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41.
《International Journal of Hydrogen Energy》2022,47(7):4472-4488
As one of the cleanest energies, hydrogen has attracted much attention over the past decade. Hydrogen can be produced using water electrolysis in a Proton Exchange Membrane Electrolysis Cell (PEMEC). In the present study, the performance of the PEMEC, powered by the Photovoltaic-Thermal (PVT) system, is scrutinized. It is considered that the PVT system provides the required electrical power of the PEMEC and preheats the feedwater. A comprehensive numerical model of the coupled PVT-PEMEC system is developed. The model is used to investigate the effect of various operating parameters, including solar radiation intensity, inlet feedwater temperature, and feedwater mass flow rate, on the hydrogen production and operating voltage of the PEMEC at various Exchange Current Densities (ECDs). Furthermore, the effect of integration of Phase Change Material (PCM) and Thermoelectric Generator (TEG) on the hydrogen production of the system is evaluated. According to the obtained results, the PVT-TEG-PEMEC system outperforms other systems in hydrogen production. However, integration of the PVT-PEMEC system with PCM has a negligible effect on its hydrogen production. 相似文献
42.
43.
海上稠油热采开发过程中,通常采用蒸汽吞吐的方式进行原油开采。为满足稠油热采长效密封要求,研制了HPHT-215型热采防砂封隔器。封隔器胶筒采用特制的氟硅基复合材料+玻璃纤维网结构,并开展了材料性能评价测试。通过有限元分析和室内胶筒组合测试,对胶筒材料和组合结构进行了评价优化。室内全尺寸整机测试表明:封隔器能够满足耐温350 ℃、耐压21 MPa密封性能要求,并开展了高低温多轮次密封性能评价测试。该型热采防砂封隔器的研制成功,为海上稠油蒸汽吞吐多轮次开发提供了保障,具有广泛的应用前景。 相似文献
44.
《International Journal of Hydrogen Energy》2022,47(63):27199-27222
In this present work, the effect of lanthanum oxides (La2O3) on the thermal cycle behavior of TBC coatings and mechanical properties such as adhesion strength and microhardness of 8% Yttria Stabilized Zirconia (8YSZ) TBCs were investigated. CoNiCrAlY and aluminium alloy (Al–13%Si) were used as bond coat and substrate materials. 8YSZ and different wt % of La2O3 (10, 20, and 30%) top coatings were applied using the atmospheric plasma spray (APS) method. The thermal cycling test for TBC coated samples were conducted at 800 °C in the electric furnace. The XRD pattern shows that the La2O3 doped 8YSZ material transformed to cubic pyrochloric structured La2Zr2O7 during thermal cycling. Further, the Taguchi-based grey relation analysis (GRA) method was applied to optimize the TBC coating parameters to achieve better mechanical properties such as adhesion strength and microhardness. And the optimized La2O3/8YSZ TBC coating was coated on CRDI engine combustion chamber components. The engine was tested with microalgae biodiesel and hydrogen, and the results were promising for the TBC-coated engine. The engine performance increased while using La2O3/8YSZ coated components, and the emissions from engine exhaust gas such as CO, HC, and smoke reduced considerably. It was found that there was no separation crack and spallation of the coating layer in the microstructure. Ultimately, the microstructural analysis of the optimized TBC coated piston sample after 50 h of running in the diesel engine confirmed that the developed coating had a superior thermal insulation effect and longer life. 相似文献
45.
Anton Venter Hennie Fisher Gary I. Stafford Kwaku Gyebi Duodu 《International Journal of Food Science & Technology》2022,57(7):4347-4355
This study determined the anthocyanin profile of pigmented flower extracts from some Geraniaceae and Lamiaceae plant species found in South Africa, and their thermal and oxidative stability to assess their potential food application. Anthocyanins in the Geraniaceae (Pelargonium grandiflorum Willd. and Pelargonium × hortorum L.H. Bailey, Pelargonium zonale hybrid) were 3,5-diglucosides of delphinidin, petunidin, pelargonidin, peonidin and malvidin and acetyl-acylated malvidin, delphinidin and petunidin. The Lamiaceae species (Salvia aurea × dolomitica Bae’s blue, Salvia dolomitica Codd and Plectranthus zuluensis T. Cooke) mainly contained rutinosides of pelargonidin, glucosides of petunidin, pelargonidin and p-coumaric acid- and malonyl-acylated delphinidin and malvidin. Lamiaceae pigments had higher thermal and oxidative stability. This could be due to aromatic malonyl-acylated anthocyanin self-association and strong intermolecular interactions with phenolic acids and derivatives. Flowers from Lamiaceae and Geraniaceae have potential application as natural food colourants, but temperature and oxidising conditions must be considered depending on the particular species being used. 相似文献
46.
