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The head-on collision of drops is governed by the interfacial tension, viscosity, and inertia of the impacting drops. Earlier studies show that depending on the relative magnitude of these forces, the outcome of a head-on collision of two identical drops of the same liquid is likely to culminate in coalescence or reflexive separation. In this study, the head-on collision of drops of miscible liquids having dissimilar viscosity has been investigated numerically. As the two drop liquids are miscible, it is anticipated that the average viscosity of the two liquids will replicate the transition boundaries of coalescence and reflexive separation for a single fluid. However, numerical simulations reveal that this is true only for low-viscosity ratios. A high-viscosity ratio creates asymmetric flow; hence, the average viscosity does not accurately represent the local viscous effect. The asymmetric flow also facilitates the pinch-off of a thread without the separation of a satellite. The present investigation reveals that viscosity contrast leads to two additional outcomes of the head-on collision of drops: encapsulation and crossing separation. We have built a phase diagram identifying the outcome of a head-on collision of dissimilar viscosity drops on the viscosity ratio (µr)-Weber number (We) plane based on the results of approximately 450 simulations.
RESUMEN
Dwindling of fossil fuels and the global climate change has prompted civilization to look into alternate energy sources. This has led to explore inexhaustible and sustainable resources in the domain of renewable energy. Among all sources renewable energy, biofuel produced from biomass has great prospect for energy security as well as environmental safety over fossil fuels. The present work tries to explore the performance attributes and emission characteristics of a CI engine utilizing spirulina microalgae biodiesel blend comprising of 20% algae biodiesel blended with 80% diesel. This blend is tested in a diesel engine at varying engine load conditions of 20%, 40%, 60%, 80%, and 100% at variable injection timing of 20°, 23°, 25°, and 28° bTDC, respectively at compression ratio of 18. Based on experimental results, the peak brake thermal efficiency for injection timing of 20°, 23°, 25°, and 28° bTDC at 100% engine load were observed to be 26.79%, 23.77%, 24.77%, and 25.09%, respectively for the biodiesel blend in comparison to 27.76% of diesel mode whereas the emissions levels were found to minimum at 20° bTDC. On the part of emission, the average drop in CO emissions for injection timing of 20°, 23°, 25°, and 28° bTDC were found to be 53.46%, 43.71%, 44.34%, and 50.31%, respectively for biodiesel blend as compared to diesel mode. For the same setting, in comparison diesel mode, the average fall in HC emissions were found to be 42.32%, 34.13%, 30.37%, and 37.54%, respectively, and the rise of NOx emissions were found to be 8.06%, 5.55%, 3.51%, and 3.04%, respectively. Response surface methodology was applied for optimization of operating parameters of the algae biodiesel blend run diesel engine. The desirability based study revealed that at 85.19% engine load and injection timing of 20° bTDC were optimal operation settings which resulted in engine performance of 25.44% brake thermal efficiency. The emission level at this setting was observed to be reduced to 27.68 ppm CO, 1.60% CO2, 24.65 ppm HC, and 182.15 ppm NOx.
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Graphene's two-dimensional structural arrangement has sparked a revolutionary transformation in the domain of conductive transparent devices, presenting a unique opportunity in the renewable energy sector. This comprehensive Review critically evaluates the most recent advances in graphene production and its employment in solar cells, focusing on dye-sensitized, organic, and perovskite devices for bulk heterojunction (BHJ) designs. This comprehensive investigation discovered the following captivating results: graphene integration resulted in a notable 20.3% improvement in energy conversion rates in graphene-perovskite photovoltaic cells. In comparison, BHJ cells saw a laudable 10% boost. Notably, graphene's 2D internal architecture emerges as a protector for photovoltaic devices, guaranteeing long-term stability against various environmental challenges. It acts as a transportation facilitator and charge extractor to the electrodes in photovoltaic cells. Additionally, this Review investigates current research highlighting the role of graphene derivatives and their products in solar PV systems, illuminating the way forward. The study elaborates on the complexities, challenges, and promising prospects underlying the use of graphene, revealing its reflective implications for the future of solar photovoltaic applications.
