The study of a droplet spreading on a circular cylinder under gravity was carried out using the pseudo-potential lattice Boltzmann high-density ratios multiphase model with a non-ideal Peng–Robinson equation of state...
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The study of a droplet spreading on a circular cylinder under gravity was carried out using the pseudo-potential lattice Boltzmann high-density ratios multiphase model with a non-ideal Peng–Robinson equation of state. The calculation results indicate that the motion of the droplet on the cylinder can be divided into three stages: spreading, sliding, and *** contact length and contact time of a droplet on a cylindrical surface can be affected by factors such as the wettability gradient of the cylindrical wall, the Bond number, and droplet size. Furthermore, phase diagrams showing the relationship between Bond number, cylinder wall wettability gradient, and contact time as well as maximum contact length for three different droplet sizes are given. A theoretical foundation for additional research into the heat and mass transfer process between the droplet and the cylinder can be established by comprehending the variable rules of maximum contact length and contact time.
Surficial redox reactions play an essential role in photocatalytic water splitting,and are closely related to the surface properties of a specific *** this work,using monoclinic BiVO_(4)decahedral single crystals as a...
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Surficial redox reactions play an essential role in photocatalytic water splitting,and are closely related to the surface properties of a specific *** this work,using monoclinic BiVO_(4)decahedral single crystals as a model photocatalyst,we report on the interrelationship between the photocatalytic activity and the surficial reaction sites for charge-carrier *** controlled hydrothermal synthesis,the ratio of{010}to{110}facets on BiVO_(4),which respectively serve as reductive and oxidative sites,is carefully *** results show that superior photocatalytic water oxidation could be obtained on BiVO_(4)decahedrons with a medium ratio of reductive/oxidative sites and that efficient overall water splitting could be achieved via further modification of appropriate cocatalysts in Z-scheme *** excellent photocatalytic performance is attributed to the accelerated selective redox reactions by realizing balanced charge-carrier consumption,which provides insightful guidance for prospering photocatalytic reactions in energy conversion.
Various Mn-based catalysts for NO oxidation were prepared using MnO_(x)as active compound,while Ti O_(2)and Al_(2)O_(3)were adopted as catalyst *** performance of the catalysts was tested to study the effect of suppor...
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Various Mn-based catalysts for NO oxidation were prepared using MnO_(x)as active compound,while Ti O_(2)and Al_(2)O_(3)were adopted as catalyst *** performance of the catalysts was tested to study the effect of support on Mn-based catalyst *** of the catalysts followed as Mn_(0.4)/Al>Mn_(0.2)/Al>Mn_(0.4)/Ti>Mn_(0.2)/Ti>MnO_(x)>Al_(2)O_(3)on the whole,indicating the synergism of MnO_(x)and Al_(2)O_(3)for NO catalytic *** were analyzed according to characterization *** oxygen on catalyst rather than lattice oxygen was detected as the active oxidizer for NO *** catalyst support,Al_(2)O_(3)provided more sites to carry surface adsorbed oxygen than TiO_(2),resulting in the presence of more active oxygen on Mn O_(x)/Al_(2)O_(3)than on MnO_(x)/TiO_(2).Moreover,MnO_(x)/Al_(2)O_(3)possessed high surface area and pore volume,which greatly benefited the adsorption of NO on catalyst and further favored the oxidation of NO by active *** these advantages helped Mn_(0.4)/Al exhibited the best catalytic efficiency.
The ability to unlock the interplay between the activity and stability of oxygen reduction reaction(ORR)represents an important endeavor toward creating robust ORR catalysts for efficient fuel ***,we report an effecti...
