass sample was gathered from a brownfield land at an abandoned mining area, avoiding induced phytoextraction. The fuel contained

The investigation of engines with different performances driving the same load-consuming device is necessary for practical applications. In this paper, three diesel engines with varying capacities for driving the same firefighting pump for high-rise residential buildings were studied and compared for their performance, combustion parameters, and emissions by the simulation method. The AVL BOOST software is utilized to establish theoretical combustion models for these engines. The operating balance point of each engine is determined, and the appropriate transmission ratio of the drive train system is proposed to be applied. The results show that the working partial load modes of Model 1 at 91 % engine load and 2970 rpm, Model 2 at 74 % engine load and 2960 rpm, and Model 3 at 57 % engine load and 2490 rpm. The engine works in its higher load mode, producing higher brake specific fuel consumption (BSFC), higher NOx and CO emissions, lower soot formation, and vice versa. The engine operates at its lower load, resulting in decreased BSFC, less NOx and CO emissions, and more soot generation. The results suggest that Model 2 in the present work is the option that can balance the factors of engine power, initial investment cost, fuel consumption economics, and emissions. The findings obtained from this work are the scientific foundations to support the design of the firefighting pump systems when considering comprehensive factors of technical technology, investment cost, and environmental consideration.

The availability of crude oil and petroleum products has become scarce and costly over the years leading to a stiff rise in engine fuel. Due to the depletion of conventional fuels; alternative fuels are gaining importance in recent times and Waste Cooking Vegetable Oils (WCVOs) are the viable option for the same. The present study highlights the performance, emission, and combustion characteristics of the Variable Compression Ratio (VCR) engine using three varieties of WCVOs (Ground Nut (GDN), Palm (PM), and Sunflower (SF)). Their inferior fuel features (density, viscosity, calorific value, etc.) are enhanced by blending 30 % of these oils with 70 % Diesel. The experiments are then conducted in the VCR engine using these blended oils under varying loading conditions (0–8 N) and at a constant speed of 1500 (RPM) with a compression ratio (18:1). It is seen that a single blend of Palm oil (PM) increases the engine Brake Thermal Efficiency (BTE) by 5 % in comparison to Diesel and other blended fuels (GDN, SF) owing to its lower calorific value and greater viscosity. The engine Brake Specific Fuel Consumption (BSFC) decreases with the increase in load and the lower loads reduce the BSFC for WCVOs by 9–15 % compared to Diesel. Engine emissions like Carbon Monoxide (CO), Nitrogen Oxide (NOx), and Hydrocarbons (HC) are also reduced significantly (by 12–15 %) using these blended oils compared to Diesel. The surge in both the Peak Cylinder Pressure (PCP) and Heat Release Rate (HRR) is also observed using these blended fuels, especially for Sunflower. Hence, these WCVOs are an appropriate option to advance the VCR engine performance and decrease its emissions.

Hexafluorocyclotriphosphazene (HFPN) is a promising flame retardant to be applied in lithium-ion batteries (LIBs) to decrease the fire risk during the treatment of electrolyte. In this manuscript, the influence of HFPN on the combustion characteristics of LIB electrolyte was investigated, the combustion behaviors and flame retardancy of the electrolyte with or without HFPN were systematically studied by using cone calorimeter, flash point meter and a series of standard equipment, as well as self-made water spray fire extinguishing platform. The flash points of 3 kinds of control group as base solution and 3 kinds of flame-retarded electrolyte were measured and obtained by SCKB3000 closed cup automatic flash point tester. The combustion characteristics of 6 types of electrolytes were analyzed by a cone calorimeter. The heat release rate (HRR), fire growth index (FGI), fire magnitude index (FMI) and other important combustion parameters of the electrolytes were studied. Based on the self-made water mist fire extinguishing platform, the fire extinguishing effect on 6 kinds of electrolytes under the same water mist condition was compared, and the influence of flame retardants in the fire extinguishing process was analyzed. The results showed that the change of flash point was obviously related to the composition of electrolyte. Flame retardant could reduce the peak HRR (pHRR) during electrolyte fire to a large extent, while it could also prolong the combustion duration of electrolyte pool fire. Under the action of fine water mist, the electrolyte pool fire would quickly extinguish, but there would remain a lot of smoke.

