Journal of Thermal Analysis and Calorimetry最新文献

Electric vehicles have been considered as a viable solution to combat the major global issues of increasing energy demands and environmental pollution, and hence are being promoted unceasingly across the world. Several fiscal and non-fiscal policy measures have been proposed and implemented by the Governments to enhance the market share of electric vehicles (EV) significantly. However, their efficacy is subjected to various control parametric scenarios. In India, the EV market is still in its initial stage and has significant acceleration potential. The present work investigates the effectiveness of various state-level promotional schemes in India empirically, using static regression panel data modeling methods. Based on the econometric analysis, the fiscal incentive policy in terms of favorable purchase subsidies and scrapping incentives is reported to be more influential on the consumer side in promoting EV diffusion to the Indian market. Effective charging infrastructure development is also an important aspect to have supportive space in Government monetary support policies. However, policies regarding favorable energy tariff have not been proved so effective at this stage; hence, it is recommended to get reviewed. Further, out of several control factors, literacy rate is observed to be the most influencing factor for significant shift of potential consumer toward adoption of electric vehicles over corresponding conventional alternatives.

There is an increasing need for sustainable solar thermal energy systems for power production, desalination, cooling and heating, and even cooking in the current world. The most significant challenge for the further development of solar-based technology is the discontinuity and lack of solar irradiance, especially on cloudy days and night hours. Thermal energy storage is the most suggested technology to tackle this challenge partly or mostly. Phase change materials can have a notable role as thermal energy storage in solar thermal energy systems. Besides, parabolic dish collectors are a type of solar collector technology that can be utilized in various thermal systems due to their high concentration ratio and working temperatures. Hence, in this review, the applications of phase change materials in various solar parabolic dish collectors will be investigated in detail. Moreover, the research works are divided into five main categories: power production systems, cooling-heating systems, desalination systems, solar cooker systems, and multigeneration systems. Based on the literature, studies of phase change material's applications in dish collectors are currently limited to theoretical studies in several cases. There is vast research need for further experimental investigations in all the mentioned categories. To this end, some concluding points and suggestions for future studies will be presented to the researchers.

Aiming at the demand for improving the heat release performance of solid propellants for high energy and complex practical application scenarios, the B–Mg–Al ternary alloy is proposed as a metal fuel additive. Based on the unique phase distribution of B–Mg–Al ternary metal alloy and the existing theory of ignition and combustion of metal particles, the kinetic simulation of ignition and combustion of B–Mg–Al ternary metal alloy particles in complex alternating atmosphere is carried out by combining with the virtual alternating atmosphere environment. The model calculates the combustion time t_c of 10 μm B–Mg–Al alloy particles in H₂O(g), H₂O(g)/Air alternating mode, and Air to be 3.50 ms, 3.98 ms, and 4.60 ms, respectively, and the comparative errors with the experimental measurement of combustion time are kept around 5%, which verifies the reliability of the model results. The simulation study shows that the order of thermal oxidation reaction and the order of combustion of the monomolecular group elements of B–Mg–Al ternary alloy particles are Mg, Al, and B, which to some extent indicates that the addition of Mg and Al has the potential to improve the ignition and combustion performance of B. In addition, there are obvious differences in the ignition and combustion performance and heat transfer performance of the alloy particles under H₂O(g) and that of Air with the same concentration, which leads to significant instability in both ignition and combustion processes at variable medium.

