Search Results (223)

The sustainable development of the ceramics industry is severely impeded by its intensive energy consumption and the concomitant deficits in cooling and freshwater resources. To address these bottlenecks, this study proposes an integrated ejector refrigeration (ER)–humidification–dehumidification (HDH) hybrid system, harnessing ceramic waste heat as the driving energy source to improve overall energy efficiency. A thermodynamic model was developed to analyze the heat transfer characteristics of the ER-HDH system. Comprehensive investigation focuses on the influences of key operating parameters on refrigeration performance, desalination output and overall system efficiency. The results demonstrate that the proposed ER–HDH hybrid system facilitates the efficient thermodynamic cascading of waste heat from both flue gas and internal thermodynamic processes, achieving a high energy utilization factor (EUF) of 0.64 and an exergy efficiency η_Ex of 15.7%. The freshwater yield significantly outperforms that of a standalone HDH system, with the gain output ratio (GOR) more than tripling. The system performance is optimized under elevated generator and evaporator temperatures (T_g and T_e), coupled with a reduced condenser temperature T_c. Across their respective tested ranges, the EUF increases by averages of 19.1%, 45.1% and 38.9%. Furthermore, raising the feed seawater temperature T_{sw_in} significantly elevates the moist air humidity ratio, which in turn drives substantial enhancements in GOR and EUF, by over 83.2% and 58.1%, respectively. T_e and T_{sw_in} should be prioritized to enhance refrigeration and freshwater productions, respectively, while T_c serves as the key determinant for maximizing η_Ex. This study introduces an open dual-cascade ER-HDH system for mid/low-grade flue gas utilization and elucidates the distinct thermodynamic mechanisms governing subsystem interactions, and it addresses a critical knowledge gap in prevalent closed-loop solar-driven ER-HDH systems. Full article

The convective drying of agricultural materials is an energy-intensive process, and optimizing dryer design is critical for improving efficiency and product quality. This study presents a comprehensive heat and mass transfer model for the convective drying of alfalfa leaves in a rotary drum dryer. Freshly harvested leaves with an initial moisture content of approximately 70% (w.b.) were used as the test material. The proposed system features a simplified drum design aimed at enhancing process efficiency while reducing equipment complexity. The primary objective was to reduce the moisture content of alfalfa leaves to below 50% to ensure their quality during subsequent storage and transportation. To determine the optimal operating conditions, the kinematics of leaf motion inside the rotating drum and the associated heat and mass transfer phenomena were investigated through analytical modeling, numerical simulation, and experimental studies on a laboratory-scale physical model. An analytical model was developed to establish relationships between transverse kinematic characteristics (detachment condition, Froude number, drum inclination angle), average longitudinal velocity, and residence time. Numerical simulations based on the Navier–Stokes equations (continuity, momentum, and energy) provided detailed moisture content distributions within individual leaves under varying airflow orientations and drying durations. The novelty of this work lies in the integrated determination of optimized operating parameters through combined analytical, numerical, and experimental approaches. A regression model relating final moisture content to key process variables (air velocity, temperature of 60 °C, drum rotation frequency and mass of loaded material) was developed from experimental data, yielding practical recommendations for the design and operation of rotary drum dryers for alfalfa and similar agricultural materials. Full article

Rice cooking is a time-consuming process, and conventional heating methods often suffer from low heating efficiency and non-uniform heat transfer, which may compromise cooking quality. Although pulsed ohmic heating (OH) has shown potential for accelerating food heating, its effects on the quality formation and structural evolution of cooked rice remain insufficiently understood. Therefore, this study applied OH technology to improve the cooking efficiency and quality of indica rice. Through single-factor and response surface methods, the optimal OH parameters were determined: 18 min treatment time, 9.4 μs pulse width, 0.52 kV/cm electric field strength, and 265 Hz frequency. Under these conditions, the cooking time was significantly reduced by 28% compared to traditional rice cookers, achieving a comprehensive quality score of 88.42 points. Optimized OH treatment improved water absorption and volume expansion ratio, reduced hardness, and enhanced the overall flavor characteristics, accompanied by changes in the microstructure and starch organization. Multi-scale structural analyses indicated that OH treatment was associated with accelerated starch gelatinization, reduced starch crystallinity, enhanced moisture migration, and possible alterations in starch–protein interactions, which were consistent with the observed improvements in rice texture. Importantly, at the 18 min maturation point, the estimated glycemic index of OH-treated rice showed no significant difference compared with traditionally cooked rice (83.69 vs. 82.88, p > 0.05), ensuring nutritional quality. These findings suggest that OH is a promising technology for improving rice cooking efficiency and quality while maintaining nutritional properties. Full article

