The mechanism for transporting liquid from the bottom of the pipe to the top still to be established in the prediction of the film thickness distribution in horizontal annular two-phase flow. To resolve this issue, us...
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The mechanism for transporting liquid from the bottom of the pipe to the top still to be established in the prediction of the film thickness distribution in horizontal annular two-phase flow. To resolve this issue, using five parallel-wire conductance probes, time records of local liquid film thickness at five circumferential positions were collected. The characteristics of circumferential liquid film thickness profiles and its variation with gas and liquid velocities were obtained. The basic features of probability distribution function, probability density function, auto-correlation, cross-correlation and power spectrum density function of the disturbance waves in angular flow were studied respectively. The characteristics of circumferential profiles of disturbance waves and its variation with gas and liquid velocities were presented.
Propanol isomers are oxygenated fuels that have the potential to reduce the emission of engines. Particulate matter (PM) emissions of gasoline/propanol isomers blends have been comparatively investigated at different ...
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Propanol isomers are oxygenated fuels that have the potential to reduce the emission of engines. Particulate matter (PM) emissions of gasoline/propanol isomers blends have been comparatively investigated at different blending ratios of propanol isomers (0%, 10%, 20%, 40% and 100%) and EGR (Exhaust Gas Recirculation) rates (0% and 10%). Pure propanol isomers show significantly different emission characteristics compared to the other blends. PM number concentration decreases when EGR is introduced while little variation of PM mass concentration is observed. N-propanol mixtures produce higher PM number concentration than those of iso-propanol mixtures at the same blending ratio caused by their distinctively molecular structures and properties. The present study shows iso-propanol gives better performance as a gasoline additive compared to n-propanol.
Utilize the biomass energy and adopt carbon capture and storage technologies could reduce the CO2 emission effectively. Biomass gasification is an effective ways to use the biomass. Co-firing biomass syngas with pulve...
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The influence of γ-Al2O3/FC-72 nanofluids on pooling boiling heat transfer with a smooth surface was experimentally investigated. The fluorocarbon surfactant FSO-100 was also used in the experiment. In order to disti...
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The influence of γ-Al2O3/FC-72 nanofluids on pooling boiling heat transfer with a smooth surface was experimentally investigated. The fluorocarbon surfactant FSO-100 was also used in the experiment. In order to distinguish the effects of surfactant, four groups of contrast tests were designed as follows: base fluids (FC-72), base fluids with nanoparticles (γ-Al2O3+FC-72), base fluids with surfactant (FC-72+FSO-100) and nanofluids with surfactant (γ-Al2O3/FC-72+FSO-100). The results of nanofluids with surfactant showed that the heat transfer performance is enhanced compared with base fluid, but will weaken with the increase of particle concentration. In general, nanofluids can enhance the boiling heat transfer to some extent, and the enhancement is affected by the adjunction of surfactant and the sedimentation of nano-particules. Nanofluids prepared with only nanoparticles were not stable due to nonuniform distribution of the particles. The adjunction of surfactant (without nanoparticules) will lead to a significant deterioration in both heat transfer coefficient and CHF (Critical Heat Flux), but it can keep nanofluids stable and homogeneous to some degree for heat transfer enhancement.
Open cell metal foam can be applied to greatly improve thermal performance of heat sink and heat exchanger,so that it has been widely used in the fields of thermal(or heat)control system of aerospace vehicle and energ...
