α-Fe2O3 nanorod arrays were fabricated by a low-temperature aqueous chemical growth (ACG) technique and followed by an annealing process. For the surface doping of α-Fe2O3 nanorods, β-FeOOH nanorods obtained via AC...
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Radiation distribution study is of importance for the design and the optimization of fluidized photocatalytic tubular reactor which has been developed for photocatalytic hydrogen production under direct solar light. I...
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Radiation distribution study is of importance for the design and the optimization of fluidized photocatalytic tubular reactor which has been developed for photocatalytic hydrogen production under direct solar light. In the present study, the radiation distribution in such reactor was successfully simulated by adopting Monte Carlo method and the six-flux radiation absorption-scattering models. Both the incident angles of light around the reactor and the concentration distribution of photocatalyst were taken into account. Our analysis indicates that the angles and the intensity of the incident rays significantly affect the radiation distribution. Moreover, it was also found that the equilibrium radiation distribution has a close relationship with the density distribution of the photocatalysts. The simulated results are expected to be helpful for obtaining the optimal operating parameters for solar photocatalytic hydrogen production.
A model for wave properties, such as wave velocity and amplitude in churn flow has been developed in this paper. The results demonstrate that the wave behavior differs from that in annular flow. In addition, the criti...
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A model for wave properties, such as wave velocity and amplitude in churn flow has been developed in this paper. The results demonstrate that the wave behavior differs from that in annular flow. In addition, the critical amplitude A c decreases with the increase in gas flow rate. Moreover, the maximum amplitude A max decreases with the increasing of gas mass flux but increase with the increasing of liquid mass flux. The average absolute deviations (AAD) for A c and A max are 16.29% and 7.10%, respectively.
In order to improve the accuracy of interface capturing and keeping the computational efficiency, an adaptive VOF method on unstructured grid is proposed in this paper. The volume fraction in each cell is regarded as ...
In order to improve the accuracy of interface capturing and keeping the computational efficiency, an adaptive VOF method on unstructured grid is proposed in this paper. The volume fraction in each cell is regarded as the criterion to locally refine the interface cell. With the movement of interface, new interface cells (0 ≤ f ≤ 1) are subdivided into child cells, while those child cells that no longer contain interface will be merged back into the original parent cell. In order to avoid the complicated redistribution of volume fraction during the subdivision and amalgamation procedure, a predictor‐corrector algorithm is proposed to implement the subdivision and amalgamation procedures only in empty or full cell ( f = 0 or 1). Thus volume fraction in the new cell can take the value from the original cell directly, and the interpolation of the interface is avoided. The advantage of this method is that the re‐generation of the whole grid system is not necessary, so its implementation is very efficient. Moreover, an advection flow test of a hollow square was performed, and the relative shape error of the result obtained by adaptive mesh is smaller than those by non‐refined grid, which verifies the validation of our method.
Radiation distribution study is of importance for the design and the optimization of fluidized photocatalytic tubular reactor which has been developed for photocatalytic hydrogen production under direct solar light. I...
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Radiation distribution study is of importance for the design and the optimization of fluidized photocatalytic tubular reactor which has been developed for photocatalytic hydrogen production under direct solar light. In the present study, the radiation distribution in such reactor was successfully simulated by adopting Monte Carlo method and the six-flux radiation absorption-scattering models. Both the incident angles of light around the reactor and the concentration distribution of photocatalyst were taken into account. Our analysis indicates that the angles and the intensity of the incident rays significantly affect the radiation distribution. Moreover, it was also found that the equilibrium radiation distribution has a close relationship with the density distribution of the photocatalysts. The simulated results are expected to be helpful for obtaining the optimal operating parameters for solar photocatalytic hydrogen production.
In this work a series of Eosin Y-ZnO(x%)/TiO2 were prepared. ZnO well dispersed on the surface of TiO2, which improves the adsorption of Eosin Y and the excited electron to transfer to the conduction band of TiO2. The...
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In this work a series of Eosin Y-ZnO(x%)/TiO2 were prepared. ZnO well dispersed on the surface of TiO2, which improves the adsorption of Eosin Y and the excited electron to transfer to the conduction band of TiO2. Therefore the visible light activity of 0.2%Pt-Eosin Y-ZnO(x%)/TiO2 is much higher than that of the 0.2%Pt-Eosin Y-TiO2 and 0.2%Pt-Eosin Y-ZnO. The 0.2%Pt-Eosin Y- ZnO(1.5%)/TiO2 has the highest visible light activity among the catalysts coupled with various ZnO amount, whose activity is increased by a factor of 3.5 compared to that of 0.2%Pt-Eosin Y-TiO2. It is proposed that, 0.2%Pt-Eosin Y-ZnO(1.5%)/TiO2 has the optimal trapping sites of carriers and thickness of the space-charge layer on the TiO2 particle surface, so these factors result a more efficient charge separation, an increased lifetime of the charge carriers, and the enhanced of hydrogen production.
The present work reports the renewable hydrogen production by an anaerobic photocatalytic reforming of formic acid over CdS sensitized Na2Ti2O4(OH)2 nanotubes. the Na2Ti2O4(OH)2 nanotube was prepared and charactered b...
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The present work reports the renewable hydrogen production by an anaerobic photocatalytic reforming of formic acid over CdS sensitized Na2Ti2O4(OH)2 nanotubes. the Na2Ti2O4(OH)2 nanotube was prepared and charactered by X-ray diffraction, UV-visible absorption, transmission electron microscopy, etc. The activity of the catalyst in formic acid was investigated. The greatest photocatalytic reforming activity of formic acid occurs as the formic acid initial concentration is 20 v.%. A probable mechanism for the photocatalytic reforming process was proposed and discussed.
An experiment has recently been completed at Xi'an Jiaotong University (XJTU) to obtain wall-temperature measurements at supercritical pressures with upward flow of water inside vertical annuli. Two annular test s...
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The Ni-doped (CuIn)0.2Zn1.6S2 photocatalysts were prepared via a two-step ultrasonic-hydrothermal method under an environmental-friendly condition. XRD pattern profiles suggested that Ni2+ successfully doped into (CuI...
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The Ni-doped (CuIn)0.2Zn1.6S2 photocatalysts were prepared via a two-step ultrasonic-hydrothermal method under an environmental-friendly condition. XRD pattern profiles suggested that Ni2+ successfully doped into (CuIn)0.2Zn1.6S2 lattice. UV-Vis spectra indicated that the optical properties of the photocatalysts greatly depended on the amount of Ni doped. SEM images show that the samples were microspheres. The microsphere structures were gradually damaged with the increment of Ni doping amount. The photoactivity of (CuIn)0.2Zn1.6S2 was enhanced when Ni2+ was doped into the crystal structure. The H2 evolution performance over the prepared samples from inorganic/organic sacrificial solution was systematic investigated.
Deposition of cement kiln ash on the tubes of heat recovery boiler affects the heat exchange efficiency. The basic characteristic of cement kiln ash and the deposition on the tubes with different arrangements are pres...
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Deposition of cement kiln ash on the tubes of heat recovery boiler affects the heat exchange efficiency. The basic characteristic of cement kiln ash and the deposition on the tubes with different arrangements are presented. Numerical simulation and experiment measurement show that flow field feature, especially the low-velocity zone and vortex street, causes different shape of ash deposit around the tube. The effect of ash concentration, tube arrangement and gas velocity on the deposition is analyzed. The effect of the tube diameter and the gas composition is also discussed.
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