A numerical study was conducted to investigate the effects of hydrogen and scavenging air temperature (SAT) on the combustion and emission characteristics of a 2-stroke heavy-duty dual-fuel (DF) marine engine at full load. The engine had a 700 mm bore fuelled with hydrogen–methane (H2-CH4) mixtures. Three-dimensional simulations of the combustion and emission formation inside the engine cylinder with various H2 contents in the H2-CH4 mixture were performed. ANSYS FLUENT simulation software was used to analyse the engine performance, in-cylinder pressure, temperature, and emission characteristics. The CFD models were validated against the measured data recorded from the engine experiments. The results showed that an increase in the in-cylinder peak pressure increased the engine power when the H2 content in the H2-CH4 mixture increased. Notably, CO2 and soot emissions decreased (up to more than 65%) when the H2 content in the gaseous mixture increased to 50%. Specific NO emissions in the DF modes were lower than that of the diesel mode, when the H2 content in the gaseous mixture was lower than 40%. However, they increased compared to the diesel mode when the H2 content continued to increase. This limits the H2 amount that should be used in a gaseous mixture creating NO emissions. The results also showed that the SAT cooling method can further reduce emission problems while enhancing engine power. In particular, reducing the SAT to 28 °C in the gaseous mixture with 10% H2 ensured that the DF mode emitted the lowest NO emissions compared to the diesel mode. This reduced NO emissions by 37.92% compared to the measured NO emissions of the research engine (a Tier II marine engine). This study successfully analysed the benefits of using an H2-CH4 mixture as the primary fuel and the SAT cooling method in a 2-stroke ME-GI heavy-duty marine engine.

Briquettes uptake continues to be low, despite their ability to offset the negative impacts caused by firewood/charcoal. Possible reason for this is lack of literature towards key parameters of the developed briquettes. In the current study, emissions, combustion, kinetics and thermodynamic characteristics of rice husks agricultural residue carbonized briquettes were obtained. The water boiling test and emissions monitoring system for CO, CO2 and PM2.5were used to determine fuel and energy consumption, thermal efficiency and emissions while thermogravimetric analysis was utilized in obtaining combustion, kinetic and thermodynamic parameters. The activation energy was determined by employing four different model-free methods. Drop strength and particle density of the briquettes were 67.8% and 548.15kg/m3, respectively. Briquettes‘ moisture, volatile matter, ash content and fixed carbon were 7.2%, 16.6%, 47.4% and 28.8% respectively. Average activation energy attained by the developed briquettes by Kissinger–Akahira–Sunose, Ozawa–Flynn–Wall, Starink and Tang methods were 78.3kJ/mol, 83.3kJ/mol, 78.7kJ/mol and 75.0kJ/mol, respectively. Low energy barrier (5.2kJ/mol) between activation energy and enthalpy changes indicated that initiation occurs easily. The obtained thermodynamic parameters indicated that the thermal degradation process was endothermic in nature. High energetic densities (10,688.9MJ/m3) and Fuel Value Indices (255.5MJ/m3⋅%) were attributable to the higher heating value of the developed briquettes (19.5MJ/kg).

Rapid depletion of conventional fossil fuels and increasing environmental concern are demanding an urgent carry out for research to find an alternate fuel which meets the fuel demand with minimum environmental impacts. Hydrogen is considered as one of the important fuel in the near future which meets the above alarming problems. Hydrogen–gasoline dual fuel engines use hydrogen as primary fuel and gasoline as secondary fuel. In this review paper, the combustion performance, emission, and cyclic variation characteristics of a hydrogen–gasoline dual fuel engine have been critically analyzed. According to scientific literature, hydrogen–gasoline dual fuel engines have a good thermal efficiency at low and partial loads, but the performance deteriorates at high loads. Hydrogen direct injection with gasoline port fuel injection is the optimum configuration for dual fuel engine operating on hydrogen and gasoline. This configuration shows superior result in mitigating the abnormal combustion, but experiences high NOxemission. Employing EGR showed a maximum reduction of 77.8% of NOxemission with a EGR flowrate of 18%, further increment in flowrate leads to combustion instability. An overview on hydrogen production and carbon footprint related with hydrogen production is also included. This review paper aims to provide comprehensive findings from past works associated with hydrogen–gasoline dual fuel approach in a spark ignition engine.