Due to the versality, surface imperfections and diverse redox chemistry of Cu_xS, hybrid ion exchangers (HIXs) containing these particles are an interesting object of research, including thermal transformation. The composite materials used for testing were strongly basic anion exchangers, with macroreticular (M) and gel-type structure (G), containing in the poly (styrene/divinylbenzene) skeleton fine particles of covellite/brochantite (M1), covellite (M2), covellite/digenite/djurleite (G1) and covellite/digenite (G2). The prepared HIXs contained 12–16 mass% S + Cu. They were subjected to thermal analysis under air and N₂ to identify the role of the inorganic phase in decomposition of the polymeric phase. The results were discussed on the basis of the TG/DTG curves and X-ray diffraction (XRD) patterns of the solid residues (CuO after combustion, carbon/Cu₂S after pyrolysis). It was found that Cu_xS in the resin phase exhibited oxidative activity promoting the combustion process. The polymeric skeleton of HIXs decomposed in air at a much lower temperature compared to pure resins (400 vs 600 °C). The TG/DTG curves had a model shape, three separate conversions occurring in a narrow temperature range, which indicated sequential decomposition. The low consumption of hydrogen for the reduction of Cu_xS to Cu₂S during pyrolysis was not conducive to condensation of alkyl radicals and increase of the mass of carbon matter. The results advance the understanding of the effect of copper/sulfur-containing fine particles on the thermal decomposition of anion exchanger and can be useful in preparation of multifunctional carbon-containing composite materials.

This study investigates the effects of microwave radiation on the fracture characteristics and thermal damage mechanisms of shale. Microwave heating response tests were conducted on Shuigoukou Formation shale to examine its heating characteristics under varying microwave irradiation durations. Fracture toughness tests were performed to assess the impact of different bedding angles on shale fracture toughness and to elucidate the failure modes of shale at various bedding orientations. Results reveal that shale fracture toughness exhibits temperature thresholds under microwave action, which vary with bedding angle. For crack-splitter, crack-arrester, and crack-divider type shales, the temperature thresholds were determined to be 50 °C, 125 °C, and 200 °C, respectively. The fracture toughness decreases sequentially from crack-divider to crack-arrester to crack-splitter type shales, with all types showing a reduction as microwave radiation time increases. The thermal damage observed in shale under microwave heating correlates with the wave-absorbing characteristics of its various components. Moisture content, dielectric constant, and mineral composition were identified as the primary factors influencing the microwave thermal effect on shale. The findings contribute to a deeper understanding of the structural damage characteristics and fracturing mechanisms of shale reservoirs during thermal stimulation.

With energy resources being fossil fuel-based, increasing energy production has already reached levels that threaten human health. In this situation, the use of alternative energy sources is seen as the only solution. Solar energy is seen as the most promising source among these alternative energies in terms of its potential. Hence, therefore, this study focuses entirely on one of the solar energy sources. This research aims to assess the impact of the design and underground additional heat source (AHS) on the system performance based on the Manzanares pilot plant (MPP), the first on-site practice of solar chimney power plants. Divergent chimney-SCPP with sloping collector (DISCPP) is analysed in the present work. For DISCPP, the influence of the underground AHS in the range of 50–250 °C on the system outputs is examined. The study demonstrates a remarkable enhancement in power output (PO), with the plant generating 51,545 kW under the reference case conditions. The findings signify that when utilising the DISCPP system, the output soars to 247,672 kW under identical climatic conditions. During sunless hours, a PO of 61,956 kW is achieved with the DISCPP at an underground AHS temperature of 50 °C. Moreover, when the source temperature reaches 250 °C during sunless hours, the DISCPP system continues to deliver a significant output of 450 kW. These outcomes underscore the exceptional performance and reliability of the DISCPP system, even under varying conditions.

Electronic components cooling (ECC) for manufacturing and technological uses has become one of the most interesting topics that researchers have focused in the modern era. Because of the continuous minimization in the electronic components size and substantial quantity of heat generation; the traditional cooling methods cannot be able to follow rapidly reduction in such high amount of heat flux. The use of nanofluid is an intriguing possibility for ECC. Such advancements may result in advancements in the field of electronic equipment in addition to improved efficiency of energy. The present article proposes is to study the use of various types of nanofluids over different shapes for preventing redundant heat, to effectively control the thermal stress as well as to maintain the electronic components temperature. Some fascinating features related to utilizing nanofluids to ECC are also addressed. In addition, further study prospects and directions in this area are put forward. It can be noticed that the addition of γ-Al₂O₃ NPs in water increases the heat transmission efficiency by 37% and 28%, while keeping Reynolds numbers (Re = 601.3 and 210) respectively. The cooling ability of the automobile radiator upsurges up to 17.46% with the addition of Al₂O₃-NPs.

