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In this paper, 3D Simulation of turbulent Fe3O4/Nanofluid annular flow and heat transfer in sudden expansion are presented. k-ε turbulence standard model and FVM are applied with Reynolds number different from 20000 to 50000, enlargement ratio (ER) varied 1.25, 1.67, and 2, , and volume concentration of Fe3O4/Nanofluid ranging from 0 to 2% at constant heat flux of 4000 W/m2. The main significant effect on surface Nusselt number found by increases in volume concentration of Fe3O4/Nanofluid for all cases because of nanoparticles heat transport in normal fluid as produced increases in convection heat transfer. Also the results showed that suddenly increment in Nusselt number happened after the abrupt enlargement and reach to maximum value then reduction to the exit passage flow due to recirculation flow as created. Moreover the size of recirculation region enlarged with the rise in enlargement ratio and Reynolds number. Increase of volume Fe3O4/nanofluid enhances the Nusselt number due to nanoparticles heat transport in base fluid which raises the convection heat transfer. Increase of Reynolds number was observed with increased Nusselt number and maximum thermal performance was found with enlargement ratio of (ER=2) and 2% of volume concentration of Fe3O4/nanofluid. Further increases in Reynolds number and enlargement ratio found lead to reductions in static pressure.

Practical applications such as solar power energy systems, electronic cooling, and the convective drying of vented enclosures require continuous developments to enhance fluid and heat flow. Numerous studies have investigated the enhancement of heat transfer in L-formed vented cavities by inserting heat-generating components, filling the cavity with nanofluids, providing an inner rotating cylinder and a phase-change packed system, etc. Contemporary work has examined the thermal performance of L-shaped porous vented enclosures, which can be augmented by using metal foam, using nanofluids as a saturated fluid, and increasing the wall surface area by corrugating the cavity’s heating wall. These features are not discussed in published articles, and their exploration can be considered a novelty point in this work. In this study, a vented cavity was occupied by a copper metal foam with PPI=10 and saturated with a copper–water nanofluid. The cavity walls were well insulated except for the left wall, which was kept at a hot isothermal temperature and was either non-corrugated or corrugated with rectangular waves. The Darcy–Brinkman–Forchheimer model and local thermal non-equilibrium models were adopted in momentum and energy-governing equations and solved numerically by utilizing commercial software. The influences of various effective parameters, including the Reynolds number (20≤Re≤1000), the nanoparticle volume fraction (0%≤φ≤20%), the inflow and outflow vent aspect ratios (0.1≤D/H≤0.4), the rectangular wave corrugation number (N=5 and N=10), and the corrugation dimension ratio (CR=1 and CR=0.5) were determined. The results indicate that the flow field and heat transfer were affected mainly by variations in Re, D/H, and φ for a non-corrugated left wall; they were additionally influenced by N and CR when the wall was corrugated. The fluid- and solid-phase temperatures of the metal foam increased with an increase in Re and D/H. The fluid-phase Nusselt number near the hot left sidewall increased with an increase in φ by 25–60%, while the solid-phase Nusselt number decreased by 10–30%, and these numbers rose by around 3.5 times when the Reynolds number increased from 20 to 1000. For the corrugated hot wall, the Nusselt numbers of the two metal foam phases increased with an increase in Re and decreased with an increase in D/H, CR, or N by 10%, 19%, and 37%. The original aspect of this study is its use of a thermal, non-equilibrium, nanofluid-saturated metal foam in a corrugated L-shaped vented cavity. We aimed to investigate the thermal performance of this system in order to reinforce the viability of applying this material in thermal engineering systems.

The Fukushima nuclear catastrophe in 2011 had a significant effect on nuclear development worldwide. Despite the numerous studies that assessed nuclear acceptance in recent times, there is currently no study that provides a detailed bibliometric review on the available literature. Therefore, a bibliometric review of public acceptance and nuclear energy has been carried out to better understand their evolution, trends, and future research potentials. In the period under review (2000–2023), 263 documents were published, and a total of 659 researchers produced the literature with an annual growth rate of 7.9%. The factorial analysis revealed key themes; grouped into three clusters: technical operational aspects of nuclear energy (Cluster 1), safety and risk management (Cluster 2), and public policy and social issues (Cluster 3). The word cloud analysis identified common subjects of research such as nuclear safety, risk perception, and public trust, suggesting that further research is needed on societal concerns and effective communication strategies. Collaboration patterns revealed strong research linkages between China and the US, and a number of other internationally collaborative countries such as the UK, Germany, and Japan. Future studies should investigate prediction models for public perceptions of nuclear power and concentrate on comprehending the elements that affect public trust, especially in developing nations. Research on public-private partnerships, psychological aspects influencing attitudes, and the effectiveness of educational initiatives is also crucial. The policy recommendations highlights the need for open governance and broad public participation in decisions concerning nuclear energy to alleviate concerns on safety and environmental risks and therefore nurture public trust in nuclear power.