At present, hydrogen is considered as one of the most promising motor fuels capable of replacing traditional hydrocarbons. This article presents the results of a comprehensive experimental study of the effect of hydrogen additives on the main parameters of a gasoline spark-ignition ICE. The thermophysical parameters of the processes of ignition and combustion inside the cylinder with the addition of hydrogen in the amount of 0%–20% of the air volume, as well as the fuel and energy characteristics of the engine and its impact on the environment, were studied. It has been established that hydrogen leads to significant changes in the engine operation. It increases some parameters and reduces others, improving or worsening them compared to running on pure gasoline. So, with a 20% H2addition at an average engine load, the following parameters increase: the maximum pressure in the cylinder by almost 20%; the rate of pressure increase in the combustion chamber by 2.8 times; the highest combustion temperature by 140 K. At the same time, the following parameters decrease: average indicator pressure by 18%; ignition timing by 82% (6° to TDC versus 34° for gasoline); crank angle corresponding to the maximum pressure by 32% (9.4° versus 13.9° for gasoline); crank angle corresponding to maximum temperature by 54% (17.7° after TDC versus 38.3° for clean gasoline); ignition delay time (τind=0.32ms) and visible combustion time (τvis=1.58ms) by 4 and 2.3 times, respectively.

This research explores the integration of large language models (LLMs) into scientific data assimilation, focusing on combustion science as a case study. Leveraging foundational models integrated with Retrieval-Augmented Generation (RAG) framework, the study introduces an approach to process diverse combustion research data, spanning experimental studies, simulations, and literature. The multifaceted nature of combustion research emphasizes the critical role of knowledge processing in navigating and extracting valuable information from a vast and diverse pool of sources. The developed approach minimizes computational and economic expenses while optimizing data privacy and accuracy. It incorporates prompt engineering and offline open-source LLMs, offering user autonomy in selecting base models. The study provides a thorough examination of text segmentation strategies, conducts comparative studies between LLMs, and explores various optimized prompts to demonstrate the effectiveness of the framework. By incorporating an external vector database, the framework outperforms a conventional LLM in generating accurate responses and constructing robust arguments. Additionally, the study delves into the investigation of optimized prompt templates for the purpose of efficient extraction of scientific literature. Furthermore, we present a targeted scaling study to quantify the algorithmic performance of the framework as the number of prompt tokens increases. The research addresses concerns related to hallucinations and false research articles by introducing a custom workflow developed with a detection algorithm to filter out inaccuracies. Despite identified areas for improvement, the framework consistently delivers accurate domain-specific responses with minimal human oversight. The prompt-agnostic approach introduced holds promise for future improvements. The study underscores the significance of integrating LLMs and knowledge processing techniques in scientific research, providing a foundation for advancements in data assimilation and utilization.

TiAl is used as the preferred material for aero-engine low-pressure turbine blades, which is also faced with similar problems of “Titanium fire” under long-term high temperature service conditions. In this paper, the micro-combustion behavior of TiAl is discussed. It is found that the flame-retardant of the TiAl alloy has better performance compared to that of TC11, TA11. In this regard, the higher content of Al and Nb is identified as the primary reason for the superior flame-retardant performance for TiAl alloy. Moreover, the segregation serves as a transport channel for atoms and entraps oxygen atoms during the process of extended combustion. The three-stage combustion model before deflagration is presented. Furthermore, the flame-retardant mechanism before and after deflagration is explained, highlighting the main reason behind the formation of the final morphology of the alloy after combustion.