RESUMEN
This research presents an in-depth examination that utilizes a hybrid technique consisting of response surface methodology (RSM) for experimental design, analysis of variance (ANOVA) for model development, and the artificial bee colony (ABC) algorithm for multi-objective optimization. The study aims to enhance engine performance and reduce emissions through the integration of global maxima for brake thermal efficiency (BTE) and global minima for brake-specific fuel consumption (BSFC), hydrocarbon (HC), nitrogen oxides (NOx), and carbon monoxide (CO) emissions into a composite objective function. The relative importance of each objective was determined using weighted combinations. The ABC algorithm effectively explored the parameter space, determining the optimum values for brake mean effective pressure (BMEP) and 1-decanol% in the fuel mix. The results showed that the optimized solution, with a BMEP of 4.91 and a 1-decanol % of 9.82, improved engine performance and cut emissions significantly. Notably, the BSFC was reduced to 0.29 kg/kWh, demonstrating energy efficiency. CO emissions were lowered to 0.598 vol.%, NOx emissions to 1509.91 ppm, and HC emissions to 29.52 vol.%. Furthermore, the optimizing procedure produced an astounding brake thermal efficiency (BTE) of 28.78%, indicating better thermal energy efficiency within the engine. The ABC algorithm enhanced engine performance and lowered emissions overall, highlighting the advantageous trade-offs made by a weighted mix of objectives. The study's findings contribute to more sustainable combustion engine practises by providing crucial insights for upgrading engines with higher efficiency and fewer emissions, thus furthering renewable energy aspirations.
RESUMEN
A solar water heater has been developed to convert solar radiation into heat for use in residential and commercial settings. The collector makes up the bulk of a solar water heating system. The solar energy is captured by the collector and transferred to the tube that delivers the working fluid, water. In addition to the collector's tube, which carries the working fluid, researchers have focused on the design of the collector's tube. This paper examines the performance of a parabolic plate solar water heater that uses a copper dimpled tube with aluminum-coated tube channels. During the test, the flow rate of base fluid was in the range of 1.0 to 3.0 kg/min in steps of 0.5. The performance of the solar water heater was also evaluated and verified using CFD. The test data such as friction factor, Reynolds number, uncertainty analysis, Nusselt number, solar collector efficiency, coefficient of convective heat transfer, linear dimpled tube velocity analysis, achieving maximum energy efficiency and thermal efficiency have been used to generate parametric values for parabolic plate solar water heaters. The results suggest that the best outcomes can be achieved with a mass flow rate of 2.5 kg/min and the overall thermal efficiency was raised to 31.85%, which is 11% greater than that of the plain tube with base fluid. At mass flow rates of 2.5 kg/min, the pressure drop was found to be 6.24% higher than that of 3.0 kg/min. The experimental results were analyzed and compared with the CFD results, and the overall deviation was ± 3.24% which is in the acceptable range.
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The influence of humans on the environment is growing drastically and is pervasive. If this trend continues for a longer time, it can cost humankind, social and economic challenges. Keeping this situation in mind, renewable energy has paved the way as our saviour. This shift will not only help in reducing pollution but will also provide immense opportunities for the youth to work. This work discusses about various waste management strategies and discusses the pyrolysis process in details. Simulations were done keeping pyrolysis as the base process and by varying parameters like feeds and reactor materials. Different feeds were chosen like Low-Density Polyethylene (LDPE), wheat straw, pinewood, and a mixture of Polystyrene (PS), Polyethylene (PE), and Polypropylene (PP). Different reactor materials were considered namely, stainless steel AISI 202, AISI 302, AISI 304, and AISI 405. AISI stands for American Iron and Steel Institute. AISI is used to signify some standard grades of alloy steel bars. Thermal stress and thermal strain values and temperature contours were obtained using simulation software called Fusion 360. These values were plotted against temperature using graphing software called Origin. It was observed that these values increased with increasing temperature. LDPE got the lowest values for stress and stainless steel AISI 304 came out to be the most feasible material for pyrolysis reactor having the ability to withstand high thermal stresses. RSM was effectively used to generate a robust prognostic model with high efficiency, R2 (0.9924-0.9931), and low RMSE (0.236 to 0.347). Optimization based on desirability identified the operating parameters as 354 °C temperature and LDPE feedstock. The best thermal stress and strain responses at these ideal parameters were 1719.67 MPa and 0.0095, respectively.