To overcome the weak thermal conduction of the phase change materials (PCM), This investigation aims to study the effect of circular Y-shaped fins added to a two-pipe latent heat-saving unit compared with conventional circular fins. The system is placed in a straight-up orientation, and the PCM is located in the annulus, whereas hot water is moved inside the internal tube to charge the phase change material (PCM) with a phase change point of 35°C. Different independent geometric factors of the fins involving the length of the stem and angle of the tributaries to the horizontal line and the number of Y-shaped fins are analysed. The impact of the working fluid's Reynolds number and temperature (as the input parameters) are evaluated as a sensitivity analysis to control the output (melting time and rate). The results show that increasing the height and number of the fins and reducing the angles of the tributaries results in higher performance of the system. For the optimal case, increasing the Reynolds number of the working fluid from 500 to 2000 results in 31% reductions in the melting time. Moreover, raising the working fluid's temperature from 45° to 55° reduces the melting time by ∼44%.

This paper examines the impact of various parameters, including frames, zigzag number, and enclosure shape, on the solidification process and thermal energy storage rate of a vertical phase change material (PCM) container. The study also assesses the effects of the flow rate of the heat transfer fluid as well as changing the materials of the PCM between RT35 and RT35HC. In addition, the study compares the framed versus unframed systems and, subsequently, the best case was tested with various zigzag pitch numbers before changing the zigzag-shaped structure to arc and reversed-arc. The findings are examined by contrasting the different scenarios’ liquid fractions, temperature distributions, solidification rates, and heat storage rates. The results show that the framed geometry is 66% faster to reach the target temperature compared with the unframed geometry and employing a zigzag enclosure in a PCM can significantly improve the solidification time and heat recovery rate. As the number of pitches in the zigzag enclosure increases, the improvement rate decreases but still improves the solidification time and heat recovery rate. The reversed-arc-shaped structure has the best performance compared with the other undulated surfaces. For the system with RT35HC, the discharge time is 55% higher compared with that of the system with RT35, while the discharge rate is 8.2% higher for the former during the first 3000 s of the discharging process. Graphical Abstract Graphical Abstract

In this study, the effect of fin number and size on the solidification output of a double‐tube container filled with phase change material (PCM) was analyzed numerically. By altering the fins' dimensions, the PCM's heat transfer performance is examined and compared to finless scenarios. To attain optimal performance, multiple inline configurations are explored. In addition, the initial conditions of the heat transfer fluid (HTF), including temperature and Reynolds number, are considered in the analysis. The research results show a significant impact of longer fins with higher numbers on improving the solidification rate of PCM. The solidification rate increases by 67%, 170%, 308%, and 370% for cases with 4, 9, 15, and 19 fins, respectively, all with the same fin length and initial HTF boundary condition. The best case results in a solidification time that is 4.45 times shorter compared to other fin number and dimension scenarios. The study also found that moving from Reynolds numbers 500 to 1000 and 2000 reduced discharging times by 12.9% and 22%, respectively, and increased heat recovery rates by 14.4% and 27.9%. When the HTF entrance temperature was 10°C and 15°C, the coolant temperature showed that the entire discharging time decreased by 37.5% and 23.1% relative to the solidification time when the initial temperature was 20°C. Generally, this work highlights that increasing the length and number of fins enhances thermal efficiency and the phase change process. This research investigates the impact of the number and size of circular fins on the solidification output of a double‐tube container using phase change material. By optimizing the arrangement of the fins using 19 circular fins, the discharge rate improves by 370% compared with the no‐fin heat exchanger change from 38 to 10.2 W.

