Experiments were carried out to investigate condensation of ethanol-water vapor mixtures on a vertical mini-tube with outer diameter of 1.032mm. The length, inter diameter of the tube was 110mm, 0.727mm, respectively....
Experiments were carried out to investigate condensation of ethanol-water vapor mixtures on a vertical mini-tube with outer diameter of 1.032mm. The length, inter diameter of the tube was 110mm, 0.727mm, respectively. The tests were performed at a wide range of ethanol concentrations (Cv=0%, 1%, 2%,5%) and varied velocity of vapor (Uv=2m/s, 4m/s, 6m/s) and pressure (Pv=31.2kPa, 47.4kPa, 84.5kPa). With the change of the vapor-to-surface temperature difference, the heat transfer coefficients revealed nonlinear characteristics with the peak values under all ethanol mass fractions of vapor. The heat transfer coefficients decreased with increasing ethanol mass fraction of vapor.
Ti(OC4H9)4 was used as the Ti precursor and titanium dioxide (TiO2 ) was prepared by sol-gel method. During the preparation process, Fe3+ was doped and different surfactants, such as SDS, PEG, CTAB, were added to impr...
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ISBN:
(纸本)9783037856062
Ti(OC4H9)4 was used as the Ti precursor and titanium dioxide (TiO2 ) was prepared by sol-gel method. During the preparation process, Fe3+ was doped and different surfactants, such as SDS, PEG, CTAB, were added to improve the photocatalytic activity of TiO2 . The effect of the different type of surfactants on the structure of Fe-doped TiO2 was discussed. The photocatalysts were characterized by thermogravimetric thermal analysis, X-ray diffraction, scanning electron microscopy and UV-Vis spectrophotometer. The red shift of the absorption edge of the Fe-doped TiO2 prepared by using different surfactants was observed. Methyl orange (MO) solution was degraded under sunlight irradiation to evaluate the photocatalytic performance. The results indicated that the photocatalyst prepared with PEG addition had the highest activity and MO degradation ratio could reach 90% after 4 hours irradiation with the best photocatalyst.
Experiments were carried out to investigate condensation of ethanol-water vapor mixtures on a vertical mini-tube with outer diameter of 1.032 *** length,inter diameter of the tube was 110 mm,0.727 mm,*** tests were pe...
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Experiments were carried out to investigate condensation of ethanol-water vapor mixtures on a vertical mini-tube with outer diameter of 1.032 *** length,inter diameter of the tube was 110 mm,0.727 mm,*** tests were performed at a wide range of ethanol concentrations(Cv=0%,1%,2%,5%) and varied velocity of vapor(Uv=2m/s,4m/s,6m/s) and pressure(Pv=31.2kPa,47.4kPa,84.5kPa).With the change of the vapor-to-surface temperature difference,the heat transfer coefficients revealed nonlinear characteristics with the peak values under all ethanol mass fractions of *** heat transfer coefficients decreased with increasing ethanol mass fraction of vapor.
A comprehensive performance evaluation index that reflects the heat transfer capacity of the metal hydrides reactor was introduced, and some advantages of this index were discussed. A mathematical model of hydrogen ad...
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A comprehensive performance evaluation index that reflects the heat transfer capacity of the metal hydrides reactor was introduced, and some advantages of this index were discussed. A mathematical model of hydrogen adsorption and desorption was set up, and the validity of the model was confirmed by experimental data reported in literatures. Numerical simulations about working processes of two types of classical reactors (tubular and disc reactor) were performed. The results of comparative study show that the new index can be used in a quantitative evaluation of the reactor performance, and it is more reasonable than traditional ones.
Droplet evaporation is one of the important physical processes in liquid spray. Various models have been formulated in literature to compute the mass flow rate of droplet evaporation. It is found that all these models...
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Droplet evaporation is one of the important physical processes in liquid spray. Various models have been formulated in literature to compute the mass flow rate of droplet evaporation. It is found that all these models can be written in a single formulation, with various models represented by different expressions in the driving force HM, which can be classified into three kinds, namely, classical model, mass analogy model and drift-flux model. In this paper, we perform an analysis of the assumptions involved in the derivation of the three kinds of models, and find that the drift-flux model, which takes into account the effects of Stefan flow and corrective mass transfer, is the correct expression, while the classical model ignores Stefan flow effect and the mass analogy model ignores transient effect. Then the influence of mass driving force HM on droplet evaporation is analyzed, and it is concluded that both the classical model and the mass analogy model underestimate the effect of evaporation especially at high evaporate rates.
Nucleate pool boiling heat transfer of micro-pin-fined surface structure is proposed for efficiently cooling electronic components with high heat flux in microgravity,and verified by experiments performed utilizing th...
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Nucleate pool boiling heat transfer of micro-pin-fined surface structure is proposed for efficiently cooling electronic components with high heat flux in microgravity,and verified by experiments performed utilizing the drop tower ***-pin-fins with the dimensions of 50μm×120(am （thickness×height）(denoted as Chip PF50-120) and the space of 50μm were fabricated on the chip surface by dry etching ***-72 was used as working *** pool boiling on a smooth surface was also tested for *** were conducted in terrestrial gravity before the release of the drop capsule and in short-term microgravity during the free falling in the drop tower Beijing. The facility satisfied the safety criteria to expose the apparatus in the drop capsule to different gravitational environments varying between microgravity（μg）(10-10 g,g=9.81 m/s) in the free falling period and high-g level in the deceleration recovery system（16 go）.
We use non-equilibrium molecular dynamics simulations to calculate the self-diffusion coefficient, D, of a Lennard Jones fluid over a wide density and temperature range. The change in self-diffusion coefficient with t...
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We use non-equilibrium molecular dynamics simulations to calculate the self-diffusion coefficient, D, of a Lennard Jones fluid over a wide density and temperature range. The change in self-diffusion coefficient with temperature decreases by increasing density. For density ρ＊ = ρσ3 = 0.84 we observe a peak at the value of the self-diffusion coefficient and the critical temperature T＊ = kT/ε = 1.25. The value of the self-diffusion coefficient strongly depends on system size. The data of the self-diffusion coefficient are fitted to a simple analytic relation based on hydrodynamic arguments. This correction scales as N-α, where α is an adjustable parameter and N is the number of particles. It is observed that the values of a 〈 1 provide quite a good correction to the simulation data. The system size dependence is very strong for lower densities, but it is not as strong for higher densities. The self-diffusion coefficient calculated with non-equilibrium molecular dynamic simulations at different temperatures and densities is in good agreement with other calculations fronl the literature.
Boiling is a very complex and illusive process with very high efficiency of heat *** many sub-processes in boiling phenomenon,gravity can be involved and play much important *** reveal its influence,long-term,steady m...
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Boiling is a very complex and illusive process with very high efficiency of heat *** many sub-processes in boiling phenomenon,gravity can be involved and play much important *** reveal its influence,long-term,steady microgravity are ***,the opportunity is much ***,ground-based short-term microgravity experiment becomes an attractive alternative. Experiments of transient pool boiling of highly subcooled FC-72 on a smooth silicon chip with the dimensions of 10×10x0.5 mm3 were studied in short-term microgravity condition utilizing the drop tower *** heating currents were switched on near the release of the drop *** bubble behaviors and heat transfer of air-dissolved FC-72 on the silicon chip were obtained at the bulk
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