In this study, single-walled carbon nanotubes (SWCNT) and double-walled carbon nanotubes (DWCNT) were separately added to diesel fuel to investigate their effects on the combustion, performance, and emission characteristics of a diesel engine. SWCNT and DWCNT were added to diesel fuel at concentrations of 100 mg/L with the assistance of ultrasonication, resulting in the creation of DFCNT-1 and DFCNT-2 fuels. Fuel samples were tested at 1500 rpm under varying load conditions. The results indicated significant increases in combustion parameters such as cylinder pressure (CP), Net Heat Release Rate (NHRR), Rate of Pressure Rise (ROPR), Cumulative Heat Release (CHR), and average gas temperature (MGT) for DFCNT-1 and DFCNT-2 fuels. Additionally, the use of DFCNT-1 and DFCNT-2 fuels led to a decrease in carbon monoxide and smoke emissions while nitrogen oxide and carbon dioxide emissions increased. The Brake Specific Fuel Consumption (BSFC) decreased by 7.59% and 4.29% with the use of DFCNT-1 and DFCNT-2, respectively. Moreover, a shorter ignition delay (ID) and combustion duration (CD) were observed with DFCNT-1 and DFCNT-2 fuels. Overall, it was concluded that the addition of SWCNT was more effective than DWCNT in terms of combustion efficiency, performance, and emissions.

An oxygen-rich and low NOx burner integrated with liquefied natural gas (LNG) was proposed to address unstable combustion and high NOx emissions from a 330 MW subcritical boiler under ultra-low load operation in China. To assess the effectiveness of the retrofit, Chemkin and Fluent softwares were utilized to construct a new NOx model and calculate NOx generation, based on the combustion of pulverized coal gas and LNG. Further, an eddy dissipation concept (EDC) model, which can reflect detailed chemical reactions, was applied to calculate gas-phase reactions in the furnace. The results showed that when performing the deep peak shaving after the retrofit, the combustion in the furnace was stable under 50% or more load, and NOx emission level at the furnace outlet was lower than 350 mg/m3 (6% O2 content, dry basis). Under 25% load, the oxygen-rich burner integrated with LNG was applied, and the pulverized coal flow entered the furnace in a state of high-intensity combustion, which effectively promoted the stability of combustion in the furnace. The reductive combustion state with reductive free radicals generated by LNG decomposition inhibited NOx formation. Consequently, NOx emissions from the furnace outlet decreased from 380 mg/m3 to 316 mg/m3.

Morocco is the world's 5th largest olive oil producer with 160,000 tons in 2020/2021 and the production of 1 L of olive oil generated approximately 5 kilos of waste olive cake, this type of waste is dangerous for the environment and especially for groundwater. To address this issue and take into account the thermal properties of olive waste, our project's goal is to produce power and heat by using solid olive waste in a Stirling cogeneration system. Therefore, the goal of this article is to examine by using CFD tools the environmental impacts of the Moroccan solid olive waste burning in a CHP (combined heat and power) unit. The idea is to integrate a smart renewable energy system based on olive cake and the Stirling motor to produce electricity in order to employ this electrical energy for water pumping in rural areas.The impact of the excessive air ratio on temperature profile and exhaust has been investigated and discussed. In addition, the pollutant species in air has been presented, and compared with guideline values given by some international organization for health and environment. Results show that the highest excess air ratio gives high temperatures with a homogeneous distribution around the Stirling motor hot heat exchanger, and minimum emissions of CO, CO2, NO, NO2 and NH3 that do not exceed the values set by WHO, OSHA, and NIOSH.

Ammonium perchlorate (AP) serves as a crucial component in solid propellants. Enhancing its thermal decomposition with catalysts improves the combustion performance of solid propellants significantly. To enhance the catalytic performance of metal-organic frameworks (MOFs) on AP, this study controlled the morphology of MOFs by adding metal atoms, resulting in a Fe-Co-MOF catalyst with higher specific surface area and dual-metal synergistic effect. The catalytic effect of the catalyst on AP was investigated using DSC and TG-IR, followed by studying its influence on the combustion performance of AP-based composite propellants. The results show that the introduction of 5% Fe-Co-MOF reduced the decomposition temperature of AP to 298.6 °C, decreased the activation energy to 151.6 kJ mol-1, and increased the heat release by 110.6%. Additionally, the ignition delay of the propellant decreased by 71 ms, and the combustion rate increased by 43.8%. Mechanistic studies demonstrate that the abundant catalytic sites and oxygen vacancies of Fe-Co-MOF facilitate the charge transfer rate during the AP thermal decomposition process and promote the increase in AP heat release by suppressing the high-temperature conversion of N2O. This research paves the way for enhancing the application of MOF materials in AP-based solid propellants.