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Open cell metal foam can be applied to greatly improve thermal performance of heat sink and heat exchanger,so that it has been widely used in the fields of thermal(or heat)control system of aerospace vehicle and energy utilization system and become a very important topic for research in the aerospace thermophysics field,and more and more attentions have been *** optimal design of metal foam heat transfer devices is based on the understanding the flow and heat transfer characteristics in metal *** article reviews some recent progresses of theoretical and experimental researches on heat transfer enhancement and flow characteristics of metal *** found that the pore cell simplification models of metal foams generally fall into four categories,among which the most commonly used cell model is Kelivin *** exploratory works performed by the current authors are also introduced,such as the effect of boundary conditions on the heat transfer enhancement;the theoretical modelling of interfacial convective heat transfer taking into account heat conduction between foam ligaments;and the flow characteristics under relatively high *** analytical results show that the flow characteristics of metal foam at relatively high speed are completely different from those at low speed,a further thorough study of the heat transfer and flow characteristics of metal foam is necessarily *** this paper,two types of partial filling techniques are *** heat transfer performance of partially filled tubes was evaluated by both the performance evaluation criteria and the performance evaluation plot of enhanced heat transfer techniques oriented for *** results show that the filling type of metal foam have a significant impact on its heat transfer enhancement ***,the filling method of metal foam should be further studied,in order to optimize the thermophysical properties of heat transfer devices.
The production of hydrogen by photocatalytic decomposition of water using zinc tetrathiomolybdate catalyst was studied. Zinc tetrathiomolybdate catalyst was prepared by coprecipitation and hydrothermal method based on...
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ISBN:
(纸本)9781622765409
The production of hydrogen by photocatalytic decomposition of water using zinc tetrathiomolybdate catalyst was studied. Zinc tetrathiomolybdate catalyst was prepared by coprecipitation and hydrothermal method based on ZnSO 4 and self-prepared [NH4]2MoS4 crystal. It was characterized by XRD, XRF, BET and UV-Vis spectra. The photocatalytic activities of the catalysts were ascertained by the production of hydrogen in an aqueous Na2S-Na2SO3 solution under the ultraviolet and visible light irradiation. It was observed that the photocatalysts showed the visible-light photocatalytic activity, and the ZnMoS4 photocatalyst prepared under hydrothermal condition for about 24h had the highest activity.
There are over 100 million tons of semi-coke produced in China every year, and use of the semi-coke in utility coal-fired boilers is a promising approach. In this paper, a blending model of semi-coke and bituminous co...
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Photocatalytic water splitting by solar light and biomass gasification in supercritical water both are considered as the most promising routes for renewable hydrogen production. The waste liquid from biomass gasificat...
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ISBN:
(纸本)9781118205976
Photocatalytic water splitting by solar light and biomass gasification in supercritical water both are considered as the most promising routes for renewable hydrogen production. The waste liquid from biomass gasification in supercritical water contains various organic compounds which can act as electron donors in photocatalytic system. In the present work, we report the hydrogen production by the anaerobic photocatalytic reforming of waste liquid from biomass gasification in supercritical water over CdS sensitized Na 2Ti2O4 (OH)2 nanotubes, Various reaction parameters were investigated, such as different gasification temperature and the pH value of the reaction solution. It was demonstrated that gasification in supercritical water and photocatalytic water splitting can be coupled together.
Solid oxide fuel cells (SOFCs) have received considerable interest nowadays, because they promise greater electrical efficiency than that obtained by a conventional heat engine or other types of low temperature fuel c...
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The flow patterns and their transitions of oil-water two-phase flow in horizontal pipes were studied. The experiments were conducted in two kinds of horizontal tubes, made of plexiglas pipe and stainless steel pipe wi...
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The flow patterns and their transitions of oil-water two-phase flow in horizontal pipes were studied. The experiments were conducted in two kinds of horizontal tubes, made of plexiglas pipe and stainless steel pipe with 40 mm ID respectively. No. 46 mechanical oil and tap water were used as working fluids. The superflcial velocity ranges of oil and water were: 0.04-1.2m·s-1 and 0.04-2.2m·s-1, respectively. The flow patterns were identified by visualization and by transient fluctuation signals of differential pressure drop. The flow patterns were defined according to the relative distribution of oil and water phases in the pipes. flow pattern maps were obtained for both pipelines. In addition, semi-theoretical transition criteria for the flow patterns were proposed, and the proposed transitional criteria are in reasonable agreement with available data in liquid-liquid systems.
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