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The ability to unlock the interplay between the activity and stability of oxygen reduction reaction(ORR)represents an important endeavor toward creating robust ORR catalysts for efficient fuel ***,we report an effective strategy to concurrent enhance the activity and stability of ORR catalysts via constructing atomically dispersed Fe-Mn dualmetal sites on N-doped carbon(denoted(FeMn-DA)-N-C)for both anion-exchange membrane fuel cells(AEMFC)and proton exchange membrane fuel cells(PEMFC).The(FeMn-DA)-N-C catalysts possess ample dual-metal atoms consisting of adjacent Fe-N_(4)and Mn-N_(4)sites on the carbon surface,yielded via a facile doping-adsorption-pyrolysis *** introduction of Mn carries several advantageous attributes:increasing the number of active sites,effectively anchoring Fe due to effective electron transfer to Mn(revealed by X-ray absorption spectroscopy and density-functional theory(DFT),thus preventing the aggregation of Fe),and effectively circumventing the occurrence of Fenton reaction,thus reducing the consumption of ***(FeMn-DA)-N-C catalysts showcase half-wave potentials of 0.92 and 0.82 V in 0.1 M KOH and 0.1 M HClO_(4),respectively,as well as outstanding *** manifested by DFT calculations,the introduction of Mn affects the electronic structure of Fe,down-shifts the d-band Fe active center,accelerates the desorption of OH groups,and creates higher limiting *** AEMFC and PEMFC with(FeMn-DA)-N-C as the cathode catalyst display high power densities of 1060 and 746 mW cm^(-2),respectively,underscoring their promising potential for practical *** study highlights the robustness of designing Fe-containing dual-atom ORR catalysts to promote both activity and stability for energy conversion and storage materials and devices.
With the rapid scale-up in popularity of renewable energy sources, the new power system is suffering from enhanced *** order to improve flexibility of new power system and mitigate carbon emission, the integration of ...
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ISBN:
(纸本)9798331307660
With the rapid scale-up in popularity of renewable energy sources, the new power system is suffering from enhanced *** order to improve flexibility of new power system and mitigate carbon emission, the integration of thermal power plants with energy storage technologies (ESTs) has gradually become a promising *** a key support for the development of new power system, it is of great significance to investigate the capacity optimization of advanced ***, there was a lack of study related to the capacity optimization of ESTs and the combination revenue patterns of ESTs were seldom *** the present work, a capacity optimization model was established for ESTs operating in combination with thermal power plants on the generating side, including lithium iron phosphate battery (LIPB), vanadium redox flow battery (VRFB), compressed air energy storage (CAES), supercapacitors (SC), and flywheel (FE) with the goal of maximizing the ***, VRFB, and CAES energy storage systems were investigated in the peak shaving (PS) *** co-benefit of ESTs was significant, 30.7-43.2 $/MWh, internal rate of return (IRR) was 12%-20%, and payback period (PP) was 6-11 years when the ratio of ESTs allocation (EAR) for thermal power plants was 2.50%-5.52%.LIPB, VRFB, CAES, SC, and FE were investigated in the frequency regulation (FR) *** co-benefit of ESTs was 51.9-329.3 $/MWh, IRR was 20%-35%, and PP was 3-7 years when the EAR was 0.24%-5.65%.The contribution of carbon mitigation benefit to co-benefit for different ESTs varied substantially, ranging from 6.46% to 82.75%.The ESTs not only offered ancillary service, but also other services when it operated as an independent shared energy storage.A new combination revenue pattern was proposed, under which revenue increased by 35%-55% compared to that of existing *** analysis was performed, in which the cost of energy storage, carbon tax, peak-valley spread, and comprehensi
In this paper, the exergy efficiency of high-pressure heater feedwater in a coal-fired power generation thermal system heated with Therminol VP-1 as the thermal fluid is investigated, and the transient characteristics...
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The focus of this paper is on the measurement and calculation model of void fraction for the vertical upward co-current air-water slug flow in a circular tube of 15 mm inner diameter. High-speed photography and optica...