The present work explores a novel water-ethylene glycol-based ternary hybrid nanofluid, comprising aluminium oxide (Al₂O₃), zinc oxide (ZnO), and reduced graphene oxide (rGO) for electric vehicle traction system radiator coolant. A multi-objective hybrid optimisation technique is used to determine the optimal composition of nanofluid and operating conditions of the radiator. Design of experiments based on response surface methodology is used to develop regression models for performance parameters such as Peclet number, normalised Nusselt number, Bejan number, and second law efficiency. Further, optimised operating conditions and composition of nanofluid were derived using invasive weed optimisation (IWO) algorithm for the best performance of radiator. A multiphase numerical analysis is performed using Ansys® Fluent’s k-ɛ turbulence model to evaluate the performance parameters. Additionally, an experimental study is conducted to understand the degree of consensus with the developed numerical model. Based on optimisation, a ternary hybrid nanofluid concentration of 1.91% with 3.33: 3.94: 3.65 proportion of Al₂O₃: ZnO: rGO is identified to be significant at coolant and air inlet conditions of 98.61 °C & 13.96 LPM and 33.27 °C & 1108.6 CFM, respectively. The optimised performance metrics achieved through IWO indicate a Peclet number of 3511, normalised Nusselt number of 1.85 with Bejan number of 0.82 and a second law efficiency of 0.73.

This paper investigates the effect of porous fin parameters on natural convection heat transfer performance in a closed cavity under sinusoidal periodic temperature boundary conditions. The study examines the impact of periodic boundary parameter variation on the Nusselt number, which represents the ratio of convective heat transfer to conduction heat transfer close to the wall region. The study results indicate that the average Nu number on the heat source surface fluctuates with different sinusoidal patterns, and the top surface of the heat source has a greater impact on convective heat transfer in the cavity. The analysis of the response surface method reveals that the interaction between the fin height S_a and the fin length L_a has the most significant influence on the average Nu of the heat source surface. The optimal combination of fin parameters coming from the response surface method is: S_a (0.35 ≤ S_a ≤ 0.65), L_a (0.06 ≤ L_a ≤ 0.3), ΔS_ab (0.05 ≤ ΔS_ab ≤ 0.25), A(0.5 ≤ A ≤ 1), B (0.004 ≤ B ≤ 0.016), θ (30° ≤ θ ≤ 150°). Under the combination of these parameters, the time-average Nu number on surface of heat source reaches the maximum value 11.63, which is 13.00% higher than that without fins. The convective heat transfer intensity in the cavity increases with the increasing dimensionless amplitude a. In addition, the time-averaged Nu number on the surface of the heat source has a negative correlation with the dimensionless period τ_p.

Because of environmental concerns, HFCs that were once widely used in air-conditioning and refrigeration systems may soon be phased out. The main reason for the phase-out of HFCs is that of their high potential for global warming (GWP). Consequently, there is now a greater need for appropriate, greener alternatives. In the recent years, significant initiatives are taken toward hydrocarbon (HC) refrigerants or other eco-friendly refrigerants to ensure the sustainability of the environment. In this research work, an experimental examination has been made using green hydrocarbon refrigerants, i.e., a mixture of R600a and R290 in a ratio 55:45, as a substitute to R134a in a 150 L domestic refrigerator. Continuous running experiments have been conducted at various ambient temperatures (24, 29, 34, 39, and 43 degrees Celsius), whereas cycling running (ON/OFF) experiments were piloted solely at 29 degrees Celsius. The results revealed that hydrocarbon combination has lowered the energy consumption by 13.8% with 2.85–4.6% increase in COP. Compared to R134a discharge temperature, the exit temperature of green mixture hydrocarbons is found to be 6–14 K lower. Overall, the aforementioned hydrocarbon refrigerant mixture has proven to be the greatest long-term solution for phasing out R134a.