Fluidic oscillators (FOs) are self-excited jet-generating devices without moving parts that convert steady fluid supply into oscillatory jets through inherent flow instabilities. Among various FO configurations, dual-feedback fluidic oscillators (DFFOs) have attracted extensive attention due to their simple structure, high reliability, stable oscillation characteristics, and broad applications in active flow control, heat transfer enhancement, and fluid mixing. However, conventional trial-and-error-based optimization methods are limited by strong parameter coupling and trade-offs among multiple performance objectives, such as oscillation frequency, jet deflection angle, and energy efficiency. This review systematically summarizes recent advances in performance enhancement strategies for DFFOs from the perspective of “from geometric control to intelligent design”. The effects of multi-scale geometric regulation, including macroscopic structures, internal microstructures, and manufacturing-related factors, are discussed. Advanced optimization approaches, including active control, novel configurations, inverse design, and data-driven methods, are further reviewed. Particular attention is given to additive manufacturing challenges and DFFO performance under multiphase flow conditions, including erosion, particle deposition, atomization, and mass transfer. Finally, future perspectives are proposed regarding multi-physical coupling, intelligent optimization, and engineering applications. This review provides a comprehensive reference for the cross-scale performance enhancement and intelligent design of DFFOs. Full article

This investigation meticulously examines the influence of activation energy, thermophoresis, Brownian motion, and magnetic fields on the flow dynamics and heat transfer characteristics of a non-Newtonian hybrid nanofluid comprising aluminum oxide (Al₂O₃), copper (II) oxide (CuO), and ethylene glycol over a horizontally stretching porous wedge. This research addresses the imperative need for enhancing energy transfer and thermal management systems, which possess considerable technical significance and industrial relevance. The flow equations were formulated into ordinary differential equations through the use of similarity transformations, which in turn were solved numerically by employing the spectral relaxation (SR) scheme. The findings indicate that the Brownian motion, activation energy, wedge angle, and magnetic field intensity are pivotal determinants of the system’s flow and thermal behavior. In particular, an increase in the wedge angle correlates with an augmentation of the Nusselt number while concurrently diminishing the thermal and diffusion profiles. A comparative analysis of the current investigation and earlier scrutiny revealed that hybrid nanofluids enhance mass and energy transfer rates in both studies. The novelty of this investigation is anchored in its comprehensive exploration of magneto-flow dynamics and the characteristics of hybrid nanofluids within the context of porous wedge-shaped geometries and external magnetic influences. The findings of this study extend previous research by offering quantitative elucidation regarding how pivotal parameters, such as wedge angles, activation energy, thermophoresis, and Brownian motion, affect heat and mass transfer phenomena, thus laying a robust groundwork for the optimization of hybrid nanofluid applications in engineering and industrial environments. The results are in robust agreement with the existing body of literature, thereby affirming the contributions of this study to the academic discourse in the field. Full article

With the increasing consumption of plant-based foods, allergies to these foods are becoming more widespread and seriously affect human health. This review focuses on the properties of major plant-based food allergens, including those from soybeans, peanuts, wheat, sesame, and tree nuts. The composition, stability, structure, and IgE-binding epitopes of allergens from these major plant allergenic foods are summarized. For peanuts, the major allergens include Ara h 1, Ara h 2, Ara h 3, and Ara h 6, with Ara h 2 and Ara h 6 being notably heat- and protease-resistant. Gly m 4, Gly m 5, and Gly m 6 are the predominant allergens in soybeans. The primary sesame allergens are Ses i 1, Ses i 2, Ses i 3, Ses i 6, and Ses i 7, with Ses i 1 serving as a stable and highly specific diagnostic marker. Wheat allergens are categorized by exposure route, with ingestion of allergens such as gliadins and glutenins being particularly relevant for food-induced reactions. Major storage proteins and lipid transfer proteins are central to the allergenicity of nut varieties (such as almonds, hazelnuts, and walnuts). Understanding these molecular characteristics is crucial for developing hypoallergenic food products using targeted processing methods. Further studies are needed to comprehensively investigate these allergenic characteristics. Full article