《Advanced Powder Technology》2022,33(11):103817
The heat production and thermal storage characteristics of rapid-preparation amorphous powder activated coke (RAC) were investigated. RAC was prepared by using a drop-tube reactor system. The natural oxidation characteristics of RAC were studied through combined TG–FTIR analysis and temperature-programmed experiment. Experimental results showed that CO and CO2 were the main oxidation products of RAC in air, and that the oxidation reaction was in accordance with the Arrhenius equation and law of mass action. Thermal storage characteristics were studied through computational fluid dynamics simulation. The maximum excess temperature θmax increases linearly with the increase of the initial temperature. The concentration fields of the products show that CO2 is mainly concentrated in the upper part of the coke bin, and the CO generated by CO2 at high temperature is mainly concentrated in the central part of the coke bin. 相似文献
47.
《Advanced Powder Technology》2022,33(12):103879
Heat transfer within ceramic feedstock powders is still unclear, which impedes optimization of the thermal and mechanical properties of the thermal sprayed coatings. The microspheres (yttria-stabilized zirconia YSZ and lanthanum zirconate LZO) were prepared via the electro-spraying assisted phase inversion method (ESP). The thermal properties of the two ESP microspheres and a commercial hollow spherical powder (HOSP) were investigated by using theoretical, experimental, and simulation methods. Thermal conductivity of the single microsphere was estimated via a novel nest model that was derived from the Maxwell-Eucken 1 and the EMT model. Thermal conductivity of a single YSZ/LZO-ESP microsphere prepared at 1100–1200 °C was within 0.36–0.75 W/m K, which was ~ 20 % lower than that of a single YSZ-HOSP microsphere with a similar porosity. Heat flux simulation showed that high tortuosity around the multi-scaled voids of the ESP microsphere led to a more efficient decrease in thermal conductivity compared with total porosity. 相似文献
48.
《International Journal of Hydrogen Energy》2022,47(80):34244-34256
A conducting and anticorrosive coating is crucial for the application of metal bipolar plates (BP) in proton exchange membrane fuel cell (PEMFC). In this work, a Ti3C2Tx (T)-carbon black (C)-acrylic epoxy (AE) coating is prepared on 304 stainless steel (SS) with enhanced corrosion resistance and conductivity. The corrosion resistance of the T-C-AE coating is investigated in a 0.5 M H2SO4 solution as compared to the AE, T, and T-AE coatings. The T-C-AE coated 304SS exhibits the strongest corrosion resistance with the most positive corrosion potential and the lowest corrosion current density of 0.00673 μA cm?2 in all the samples, while retaining intact and compact surface morphology with the lowest metal ion dissolution even after immersed for 720 h. The addition of Ti3C2Tx and carbon black into the AE matrix greatly decreases interfacial contact resistance (ICR), and the T-C-AE coating achieves a low ICR of 15.5 mΩ cm?2 under 140 N cm?2 compaction force. The excellent anticorrosion performance is mainly attributed to the physical barrier and the cathodic protection provided by the stacked Ti3C2Tx (MXene) nanosheets in the T-C-AE coating. This eco-friendly, conducting, and anticorrosive T-C-AE coating has a good application prospect on SS BP of PEMFC. 相似文献
49.
In the present numerical study, the combined effect of temperature-dependent thermal conductivity, linear thermal radiation, and magnetic effect on shear-thinning tangent hyperbolic fluid past a sensor surface has been studied. After converting the modelled partial differential equations into ordinary differential equations by using similarity transformation, the system of equations is tackled with the aid of the shooting method. The influence of important parameters on the fluid motion and energy distribution is displayed graphically and analyzed in detail. The presented simulations depict that a significant rise in fluid velocity is noticed for an enhancement in the magnetic parameter while an opposite trend is observed for the temperature distribution. Moreover, the skin friction coefficient decreases as the squeezed flow index is increased. 相似文献
50.
The dependence of the maximum and minimum wet thicknesses on the coating gap is derived for the slot-die coating process, under different slot-die configurations. Analytical expressions for the wet thickness and its derivative with respect to the coating gap are obtained using a simple flow model. The results indicate that, as expected, the minimum wet thickness increases linearly with the coating gap; however, the maximum wet thickness demonstrates a counterintuitive trend of decreasing as the coating gap increases, when a specific slot-die configuration is assumed. Moreover, the results are also validated by numerically solving the complete two-dimensional (2D) Navier–Stokes equation. 相似文献