The formation of the gas mixture in the cylinder has a significant effect on the combustion and emission of the engine. The main difference between a conventional engine and a free piston engine is that the piston movement mode is different. Therefore, a new coupled iterative method is adopted in this paper to study the injection position and duration of hydrogen fuel in a free piston engine where diesel fuels hydrogen, and reveal its influence on gas mixing and combustion in the cylinder of a free piston engine. The results show that it is suitable to spray hydrogen 55 mm from TDC. At this time, the mass fraction of H2 in the cylinder is relatively uniform, the cumulative heat release is about 620 J, and the pressure and temperature are relatively low, which are 7.2 MPa and 1529 K respectively. The duration of hydrogen injection is 0.4 ms, at this time, the mixing degree in the cylinder and the gas flow speed are better, although there is a little shortage of unburned equivalent ratio, but this has little impact on the overall, and the final cumulative heat release reaches 655 J.

Low-pressure gas-admission marine two-stroke engines have significant potential for reducing emissions in the shipping industry. However, they exhibit poor combustion quality under low-load conditions, leading to lower thermal efficiency and high levels of HC and CO emissions. This study numerically evaluated the impacts of the gas admission location and timing on engine performance and exhaust gas emissions under low load conditions. The study revealed that different gas admission locations form distinct NG-air stratifications. Lower gas admission locations resulted in longer ignition delays and shorter combustion durations. The unburned CH4 and CO emissions were significantly reduced by a maximum of 20.14% and 42.29%, respectively. A trade-off exists between NOx and N2O emissions owing to the different temperature conditions of their formation. The NOx emissions increased continuously as the gas admission location was lowered to a maximum of 3.4218 g/kWh; a value slightly above the Tier III emission standards. Advancing the timing of gas admission further decreased the ignition delay time, NOx, and unburned CH4 emissions. This study revealed that in-cylinder natural gas mixture stratification due to varying gas admission locations and timings can improve the combustion efficiency and exhaust gas emissions of a natural gas-diesel dual-fuel engine under low-load conditions.

Biomass gasification with steam injection in a fluidized bed reactor has emerged as a promising method to improve syngas quality by increasing hydrogen production. In this work, a simplified yet comprehensive three-dimensional multiphase model incorporating combustion chemistry and heat transfer was integrated into AVL FIRE CFD software through the implementation of user-defined subroutines. Biomass combustion and gasification for four different bed materials acting as catalysts to the biomass pyrolysis process with steam injection were investigated for this work. Beechwood was consistently used as the biofuel for all the experiments while varying the bed material. Four various types of bed materials (Silica sand, Olivine, Na–Y Zeolite, and ZSM-5 Zeolite) were used in the study and a constant steam injection was maintained. ZSM-5 Zeolite exhibited the highest hydrogen production under steady-state condition. The present model was validated against experimental results available in the literature for a lab-scale fluidized bed reactor. The model's results of species concentrations of the syngas were analyzed and compared with the experimental results and found reasonable similarity.