Boiling is one of the most effective mechanisms for heat transfer enhancement and is therefore widely applied in high-performance cooling systems for electronic devices, power electronics, and compact heat exchangers. A comprehensive understanding of the relationship between surface microstructure geometry and boiling dynamics enables the design of advanced surfaces with improved thermal performance and enhanced operational stability. This study presents an experimental investigation into the effect of inclined microchannel geometry on the pool boiling characteristics of FC-72 and ethanol, two working fluids with significantly different thermophysical properties. The experiments were conducted on copper surfaces with parallel microchannels of various widths, depths, and inclination angles, with the obtained results compared with those for a technically smooth reference surface. The experiments were performed under atmospheric pressure conditions with a gradually increasing heat flux. Boiling curves, heat transfer coefficients (HTCs), and critical heat flux (CHF) values were determined. The results demonstrate that properly designed microchannel geometries can significantly enhance boiling heat transfer by increasing the number of active nucleation sites and modifying the conditions of vapor bubble growth and departure. The most favorable thermal performance was achieved for surfaces with the smallest channel width, confirming the important role of microstructure geometry in governing boiling heat transfer mechanisms. For FC-72, the HTC increased by more than 200% compared with the reference surface, whereas ethanol exhibited higher HTC values and a more stable nucleate boiling regime over the entire investigated heat flux range. The results confirm that optimization of inclined microchannel geometry provides an effective strategy for designing surfaces dedicated to enhanced boiling cooling, while the effectiveness of surface modification depends on both microstructure characteristics and the thermophysical properties of the working fluid. Full article

Vacuum induction melting (VIM) of recycled powder with bulk master alloy represents an industrialized approach for recycling metallic waste. However, the intrinsic mechanisms governing the co-melting behavior of materials with distinct melting characteristics, such as powder bed and bulk alloy, remain insufficiently understood. To address this, a coupled multiphysics model was developed to simulate the evolution of induction melting involving homogeneous alloys with different morphologies. This model integrates magnetic, electric, and phase-field dynamics while incorporating melt convective heat transfer, thereby establishing a fully coupled electromagnetic-thermo-hydrodynamic framework. Through this modeling approach, the entire VIM process of melting homogeneous alloy with different morphologies can be comprehensively analyzed. The validity of the model was verified via small-scale VIM experiments using FGH96 powder/bulk composite, supported by infrared temperature measurements. This simulation methodology is not only applicable to small-scale recycling but can also be extended to large-scale industrial production, providing a reliable theoretical foundation for the recycling of powder materials. Full article

To satisfy the electricity demands and further improve the cooling performance of scramjets, the supercritical CO₂ Brayton cycle is adopted as a promising cooling and power supplying scheme. However, with the extremely high heat flux level of MW/m², a cooling channel featuring a rectangular cross-section with non-uniform heat flow and different positions of the heated wall relative to the direction of gravity make the flow and heat transfer characteristics of supercritical CO₂ within scramjet cooling channel extremely complex. In this study, the effects of different angles of the heated wall normal direction relative to the direction of gravity (θ) on the flow and heat transfer behavior of supercritical CO₂ within a scramjet cooling channel are comprehensively investigated. The results show that the spanwise heat transfer coefficient on the heated wall decreases while on the opposite wall it increases as θ increases. Moreover, the overall heat transfer performance is insensitive to variations in θ, but the heat transfer characteristics on different walls are sensitive to variations in θ. Moreover, the cases with lower θ provide better heat transfer performance for the heated wall, which is more significant for scramjet cooling due to having the highest heat load. In detail, the averaged HTC on the HW of θ = 180 deg for G = 900 kg/(m²s) is reduced by 11.79% in comparison to that of θ = 0 deg, while it is enhanced by 18.70%, 6.39% and 6.39% for the OW, LW and RW, respectively. Full article

