Mass transfer characteristics of a spray column used as a dehumidification and regeneration device is reported. The experiment was conducted by using air of known humidity and polyethylene glycol (PEG) as a desiccant solution, changing the process parameters including liquid flow rate, gas flow rate, water concentration of PEG, PEG temperature, and nozzle diameter. The performance of spray column was evaluated in terms of volumetric mass transfer coefficient. The result was correlated by the dimensionless groups including physical properties the liquid and nozzle diameter. The experimental and values obtained by the derived correlation agreed better than other correlations.

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This paper presents the experimental results for the elucidation of the thermal transport performance of fin with built-in self-oscillating heat pipe (OHP) as one of the effective thermal devices. The thin plate fin is made of brass having several turns of small channel. In this experiment, the effects of number of turns and working fluid were investigated. It was found that enhancement of self oscillating phenomenon and heat transport performance was obtained by the increase in the number of turns. Moreover, the performance of OHP was varied with working fluids due to their thermal properties.

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On March 11, 2011, a natural disaster created by earthquakes and Tsunami caused a serious potential of nuclear reactor meltdown in Fukushima due to the failure of emergency core cooling system using diesel generators. In this paper, heat pipe based emergency core cooling system has been proposed for nuclear power plants. The proposed heat pipe system will operate in fully passive mode with high runtime reliability and therefore provide safer operation of nuclear power plants. Based on the simulation model, it was estimated that, using proposed heat pipe system, the reactor water temperature can be reduced to below 100 ℃ in less than 12 hours.

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The new concept of emergency core cooling system without electric power supply is hoped after the accident at the first FUKUSHIMA power plant. The large earthquakes and the tremendous tsunami waves out of our prediction break down all electrical resources including the auxiliary power supply. The stopping process of atomic reactor was success, but the core cooling and the emissions enclosing process were failed. The present paper proposes the new emergency core cooling system without electric power by using the super-sonic two-phase flow ejector. The proposed system has two important features. One is that this system never bents out the radioactive steam into the surroundings. This function is completed by the super-sonic ejector. Both the driving and the sucked flows of the ejector can be compressed and flow back into the high pressure core-vessel. The other is that this system works without power by using the energy of the steam at high temperature. The paper shows the thermodynamics theory of the ejector system.

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Now, the lack of pure water is a serious problem in the world. One of the solutions is the desalination of seawater, and there are several ways, for example evaporation, membrane and freezing methods, but every method has the problem in construction and operating costs. This paper described a new desalination method and device by the liquid column of seawater and decompressed evaporation. At this time, the seawater at the top of the vessel set vertically is decompressed by the liquid column to the vacuum, and is boiled and evaporated. It is condensed by cooling and then the pure water is generated.

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Critical Heat Flux (CHF) in a non-uniformly heated tube under inclined upward flow conditions is very important factor in designing actual boiling systems. However, only a few investigations on the CHF have been conducted under these conditions. Consequently, in the series of investigations, the experimental study on the CHF of non-uniformly heated tube was conducted with 900 mm and 1800 mm in heated length under the inclined condition. In this study, the CHF experiment was conducted with 450 mm in heated length under several inclination angles, i.e. 15, 30, 45 and 90 degree. The characteristic of CHF is decided by the relation between the gravity and the liquid film lift up, and these effects have been able to be categorized by using the modified Froude number well.

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Dryout of counter-current two-phase flow is widely observed in the actual chemical and/or industrial systems. In case of the diabatic counter-current two-phase flow, the upward gas increases with the liquid film evaporation along the heating tube and flooding strongly affects the dryout of counter-current two-phase flow. In this investigation, the dryout experiment was conducted with the counter-current two-phase flow consisted of the free falling liquid film and upward gas flow. The obtained dryout characteristics were strongly influenced by the degree of inlet subcoooling, and are classified into three groups on the basis of the dryout mechanism.

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The dissipated effective energy in the refrigeration cycle can be recovered using the two phase flow ejector. Performance of the two phase nozzle plays an important role in developing the two phase flow ejector for the refrigeration cycle. It is important to know the efficiency of the two phase nozzles for refrigerant. The purpose of the present study is to elucidate the boiling phenomena in nozzle of the two phase flow of the refrigerant Isobutan. The experiment results shows that Isobutan have not so good boiling properties because the pressure distribution in nozzle don't much IHE model.

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There is still not enough knowledge of thermal-fluid characteristics in helically coiled tube under flow instability condition. In this investigation, experiment was conducted by using a natural circulation loop with liquid nitrogen as working fluid. The test section was helically coiled tube and had 4 mm in inner tube diameter, 100 mm in coil diameter and 3150 mm in heated length. The experimental condition was inlet throttle valve K_<in> = 540, 1076, 2065, and system pressure p_<ex> = 0.3, 0.5 MPa. As an experimental result, a inlet flow rate, boiling heat transfer and critical heat flux had been evaluated including post-dryout condition.

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Two phase flow distribution and the flow stability are substantial problems in designing heat exchangers with parallel-channel system. Fundamental experiment was conducted with air-water mixture in parallel-channels jointed sinuously in series. The observed flow-mal-distribution was serious at low volumetric fluxes of air and water. An installation of compressible volume upstream the mixing section brought about significant oscillation in the flow and pressure drop, mainly in the upper flow section. This oscillation was well-known pressure drop oscillation induced by dynamic interaction between negative resistance and the compressible capacity.

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An experimental study has been carried out on the synthesis of carbon nanomaterials using Ni catalyst and Fe/Mo catalyst in methane/air or ethylene/air laminar, fuel-rich premixed flames under atmospheric pressure. By placing a pair of porous media in the upstream and downstream sides of the combustion space, excess enthalpy burning was applied to the mixture. Effects of formed gases on nanomaterials growth have been investigated in this study. As a result, it has been clarified that carbon nanomaterials with a diameter of from 20 to 50 nm are synthesized in the downstream side of the exothermic reaction zone.