Solid fuels are relatively inexpensive and widely available, making them an attractive option for energy producers. However, they are currently inefficient in converting heat energy into electricity, and new technological advances are needed to make them more efficient. Plasma ignition and stabilization of pulverized coal flame provides a cost-effective and sustainable approach to boiler start-up and combustion stabilization, avoiding the traditionally used fuel oil or gas. This technology consists of heating the air-coal mixture with electric arc plasma to the temperature of coal devolatilization and partial gasification of the coke residue. Thus, a highly reactive two-component fuel, consisting of combustible gas and coke residue, is obtained from the original coal. In this paper, a comprehensive thermodynamic and kinetic analysis was carried out. A thermodynamic analysis was carried out to study the optimal parameters of plasma ignition and stabilization of combustion of a pulverized fuel flame. Kinetic modeling of the process of plasma ignition and stabilization of combustion of pulverized fuel made it possible to obtain changes in temperatures, velocities and concentrations of high-temperature two-component fuel components along the length of the plasma-fuel system. In experiments on plasma ignition of thermal coal, a stable coal-dust flame was obtained, and its temperature, composition and degree of carbon gasification were determined. Comparison of experimental and calculated data showed satisfactory agreement.

This study focuses on alternatives to the sustainable management of plastic wastes through the development of a pyrolyser model, adapted to the recycling of plastics into fuel. It is a batch reactor, fixed bed, designed and built for the extraction of pyrolysis oil that can be recycled into petrol or diesel. The pyrolyser consists of a reactor with a volume of 0.0424 m3 and a copper spiral condenser with 2.31 m length. The plastics used for this study were Low Density PolyEthylene (LDPE), polypropylene (PP), polystyrene (PS) and polyethylene terephthalate (PET). They were collected from surrounding companies, washed, sampled, cut and sieved. Two different sizes of pyrolysis material: 1–3 cm (G1) and 3–7 cm (G2) were obtained and tested. The pyrolysis reactor and the plastics entering at an ambient temperature of 25 °C were heated. Plastics were then melted at 110 °C and vaporised at 450 °C. The hot vapour produced circulated through a copper coil and condensed. The resulting liquid was called pyrolysis oil. The results of this study show that the pyrolysis of LDPE, PP and PS yields two liquids: the heavy and majority fraction which arelike the conventional diesel and the light fraction which is like gasoline. Yields of 6–12.4% for the light fraction and 43.2–63.8% corresponding to the heavy fraction are observed. PE has the highest yield, 63.8% for the heavy fraction and 12.4% for the light fraction. The study further underscores that the size of the pyrolysis material influences the yields, i.e. an increase of 12.5, 9.1 and 7 % for LDPE, PS and PP respectively when the size of the pyrolysis material is increased from G2 to G1. In contrast, the results of PET have shown a liquid that solidifies 46 s later. It was also noticed that 2061.34 kJ of energy was required to pyrolyse 1 kg of plastic and produce 0.762 l of fuel. The simple physico-chemical characterisation of the majority fraction shows a great similarity with diesel fuel, as the distillation went beyond 200 °C. Therefore, we can say that the diesel fraction is similar to diesel fuel. We equally observed a high cetane number (52.1–55.1) and a high calorific value (42.9–55.5 MJ/kg). Consequently, there are some points of non-conformity with the European 590 standard and Cameroonian specifications for diesel fuel. These include a low density (767.8–815.1 kg/m3) and a low viscosity at 40 °C (1.108–1.346 mm2/S). A thorough physico-chemical analysis will complete this study before any recommendation for appropriate use.

Nanosizing and alloying of aluminum (Al) promisingly improve ignition and combustion performance of Al-based propellants. To aim this, lased-induced ignition and combustion characteristics of micro/nano-Al and aluminum@nickel (Al@Ni) alloy powders at elevated pressures (0.1–3.0 MPa) were investigated and the pressure effect on these characteristics was correspondingly evaluated. Comparative results demonstrate that nanosizing and alloying significantly shorten ignition delay and total burn time at elevated pressures, with ignition delay reduction of 98.04% and 52.28% at 1.0 MPa for nano-Al and Al@Ni alloy compared to micro-Al counterpart. Nanosizing and alloying can decrease crucial pressure values (‘mid-pressure extinction domains’) influencing ignition delay, and promote the transfer from the surface to gaseous combustion mode. Maximum combustion temperatures of nano-Al are higher than micro-Al and Al@Ni alloy. During combustion, the combustion of Al@Ni alloy is further intensified due to the microexplosion, while possibly inhibited at higher pressures.