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The focus of this paper is on the measurement and calculation model of void fraction for the vertical upward co-current air-water slug flow in a circular tube of 15 mm inner diameter. High-speed photography and optical probes were utilized, with water superficial velocity ranging from 0.089 to 0.65 m·s^(-1)and gas superficial velocity ranging from 0.049 to 0.65 m·s^(-1). A new void fraction model based on the local parameters was proposed, disposing the slug flow as a combination of Taylor bubbles and liquid slugs. In the Taylor bubble region, correction factors of liquid film thickness Cδand nose shape CZ*were proposed to calculate aTB. In the liquid slug region, the radial void fraction distribution profiles were obtained to calculate aLS, by employing the image processing technique based on supervised machine learning. Results showed that the void fraction proportion in Taylor bubbles occupied crucial contribution to the overall void fraction. Multiple types of void fraction predictive correlations were assessed using the present data. The performance of the Schmidt model was optimal, while some models for slug flow performed not outstanding. Additionally, a predictive correlation was correlated between the central local void fraction and the cross-sectional averaged void fraction, as a straightforward form of the void fraction calculation model. The predictive correlation showed a good agreement with the present experimental data, as well as the data of Olerni et al., indicating that the new model was effective and applicable under the slug flow conditions.
Coal-fired power generation units are characterized by large inertia, strong coupling, and high delay, making dynamic characteristic modeling inherently complex and computationally intensive. To address this, this pap...
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In refrigerating industry,frost commonly deposits on the confined cold surfaces of heat exchangers,which affects the heat transfer *** the confined flow path of the heat exchanger,the frosting at downstream is affecte...
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In refrigerating industry,frost commonly deposits on the confined cold surfaces of heat exchangers,which affects the heat transfer *** the confined flow path of the heat exchanger,the frosting at downstream is affected by the parameters from the *** this study,a numerical model considering the confinement effect has been proposed to predict frosting characteristics in plate-fin heat ***-diffusion equations for humid air and empirical correlations for local frost density are employed in the numerical *** behavior and heat transfer in the confined channel are investigated with different humid air parameters and cold surface *** results indicate that frost thickness in the confined channel is thicker than that in open space under the same inlet *** frost layer is thicker and fluffier along the confined *** addition,the air temperature difference between inlet and outlet of the confined channel enlarges with *** the same average temperature of upper and lower surfaces,the heat and mass transfer of frosting are enhanced with diminishing temperature difference of upper and lower *** such condition,frosting is mainly influenced by the cold surface with the lower temperature.
The evolution and coverage of bubbles resulting from gas evolution at the reaction interface significantly impact mass transfer and the flow field within the photoelectrochemical water splitting system, posing a signi...
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The evolution and coverage of bubbles resulting from gas evolution at the reaction interface significantly impact mass transfer and the flow field within the photoelectrochemical water splitting system, posing a significant obstacle to overcoming the efficiency bottleneck of photoelectrochemical water splitting. In situ bubble observation can be realized via a coupled experimental system combining electrochemical measurements and high-speed imaging. The results indicate that bubble growth behavior correlates with system temperature and operating voltage; that is, the bubbles grow in an oscillating state on the electrode surface at the low operating voltage and high system temperature. Besides, the deviation amplitude of oscillating bubbles increases with system temperature yet decreases with operating voltage. The results indicate that the time coefficient of the growing bubble decreases, while the growth rate and gas evolution efficiency of the bubble increase with the increase of oscillating amplitude in the horizontal direction. The study of dynamic behaviors between the oscillating bubble and the contacted electrode reveals that the bubble oscillation is characterized by the periodic contraction and extension of the triple line. The mass transfer model of concentration boundary layer and the force model of oscillating bubble are constructed based on the interaction between the bubbles and the surrounding flow field. The mass transfer model has considered the microconvection caused by single-phase natural convection, gas-liquid interface expansion, and the oscillation of bubbles. Then through the force balance model, the solutal Marangoni force is found to gradually increase as the contact line extends outward.
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