Current research on the energy performance of tilted façades is largely confined to specific climatic contexts or individual case studies, with limited systematic investigation of the energy-saving mechanisms across different climate zones in China. Comparative analyses based on Chinese building energy-efficiency standards remain particularly insufficient. This study investigates four representative Chinese cities corresponding to major climate zones—Harbin, Beijing, Shanghai, and Guangzhou—as research cases. A parametric office-building model was developed using the Ladybug–Honeybee simulation platform to evaluate annual cooling and heating energy consumption under different window-to-wall ratios (WWRs = 0.2, 0.4, and 0.6) and south-facing façade tilt angles ranging from 0° to 25°. A simplified thermal calculation model incorporating envelope heat transfer and solar heat gain was further combined with multiple linear regression analysis to examine the driving factors behind energy-consumption variations across climate zones. The results indicate that the energy-saving effectiveness of tilted façades decreases with decreasing latitude. During the cooling season, high-latitude cities exhibit the greatest reduction in cooling demand, with Harbin showing a maximum energy saving exceeding 16%, whereas Guangzhou shows a reduction of only approximately 5%. During the heating season, the tilted façades lead to a certain increase in energy consumption, but this adverse effect also diminishes with decreasing latitude. In terms of annual overall energy performance, Beijing, Shanghai, and Guangzhou achieve total energy savings of approximately 4–5%, while Harbin in the severe cold zone shows limited overall benefits. An analysis of solar radiation characteristics reveals that tilted façades substantially reduce direct solar radiation (by approximately 90%), thereby decreasing total solar heat gain, a trend that aligns closely with the reduction in cooling energy consumption. Moreover, higher window-to-wall ratios are associated with greater energy-saving effects, indicating that outwardly inclined façades are more suitable for office buildings with relatively large glazed areas. Overall, the energy-saving potential of tilted façades is primarily influenced by solar radiation conditions and the balance between cooling and heating demands. Such façades demonstrate good application value in regions with relatively balanced cooling and heating demands or cooling-dominated climates, whereas their application in severe cold regions requires more comprehensive evaluation. This study establishes an analytical framework for assessing the energy performance of tilted façades across different climate zones in China, providing theoretical support and design guidance for climate-adaptive design and form-based energy optimization. Full article

Sodium-ion batteries (SIBs), owing to their cost-effectiveness and outstanding thermal safety, show great promise for energy storage applications, which is essential for improving the comprehensive utilization of renewable energy and advancing sustainable energy development. However, the thermal management technologies for SIBs have failed to attract enough attention for further research. Herein, temperature rise experiments of SIBs were carried out to explore their heat generation and transfer characteristics. The voltage and temperature rise characteristics, internal resistance, and entropy heat coefficient were investigated under various environmental temperatures and charge/discharge rates. Based on these findings, a thermal model was established according to the Bernardi theory. This model accurately describes the thermal behavior during the discharging process, enabling the prediction of heat generation in SIBs. The optimal air-cooled structure and operating condition parameters for the SIB pack were obtained using an orthogonal numerical optimization design. After optimization, the maximum temperature of the single cell is reduced by 7.76 °C, which is followed by a decrease of 21.33%. The average temperature difference of the SIB pack is 0.97 °C, which is reduced by 73.30%. This research is conducive to effectively controlling battery temperature within an optimal range to prevent combustion, explosion, and other thermal runaway events, providing a certain support for thermal management design for SIB packs in practical applications. Full article

A computational fluid dynamics (CFD) analysis is conducted to systematically investigate heat transfer enhancement in tubes fitted with grooved twisted tapes and to identify the groove geometry that provides the best thermo-hydraulic performance. Three grooved twisted tape configurations—circular-grooved twisted tapes (CGTT), rectangular-grooved twisted tapes (RGTT), and triangular-grooved twisted tapes (TGTT)—are evaluated and compared with a smooth tube and a conventional twisted tape over a Reynolds number range of 5000–20,000 under isothermal wall conditions. The grooved twisted tapes enhance heat transfer through the combined effects of swirl-induced secondary flows and groove-generated flow disturbances, which intensify turbulent mixing and reduce the thickness of the thermal boundary layer. Compared with the plain tube, the grooved configurations increase the Nusselt number by 1.472–1.98 times while increasing the friction factor by 3.21–3.58 times. Relative to the conventional twisted tape, the grooved designs provide an additional 8.0–12.1% enhancement in heat transfer with only a marginal increase of 0.2–1.5% in friction factor. The thermodynamic analysis indicates that the CGTT configuration exhibits the lowest entropy generation rate and exergy loss throughout the investigated Reynolds number range. In particular, the CGTT achieves a Bejan number of 0.999841 at Re = 5000, demonstrating an excellent balance between heat transfer enhancement and frictional losses. Furthermore, the CGTT attains the highest thermal performance factor (TPF) of 1.294 at Re = 5000 and maintains TPF > 1.0 over the entire Reynolds number range. The overall performance ranking is consistently established as CGTT > TGTT > RGTT based on comprehensive analyses of velocity fields, streamline patterns, turbulent kinetic energy distributions, temperature contours, and thermodynamic characteristics. Although the present study identifies the circular-groove configuration as the optimal design for a twist ratio (y/W) of 3.0, further parametric investigations involving variations in twist ratio, groove dimensions, and groove pitch are required to develop generalized design guidelines. Full article