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Carbon nanotubes (CNT) were synthesized from size-classified catalyst metal nanoparticles to observe the effect of the nanoparticle's diameter on the diameter of the CNT. The nanoparticles were generated by laser vaporization and classified by a DMA (Differential Mobility Analyzer), which sorts them by diameter according to differences in electrical mobility. CNT were synthesized from these catalyst metal nanoparticles by using chemical vapor deposition (C_2H_2 is employed as a carbon sourse). CNTs and the particle diameter distributions of the metal nanoparticles were observed by TEM. It is found that particle diameter distributions of the metal nanoparticles are almost same with synthesized CNT. The effects of hydrogen on CNT synthesis is also studies and it is found that a concentration of hydrogen affect CNT growth significantly.

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The evolution characteristics of degradation gas from highly densified biomass briquette called Bio-coke (BIC) are experimentally and numerically investigated. In the present study, evolution rates of both volatile and water from the sample are determined as Arrhenius-type equations and the constants such as frequency factors and activation energies are given by the thermo-gravimetric analysis. It is confirmed that the model used in the study can qualitatively describe the gas evolution from the BIC sample. With high water content, the time volatile evolution start is delayed because much heat is consumed to evaporate the water. In the period before the volatile evolution start, the rate of evolved water to the whole water increases with increasing the water content of the BIC sample.

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The variation of surface characteristics of carbon blacks in methane catalytic decomposition process was investigated. Remarkable time variation of the methane decomposition rate was demonstrated and the influence of carbon deposition was suggested. Surface characteristics of carbon blacks were analyzed by nitrogen adsorption-desorption isotherms and transmission electron microscopy (TEM). Changes in the surface structural characteristics were evaluated by the specific surface area, the pore size distribution, and TEM images. The correlation between the catalytic activity and the surface characteristics was discussed.

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The authors develop a small and simple steam-reforming reactor in a home-use size for n-dodecane as a heavy-hydrocarbons fuel. Under the thermal condition controlled by electric heaters and a gas burner with a thermal diffuser, the authors measure the inside-temperature profile and the hydrogen molar fraction (concentration) C_<H2>, together with the molar fractions C_<CH4>,C_<CO> and C_<CO2> of other main gas components such as CH_4, CO and CO_2, respectively. As a result, the authors successfully achieve suitable inside-temperature profiles. In a previous study (Fujimoto et al., 2011), it have been experimentally shown that the effects of the liquid-hourly space velocity LHSV upon C_<H2>, C_<CH4>, C_<CO> and C_<CO2>, where conversion ratio becomes low at high LHSV's &ge; 1.0 h^<-1>. Thus, at LHSV = 1.0 h^<-1>, the authors reveal the effects of the temperature T inside the reactor upon the molecule ratios, comparing with a thermal-equilibrium theory.

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In order to enhance the efficiency of producing BDF, direct and indirect ultrasound-based BDF synthesis methods based on solid base catalysts were proposed and experimentally verified. BDF was successfully produced by these two methods. Theoretical air quantity and combustion temperature of BDF were also calculated.

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Experimental study has been conducted to produce the carbon dioxide hydrate in emulsions for improving a fluidity of the hydrate slurry. Water in oil emulsions composed of hydrocarbon and water solution doped with a small amount of surfactant were prepared by briskly mixing of homogenizer. Carbon dioxide absorption and hydrate production experiment was carried out for various chloride dissolution and hydrocarbon saturation at 275K under 3.0MPa. The result shows that the amount of Carbon dioxide absorption increases with the 5wt% NaCl in water whereas more than 10wt% NaCl addition decreases the Carbon dioxide absorption

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This paper describes residual hydrate dissociation in a storage tank by heat conduction simulation. The suitable hydrate storage tank is necessary in the project which is supply the fuel gas by marine transport of natural gas hydrate. The amount of hydrate in the tank will change on demand. Two dimensional heat equation was solved using an implicit finite difference method namely the Crank-Nicolson scheme and Gauss-Seidel iteration technique. Temperature and hydrate volume fraction in a tank are calculated. The results of simulation indicated that the volume fraction of hydrate dissociation increases gradually with the heat-receiving surface.

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Glucose is one of the dominant components in the lignocellulosic biomass. Hydrothermal decomposition of glucose is conducted at 673 K in the presence of acid (HCl) or base (NaOH) catalysts, which represent to the addition of H^+ and OH^-. The glucose solution (1.5 wt%) is gasified with catalyst 0.01 M (at room temperature) in a tubular reactor at 25 MPa. The addition of H^+ in hydrothermal gasification of glucose enhanced the formation of furfural and 5-HMF, which are ionic reactions. On the other hand, the addition of OH^- slightly promoted the gasification reaction, which is a radical reaction. The kinetic parameters of glucose decomposition pathways are also determined by assuming the first-order reaction.

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A novel type of simple reactor for hydrogen production from liquid methanol is proposed. The reactor consists of a small porous ceramic block that has a hole penetrating the center around which a platinum catalyst is supported. After impregnated the porous block with a sufficient amount of liquid methanol, the block is intensively heated by a wire coil heater set up in contact with the hole surface. Methanol is catalytically decomposed into hydrogen and carbon monoxide in the dried region of the block that forms in the proximity of the contacting wire, and then flows out into the hole. Liquid methanol is passively replenished from the outer surface of the block due to capillary suction and is preheated during flow toward the hole. The gas production rate increases significantly with the increase in the heating power and the resulting gas temperature.

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