Journal of Thermal Analysis and Calorimetry最新文献

The increasing demand for hydrogen as an energy carrier requires the development of efficient and sustainable production strategies. Methane reforming is a widely used method for hydrogen production, and catalysts play a crucial role in optimizing this process. This paper provides a comprehensive review of the catalytic aspects of methane reforming, highlighting significant progress and recent advancements. After reviewing various research works, it was seen that the conversion of methane and carbon dioxide is influenced by the specific surface area of catalysts. It is observed that the catalysts with larger surface areas exhibit higher methane conversion rates, although exceptions are observed in the case of perovskites, which demonstrate good conversion efficiency despite their smaller size. Cobalt (Co) and nickel (Ni) are commonly employed in catalysts for achieving higher conversion rates. Other than that, various rare-earth catalysts were also evaluated in the paper. To further optimize the production strategy, several crucial points are identified. These include a comprehensive understanding of the reaction mechanisms for catalyst design, the integration of in situ characterization techniques for studying catalyst changes and active species, collaboration between theoretical calculations and experimental studies, and the development of highly efficient and stable catalysts. Emphasis is placed on exploring cost-effective options, such as nickel and other non-noble metal catalysts, while assessing their performance at low temperatures and in advanced reforming systems. With the increasing importance of hydrogen and syngas production, upgraded reforming systems are expected to flourish soon.

Nanoparticle coatings present a highly effective method for significantly enhancing the performance of solar distillers by improving heat transfer, evaporation, and condensation processes. This review provides a comprehensive examination of the current research on nanoparticle-coated solar stills, highlighting how nanoparticles improve thermal conductivity, absorb solar energy more efficiently, and promote dropwise condensation to increase freshwater productivity. Various nanoparticles, including metal oxides and carbon-based materials, have been studied for their ability to optimize solar still performance. However, challenges such as nanoparticle stability, cost, and environmental impact remain. This paper consolidates research efforts, analyses key findings, and outlines future directions for advancing the application of nanoparticle coatings in sustainable water purification technologies.

In this study, thermophysical properties of MWCNT (15%)-ZnO (85%)/ethylene glycol hybrid nanofluid (HNF) have been investigated statistically and experimentally. Understanding thermal behavior of nanofluid (NF) in different laboratory conditions and also determining the correlation between process factors and how the factors affect the thermal behavior are the most important objectives of this study. This study is performed under laboratory conditions (T = 28–55 °C, SVF = 0.05–1.85%). Experimental results show with increasing SVF and temperature; thermal conductivity (TC) of NF increases due to increasing collisions number, increasing kinetic energy and increasing energy transfer between fluid layers. The Maximum increase and minimum increase in TC occur in laboratory conditions of SVF_max = 1.85% and SVF_min = 0.055 % which was equal to 27% and 2.5%, respectively. To predict and determine the correlation between process variables, RSM is used with a second-order model with R-squared = 0.9854 and − 1.5% < MOD <  + 1.5%. Also, the price performance factor (PPF) has been studied for two different HNFs.

This study delves into the computational exploration of the impact of magnetic intensity, magnetic nanofluid, flow rates and heat transfer coefficient in the form of Nusselt number on inclined ribbed channels with both parallel and staggered configurations for the cooling of sodium-ion and lithium-ion batteries in electric vehicles. Employing Fe₃O₄ + H₂O as the working fluid, within a minichannel with multiple magnets at different locations, namely 15 mm, 25 mm and 15 mm and 25 mm, the parallel and staggered inclined ribbed channel Nusselt number (Nu) increased with magnetic field intensity, reaching maximum of 152.81% for staggered ribbed minichannel configuration at 2000 Gauss (G). Similarly, the skin friction experienced an increment with magnetic field intensity for staggered ribbed minichannel configuration and for parallel ribbed minichannel when both the magnets were placed at the location of 15 mm and 25 mm from the inlet but decreased with increasing Reynolds number. Notably, the thermal enhancement factor (TEF) consistently surpassed greater than unity for all investigated cases. These findings carry significant implications, particularly in EV cooling, offering valuable insights for developing more efficient and tailored cooling solutions for advanced EV battery thermal management.

This research aims to assess the significance of nanoparticle size on the natural convection magnetohydrodynamic (MHD) boundary layer flow of a dusty nanofluid across a stretching sheet. Dusty fluids are widely used in industries such as manufacturing and construction, particularly in areas like infrastructure development and material processing. They are used in petroleum transportation, gas purification, power plant piping, automotive exhaust systems, and sedimentation operations. In this study, dusty nanofluid is composed of copper nanoparticles suspended in a mixture of C(_2)H(_6)O(_2)-H(_2)O (50–50%) with a Prandtl number (hbox {Pr}=3.97). The similarity transformations convert the governing partial differential equations (PDEs) into ordinary differential equations (ODEs). These ODEs are then solved numerically using MATLAB’s built-in "bvp4c" method. The effects of various involved parameters on velocity, temperature, skin friction, and Nusselt number are exemplified graphically. The findings indicate that increasing the nanoparticle radius causes temperatures to decrease for both phases, while increasing velocities for both phases. A rise in the suction parameter results in lower temperature and velocity for both phases. A surge in the Biot number significantly raises the temperatures of both phases. Increasing the suction parameter, nanoparticle radius, and Biot number increases the Nusselt number, which optimizes effective heat transfer efficiency by improving thermal conductivity and nanofluid mobility. Skin friction increases for smaller nanoparticles and enhanced suction.