Currently, the modeling of complex chemical-physical processes is drastically influencing industrial development. Therefore, the analysis and study of the combustion process of the boilers using machine learning (ML) techniques are vital to increase the efficiency with which this equipment operates and reduce the pollution load they contribute to the environment. This work aims to predict the emissions of CO, CO2, NOx, and the temperature of the exhaust gases of industrial boilers from real data. Different ML algorithms for regression analysis are discussed. The following are input variables: ambient temperature, working pressure, steam production, and the type of fuel used in around 20 industrial boilers. Each boiler's emission data was collected using a TESTO 350 Combustion Gas Analyzer. The modeling, with a machine learning approach using the Gradient Boosting Regression algorithm, showed better performance in the predictions made on the test data, outperforming all other models studied. It was achieved with predicted values showing a mean absolute error of 0.51 and a coefficient of determination of 99.80%. Different regression models (DNN, MLR, RFR, GBR) were compared to select the most optimal. Compared to models based on Linear Regression, the DNN model has better prediction performance. The proposed model provides a new method to predict CO2, CO, NOx emissions, and exhaust gas outlet temperature.

This study delves into the combustion characteristics of diesel-vegetable oil blends using an industrial fuel burner, shedding light on essential factors that impact the viability of these alternative fuels in industrial applications. Viscosity, a key concern in vegetable oil-based fuels, can be effectively mitigated by blending with diesel. This viscosity reduction enhances fuel atomization, optimizing combustion efficiency and mitigating nozzle blockages. The study also explores the density variation in these blends, indicating potential implications for combustion kinetics and injection dynamics. Furthermore, the research addresses the trade-off between energy content and viscosity reduction as the calorific value decreases with an increasing volume ratio of vegetable oil. Flame behavior, crucial for combustion system design, exhibits an inverse relationship with the volume ratio of vegetable oil, resulting in shorter and less intense flames at higher vegetable oil content. Through comprehensive experiments, the study demonstrates that increased vegetable oil content leads to reduced flame length and stability, primarily attributed to the elevated density and viscosity of vegetable oil. A comparative analysis highlights the similarity in combustion properties between a 40 % vegetable oil and a 60 % diesel blend, which exhibited a kinematic viscosity of approximately 1.58 cP emphasizing the potential of vegetable oil as a viable substitute for diesel in industrial fuel burners.

Carbon-containing compositions of refractory products with additives of aluminum, silicon, graphite of fractional composition have been developed and optimized, and their technical properties, as well as the phase-mineral composition, have been determined.An experimental setup has been developed to study temperature parameters in given hypothetical layers, calculated heat fluxes and temperature stresses of carbon containing products up to 1300 °C.Temperature stresses and specific heat flows are calculated at the heating rate of the working surface from 4.3 °C/min to 55 °C/min with isothermal exposure of products at 700 °C, 950 °C and 1300 °C.This study is devoted to the technology of obtaining carbon-containing refractories by solid-state combustion method (in SHS mode) with the maximum transformation of low-melting phases into refractory ones using ferroalloy metallurgy waste, as well as to the study of thermophysical properties, composition, and influence of specific heat fluxes on temperature stresses in conditional hypothetical layers obtained carbon-containing SHS refractory products.

To solve the problem of nano-aluminum (nAl) powder easy agglomeration and improve its thermal reaction, nAl was combined with adhesive (Viton A, F2602) and oxidizer (Ammonium perchlorate, AP) forming microspheres by electrostatic spray method. The morphology and structure were analyzed by SEM, EDS and XPS. The results showed that the microspheres (diameter≈Φ10–15 μm) were hollow structures formed by winding of fluoropolymer fibers, while AP and nano aluminum particles were embedded on the fibers. By controlling the electric spray process, the well-dispersed AP and nAl nanocrystals were assembled on the fiber. Thermal analysis indicated that the gas phase products decomposed by AP were absorbed by porous microspheres, and part of the heat was stored in polymer fibers, thus promoting the breakdown of the alumina shell and accelerating the pre-ignition reaction. The combustion and laser ignition experiments proved hollow heterogeneous microspheres have excellent thermodynamic properties. The assembled microspheres not only solved the problem of poor rheology caused by the agglomeration of nAl, but also improved the insufficient combustion of nAl and the condensation of products.