This research explores the feasibility of using a nanocomposite from multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) for thermal engineering applications. The hybrid nanocomposites were suspended in water at various volumetric concentrations. Their heat transfer and pressure drop characteristics were analyzed using computational fluid dynamics and artificial neural network models. The study examined flow regimes with Reynolds numbers between 5000 and 17,000, inlet fluid temperatures ranging from 293.15 to 333.15 K, and concentrations from 0.01 to 0.2% by volume. The numerical results were validated against empirical correlations for heat transfer coefficient and pressure drop, showing an acceptable average error. The findings revealed that the heat transfer coefficient and pressure drop increased significantly with higher inlet temperatures and concentrations, achieving approximately 45.22% and 452.90%, respectively. These results suggested that MWCNTs-GNPs nanocomposites hold promise for enhancing the performance of thermal systems, offering a potential pathway for developing and optimizing advanced thermal engineering solutions.

The thermal management of cylindrical battery packs, widely used in electric vehicles and energy storage systems, is a critical aspect of ensuring their safety, performance, and longevity. As energy densities increase, effective cooling solutions become essential to address the challenges posed by excessive heat generation and uneven temperature distribution. This review has highlighted the promising potential of hybrid nanofluids and phase change materials (PCMs) in advancing thermal management systems for battery packs. Hybrid nanofluids, offering enhanced heat transfer properties, and PCMs, capable of storing and dissipating latent heat, represent a promising synergy for improving thermal management systems. This review provides a comprehensive analysis of the role of hybrid nanofluids and PCM in addressing the thermal challenges of cylindrical battery packs. The paper discusses heat generation mechanisms, the drawbacks of existing cooling methods, and the advantages of integrating these advanced materials into thermal management systems. By identifying research gaps and opportunities, this review offers a pathway for optimizing battery performance and highlights future research directions necessary for scalable and sustainable solutions. According to this review, future research should concentrate on creating hybrid cooling systems that effectively combine active, passive, and hybrid cooling techniques. Additional advancements in computer modeling, nanotechnology, and material science will be crucial to achieving the full potential of these innovative materials and overcoming existing limitations.

This study examined the sustainability of utilizing a hybrid energy system to supply electricity to households in the Nasiriyah Mesopotamian Marshes. The urbanization rate in Iraq stands at 70%, and the energy sector predominantly relies on fossil fuels. This dependency puts the country in an energy crisis, necessitating a shift toward green and renewable energy sources. This study addresses this issue by analyzing the feasibility of a renewable energy-based hybrid power production system in the Nasiriyah Mesopotamian Marshes. Utilizing HOMER PRO software for simulation, the system was designed to operate in six different system designs, with four hybrid configurations incorporating solar, wind, and diesel generators. The conducted techno-economic analysis helped to achieve three main objectives: minimizing the net present cost, levelizing energy cost, and reducing the negative environmental impacts of using fossil fuels. The best selection from the designed systems was a hybrid system comprising only wind and solar operating for all seasons, which was considered the most suitable one for the Nasiriyah Mesopotamian Marshes, resulting in the lowest NPC of $2.2 million and LCOE of 0.157 $/kWh. This hybrid system outperformed the other five variations in operation, maintenance, and reliability. Consequently, an off-grid hybrid system emerges as a robust alternative and a green policy initiative, ensuring a smooth energy flow in the Mesopotamian Marshes.

1D and 2D carbon nanomaterials such as multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) were investigated numerically. The thermophysical properties of water and nanofluids using MWCNTs in different outer diameters (ODs) and GNPs in different surface areas (SSA) were measured at an inlet temperature of 303.15 K and 0.1wt.%. The 3D geometry was solved under a fully developed turbulent flow of 6000 ≤ Re ≤ 16,000 using the model of k-ω SST via (ANSYS FLUENT 2022R2) software. Four numerical networks, Polyhedra, Polyhexacore, Hexacore, and Tetrahedral, were optimized. Moreover, seven parameters were discussed, namely wall surface temperature (T w ), heat transfer coefficient (h tc ), average Nusselt number (Nu avg ), friction factor (f), pressure drop (ΔP), and total thermal performance index (PI th ). Polyhexacore was the main grid over Polyhedra, Hexacore, and Tetrahedral with the average error (Dittus-Boelter: 2.754%, Gnielinski: 2.343%, Blasius: 1.441%, and Petukhov: 0.640%). Heat transfer increased by 18.38% with GNPs-300, 22.05% with GNPs-500, 23.25% with GNPs-750, 13.63% with CNT < 8 nm, and 11.42% with CNT 20-30 nm, relative to H 2 O at Re = 16,000. Pressure drop increased by about 42.01% with GNPs-300, 45.16% with GNPs-500, 44.84% with GNPs-750, 36.72% with CNT < 8 nm, and 34.39% with CNT 20-30 nm.