An advanced numerical investigation was conducted on a tubular heat exchanger utilizing CuO-water nanofluid between 0.01% and 0.04% volume fraction to elucidate enhancements in heat transfer rate and effectiveness. The study incorporated twisted tape inserts with three distinct sweeps (5, 10, and 15) for fully developed turbulent flow conditions. The analysis explored varying mass flow rates of the hot nanofluid (0.2–0.5 kg s^-1), while maintaining a constant cold fluid mass flow rate of 0.2 kg s^-1. The k-ε turbulence model was employed to accurately predict heat transfer characteristics in the turbulent regime. Swirl flow analysis revealed a bifurcation of flow patterns: one proximal to the wall and another distal. Results demonstrated a linear correlation between mass flow rate and both heat transfer rate and effectiveness. Peak performance was observed at the highest flow rate, with the maximum effectiveness reaching 0.37 and the heat transfer coefficient attaining 2511 W m^-2 K^-1. This study provides valuable insights into the thermal performance optimization of tubular heat exchangers using nanofluid and twisted tape inserts, offering potential for significant efficiency improvements in heat transfer applications.

In the current research, a quasi-two-dimensional numerical model is used for energetic and exergetic performance predictions taking into account eight inline PTC modules with variable geometries along with the main flow direction, for Therminol VP-1 and Syltherm 800 heat transfer fluids. There are a total of thirty-seven input variables, being thirty-two regarding the geometrical parameters and five environmental/operating parameters. Surrogate-based optimization procedures (Kriging metamodel combined with Non-Dominated Sorting Genetic Algorithm, NSGA-II) are used to build the Pareto frontier for two objective functions: (i) maximization of both useful gain and thermal efficiency and (ii) maximization of useful gain and minimization of exergy destruction. The optimization results indicated that the useful gain of 8 inline PTC array can reach up to 1.0 MW for both thermal oils. By variation in the input parameters along with the PTC array, a broad range useful gain can be achieved, with negligible thermal efficiency degradation. With regard to the Pareto frontier of useful gain and exergy destruction, there is an important asymptotic point for useful gain, in which its augmentation just promotes the increase in exergy destruction. In terms of concentration ratio, the Pareto fronts showed that about 95% and 90% of PTC modules can be assumed at “heterogeneous” along with the array for the first and second objective functions, respectively. At last, convective heat transfer coefficient and outer receiver and outer glass cover temperatures along with the PTC array for different individuals of the Pareto fronts are discussed in detail.

Graphical abstract

The vaporization enthalpies at T = 298.15 K and vapor pressures from T = (298.15 − 450) K of the major hydrocarbon components in chamomile and cypriol are evaluated by correlation gas chromatography. The components in chamomile include the following four substances: (E, E) α-farnesene, E β-farnesene, bicyclogermacrene and germacrene-D. In cypriol, similar properties have been evaluated for cyperene, α-copaene, and rotundene. Both chamomile and cypriol have been used in the practice of traditional medicine.

This work aims to study the use of polyamide 12 in oil pipelines to replace steel, which is more susceptible to corrosion. Pipes of polyamide were installed in oil fields and, after 1 year of operation, were removed and analyzes. The outer layers of all field samples and the unaged sample did not show, in the DSC, any primary peak close to the melting peak. This is due to the extrusion and the formation of different crystalline structures on the inner surface, giving rise to two melting peaks. All layers of the field samples showed endothermic peaks, but the unaged sample did not. This can be attributed to the annealing process, but this phenomenon does not affect the properties PA12. The results showed no degradation and PA12 can be a viable alternative for oil pipelines, providing savings of more than 50% compared to steel, in addition to operational, human and environmental safety.

Development with the expansion of electronic devices, increased electricity consumption, and supplying the required power are some challenges involving different countries. Iran is also currently consuming in its industries that to supply electricity, it is necessary to adjust the program of various blackouts, hence the stoppage of the production of industries and mines has caused significant damage. This paper presents a comprehensive feasibility study for the construction of a 10-MW grid-connected photovoltaic (PV) power plant aimed at mitigating energy deficits in Iran's iron ore mining sector, particularly during blackout periods. Utilizing HOMER software for technical simulation, the proposed solar plant is projected to generate approximately 16 million kWh annually, with 2 million kWh available during shutdowns. Financial analysis conducted through CAMFAR software indicates a payback period of 8.6 years, an internal rate of return (IRR) of 12.67%, and a net present value of $3.45 million, underscoring the project's economic viability. The plant’s capacity to compensate for the production of 66,750 tons of iron concentrate during outages underscores its potential for significant financial benefits.