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The natural convective Cu-water nanofluid flow in l-shape cavity with an oscillating temperature profile is studied numerically. The cavity's lower horizontal and left vertical walls are heated sinusoidally with time about a high mean temperature (T¯H). In contrast, the cavity's right vertical wall and its nearby horizontal lower wall are kept cold at a temperature (Tc). The calculations have been performed over temperature oscillation amplitude (0≤A≤2), dimensionless temperature oscillation frequency 0≤f≤100, Rayleigh number (103≤Ra≤108), Hartmann number (0≤Ha≤100), the nanoparticles volume fraction (0≤ϕ≤0.2), and enclosure aspect ratios (0.2≤AR≤0.8). Outcomes reveal that with AR = 0.2, heat transfer happens considerably through conduction at Ra = 103 –105, while the time average Nusselt number (Nu¯) is independent of both Ha and Ra. Convection effects, on the other hand, become significant at high Ra. Additionally, as Ha ascends from 0 to 50, Nu¯ increases linearly with increasing ϕ, while it remains steady at Ha = 75 and 100.

A thermodynamic model was developed for combustion, performance, and emissions with a reference diesel fuel, a 10 vol% methanol blend with 90 vol% diesel, a 10 vol% ethanol with 90 vol% diesel and a 4% hydrogen fumigating in the inlet port along with diesel direct injection. The diesel and two alcohol blends (10% methanol–90% diesel, and 10% ethanol–90% diesel) was directly injected into the cylinder, while hydrogen was fumigated at the inlet port. The model was developed by commercial GT-Suite software. Besides engine performance, exergy and energy rates were estimated for the four fuels. Among the four fuels/fuel blends, hydrogen fuel (4% fumigated hydrogen) shows the best performance in terms of exergy, energy rates, specific fuel consumption, power, and greenhouse gas emissions. Regarding greenhouse gases, carbon dioxide was only considered in this investigation as it contributes to a significant detrimental effect on environmental pollution.

A comprehensive fuel property using neat diesel, neat tire (100% tire oil after distillation of crude tire oil from pyrolysis process) oil, diesel–tire oil blend and diesel–tire oil–biodiesel blends were investigated in this study. The tire oil was derived from waste tire by pyrolysis process at a temperature of 450 °C. The tire oil was upgraded by the fractional distillation process. Different proportions (10 vol% and 20 vol%) of waste tire oil were mixed with a reference diesel fuel. Various ratios, including 10 vol% and 20 vol% biodiesel was blended with waste tire oil and waste tire oil–diesel blends to examine the fuel properties with a target to use the different fuel blends as compression ignition (CI) engine’s fuel. A novel pumpkin seed oil (Cucurbita pepo) biodiesel was chosen due to its abundant availability and renewable nature. The reason for blending pumpkin seed oil–biodiesel is to improve the waste tire oil fuel properties and investigate the influence of fuel oxygen on different fuel properties. Binary blends, including tire oil–diesel, tire oil–biodiesel, and ternary blends, including diesel–tire oil–biodiesel, were prepared for the tests. The properties tested in this investigation were density, viscosity, higher and lower heating value, smoke limit, flash point, fire point, aniline point, pour point, cloud point, cetane number, sulphur and carbon residue, proton nuclear magnetic resonance (1H NMR), Fourier transform infra-red (FTIR) spectroscopy and elemental analysis (CHONS). The comprehensive fuel property results showed that all binary and ternary blends show similar properties compared to reference diesel. Although the binary blends of tire oil and biodiesel indicate a little inferior property than reference diesel fuel, they can be used as fuels for compression ignition engines.

This study aims to develop a one-dimensional model to investigate the effect of hydrogen share in gasoline fuel on the performance, combustion, and exhaust emissions of a gasoline direct-injection engine. Iso-octane was used as a reference fuel to compare performance, combustion, and emission parameters. The model was developed using commercial GT-Suite and ANSYS software. The simulation results using GT-Suite were validated with the published data and ANSYS results. The hydrogen fractions were varied from 0% to 11.09% to validate the simulation results with the published results. The investigation continued with three higher hydrogen fractions (15%, 20% and 25%) to study the performance, combustion, emissions, and sustainability parameters. Compared to neat gasoline, hydrogen-shared fuels show a maximum 2% higher exergy efficiency, 51% higher exergy and 42% energy rates while reducing carbon dioxide (CO2) emissions by 51% with a penalty of nitrogen oxide emissions (NOx) by 62% at an excess ratio of 1.3. Other novel findings, including higher sustainability indices, lower depletion potentials, and lower unitary cost indices with higher-fraction hydrogen fuels, suggest that they are environmentally and economically sustainable. In the second part of this study, the NOx formation mechanism and its associated factors, including in-cylinder temperature, heat transfer rate, cumulative heat release, and burned rate, were confirmed and compared with gasoline and neat ethylene.

This work investigated engine performance and emissions using waste tire oil-diesel-biodiesel blends. A sustainable fuel glycine max biodiesel was blended with the tire oil-diesel blends to improve performance, combustion, and exhaust emissions. The seven fuels including a 100% diesel 10–30% waste tire oil to 90-70% diesel, 10% tire oil +10% biodiesel +80% diesel, 30% tire oil+10% biodiesel+60% diesel and 10% biodiesel+90% diesel was used as fuels in a direct injection diesel engine. Up to 30% (vol) waste tire pyrolysis oil was blended with diesel. More than 30% of waste tire pyrolysis oil shows inferior solubility issues and inferior engine performance and emissions. Thus, this investigation was limited to 30% waste tire pyrolysis oil. All fuel blends showed similar properties to diesel. With similar engine performance, like torque, power, efficiency, energy, and exergy metrics, the blends showed insignificant variations in emissions (carbon dioxide, nitrogen oxide) compared to a reference diesel fuel. Interestingly, the experimental results were compared with the modelling results, and the maximum variations between them were 10%. The outcome of this research can promote waste tire pyrolysis oil as an alternative fuel for diesel engines and accords with alternative energy development initiatives all over the world.

A large percentage of solar energy is converted to accumulated thermal energy leading to temperature rise in the PV panel. The raised PV surface temperature could be utilized for fluid heating. The objective of the current work is to integrate the PV panels with an inclined solar chimney and carry out an experimental and numerical assessment of the developed hybrid system. An experimental model comprises a solar collector with a photovoltaic panel as an absorber, a chimney, and a convergent nozzle has been developed. A Series of measurements have been carried out at various weather conditions. A numerical simulation predicted the airflow and heat transfer characteristics utilizing ANSYS fluent software to extend the analysis and evaluation of the hybrid system. Results showed that the hybrid system produces power within a range of 9% to 11% efficiency, which is approximately two orders of magnitude higher than the typical solar chimney efficiency. In contrast, it increased by 18% compared to the stand-alone PV panel. A minor increase in output power with a negligible decrease in LCOE was expected to increase the size further.