Background: E-cigarette abuse, also known as vaping, is a widespread habit. Recently, there have been increasing reports of explosions of these devices resulting in serious burn injuries, especially to the groin, hand, and face. Overheating rechargeable lithium-ion batteries are supposed to be the responsible mechanism, especially in low quality fabrications. Methods: In this single-center retrospective study, data of 46 patients are presented and analyzed. In addition to information on demographics, injury patterns, and treatment options, this is the first study investigating outcome after an average of 13 months via a standardized telephone interview of 31 patients (67%). Patients were specifically asked regarding their outcome, vaping habits, technical modifications to their devices and supply source. Results: Patients were mainly male (98.2%) with a median age of 36 years. Typical injury patterns included the groin region (n = 32; 69%), hands (n = 12; 25%) and face (n = 3; 7%). All patients underwent debridement, in nine cases hydrotherapeutically. 61% (n = 28) underwent consecutive tangential necrectomy and subsequent split thickness skin graft transplantation. Wound infection was observed in 18 patients (39%), with burn depth as a significant risk factor (p < 0.001). 91% of the followed-up patients were satisfied. Surprisingly, 38% were still using e-cigarettes. 42% (n = 13) reported manual modifications of their devices to prolong battery life or increasing smoke production. Conclusions: Injuries from exploding e-cigarettes can be serious and should be treated in a specialized burn center. E-cigarette explosions lead to characteristic injury patterns and often need surgical treatment. This should be made more public to reduce their use and keep people from modifying the devices. The counterintuitive and irrational observation of a high rate of abuse even after the injury underlines their addiction potential.

Mixing of fuel and air is important for improving combustion performance and reducing pollution emissions. To improve the mixing performance of gaseous methane and air, the typical flame stabilizer was modified. A numerical study was conducted to compare the mixing and combustion performance of the mixing-enhanced flame stabilizer with the original one, and the mixing enhancement mechanism was clarified. The results show that the mixing performance of the mixing-enhanced flame stabilizer is improved in two ways. On the one hand, the disturbance of the gas fuel jet in the recirculation zone promotes the mixing of fuel and air. On the other hand, the velocity gradient between the recirculation zone downstream the bluff body and the mainstream decreases, which allows more fuel to enter the recirculation zone downstream the bluff body. This study is expected to promote the rapid mixing of gaseous fuel jets and the flame stability of the combustion chamber based on bluff body stabilizers.

Composite propellants are used to fabricate solid motors for space vehicles. The fundamental factor that affects motor safety is the structural damage in the propellant owing to slow heating in an abnormal storage or service environment. Hence, their thermal damage and combustion characteristics should be studied comprehensively. In this study, we investigated the combustion behaviours of hydroxyl-terminated polybutadiene/ammonium perchlorate/aluminium powder (HTPB/AP/Al) and hydroxyl-terminated block copolyether/AP/Al (HTPE/AP/AI) propellants under slow heating conditions. The pore structure was observed using scanning electron microscopy and micro-computerised tomography. Their weight loss behaviour, gaseous products, and pore structure evolution were analysed using thermogravimetric analysis, mass spectrometry, and Fourier-transform infrared spectroscopy. The influence of the pore structure on the combustion behaviour was studied by establishing the relationship between combustion and energy release rates. The weight loss rates of HTPB/AP/Al and HTPE/AP/Al before ignition were 34.5% and 16.1%, respectively. Upon heating, the HTPB binder decomposed to form pore channels, through which the gaseous products produced from the decomposition of AP were released, which increased the structural damage in this propellant. In contrast, upon heating, the HTPE binder liquefied and formed a coating on the AP particles, which slowed the structural damage in this propellant. Moreover, the calculated reaction intensity of HTPB/AP/Al was 4.16 times that of HTPE/AP/Al, indicating that larger pore channels increase the burning surface for combustion.