In view of the frequent occurrence of trapped annular pressure and the increasingly prominent risk of wellbore integrity under the periodic high-intensity injection and production conditions of gas storage wells, a trapped annular pressure prediction model suitable for deep gas storage wells is established based on the comprehensive heat transfer characteristics of the tubing string-cement sheath-formation. The calculation results of the model are in good agreement with field-measured pressure data, with a coincidence degree of about 95%. Based on the established model, the influence laws of four major factors, including tubing specification and dimension, thermophysical properties of annular fluid, casing material characteristics and daily gas production rate, on trapped annular pressure are systematically analyzed. Meanwhile, the pressure control effects of three measures, namely Annulus A pressure relief, application of insulated tubing and nitrogen injection into Annulus B, are quantitatively compared for the case well. The research results show that adopting tubing with larger outer diameter and thinner wall thickness, injecting fluid with lower thermal expansion coefficient or higher isothermal compressibility coefficient into the annulus and appropriately reducing daily gas production can effectively decrease trapped annular pressure. Among them, the influence of fluid properties on trapped annular pressure is far greater than that of pipe material parameters. Among the three pressure control measures, nitrogen injection into Annulus B presents the optimal pressure control effect; when the nitrogen volume accounts for approximately 3% of the total annular fluid volume, the trapped annular pressure is reduced by about 82%. The research findings provide a theoretical basis and technical guidance for the prediction and control of trapped annular pressure in gas storage wells. It is recommended to prioritize the nitrogen injection technology for Annulus B in the well construction stage, and realize pressure management for producing wells by combining Annulus A pressure relief and production regulation. Full article

Effective thermal management is crucial for the performance, thermal safety, and lifespan of lithium-ion batteries in electric vehicles (EVs). Thermal management strategies are essential for preventing overheating, thermal imbalance, and the associated risk of thermal runaway. Nanofluids are emerging and attracting considerable attention as potential coolants for high-power energy storage and electronics systems. This review updates and summarizes the most recent advances in nanofluid-based cooling strategies for battery thermal management systems (BTMSs) over the past five years, emphasizing their implications for battery thermal safety. Three main nanofluid-based cooling strategies have been evaluated in depth, including nanofluid-based indirect liquid cooling, nanoparticle-enhanced PCM cooling, and nanofluid-based heat pipe cooling. Various nanofluid formulations, including mono, hybrid, and ternary nanofluids, have been considered and evaluated for their heat dissipation under high charge/discharge and abuse-relevant conditions. Thermal and hydraulic performance characteristics, including maximum temperature, maximum temperature difference, and pressure drop, have been comprehensively evaluated for different nanofluid-based cooling strategies. The findings demonstrated that nanofluids significantly improved heat transfer rates and enhanced temperature control efficiency. In particular, hybrid and ternary nanofluids exhibit superior thermal performance and effectively suppress the escalation of safety-critical temperatures. Beyond summarizing cooling performance, this review further discusses the role of nanofluid-based cooling strategies as functional thermal-control layers within intelligent BTMS architectures. Particular attention is given to their compatibility with sensing networks, BMS-/VCU-level supervisory control, predictive thermal models, actuator responsiveness, fault-warning algorithms, and long-term reliability under realistic driving and fast charging conditions. Therefore, this review provides architecture-oriented insights for developing safe, energy-efficient, and control-ready BTMSs for next-generation high-power and connected EVs. Full article

Conventional solar power tower (SPT) systems often suffer from significant heat transfer exergy destruction due to large temperature differences between the heat source and the working fluid during the heat exchange process. To overcome this limitation, a high–low dual-tower configuration based on segmented thermal utilization is proposed. In this arrangement, the high-temperature tower is mainly responsible for the evaporation, superheating, and reheating processes, whereas the low-temperature tower primarily handles feedwater preheating. Such a configuration improves the temperature matching characteristics during the heat exchange process. A comprehensive model integrating the heliostat field, receiver, thermal energy storage system, and power block was developed and validated against Solar Two experimental data, showing good agreement. Comparative analyses were conducted under identical solar resource and operating conditions. The results indicate that the proposed system achieves a comparable power output while reducing total heat transfer exergy destruction by approximately 24%, with a significant reduction of over 80% in the preheating section. Sensitivity analysis further reveals that optimizing the high tower outlet temperature can effectively reduce irreversibility and slightly enhance power output, although constrained by the pinch temperature difference. Dynamic simulations based on typical meteorological year data demonstrate that the system maintains stable operation and improves cycle efficiency. From an economic perspective, the proposed system reduces the levelized cost of electricity (LCOE) by about 6.6% and shortens the dynamic payback period, indicating enhanced long-term competitiveness. Overall, the high and low dual-tower system effectively improves thermodynamic and economic performance, providing a promising approach for high-efficiency concentrating solar power (CSP) development. Full article