The Hybrid 1D/2D flow model for non-Newtonian fluids in a single cavity die with a slit is presented. The equations of mass and momentum in a cavity are treated one-dimensionally by assuming an appropriate mean flow over the cross section of the flow. The governing equations inside the slot are treated two-dimensionally by the lubrication theory and assuming an appropriate mean flow. The equations of flow for the cavity and the slot are derived and then coupled. We use a finite element method to solve these governing equations. It is concluded that slot's geometry, fluid properties and machining accuracy affect the uniformity of the flow from the slot.

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Influence of interaction with a tangential lean blade and a box type casing on blade passing frequency (BPF) noise level in small axial-flow fans was investigated by measurement and computational fluid dynamics (CFD). Noise level of five fans having different tangential lean angles was measured. By increasing tangential lean angle, BPF noise level and broadband noise level reduced. An unsteady CFD simulation of tangential lean angle 31-degrees and 63-degrees was conducted to analyze the cause of BPF noise reduction. By increasing tangential lean angle, the inward blade force of the 63-degrees blade was increased compared to the 31-degrees blade. The increase of the inward blade force decreased centrifugal flow in radial direction at the exit of casing, because the inward blade force gave a momentum to the flow in radial inward direction. The decrease of the centrifugal flow suppressed interaction of the flow with the casing wall. The suppression of the interaction reduced static pressure fluctuation for BPF of the casing wall. The reduction of static pressure fluctuation for BPF was found to have a great influence on the BPF noise reduction. It is therefore clarified that increasing tangential lean angle was effective in reduction of the BPF noise.

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The cavitation surge is a kind of instability phenomenon generated in a liquid rocket engine, and it is known that when the inlet pressure of the turbopump of the engine is decreased, the frequency of cavitation surge continuously varied. On the other hand, it was observed in a turbopump test conducted in JAXA that the frequency of cavitation surge discontinuously decreased when the inlet pressure was decreased. Aiming at explaining this curious phenomenon, we conducted the linear analysis using the frequency-domain method and found that this phenomenon was a kind of self-excited vibration coupling the cavitation characteristics with the acoustic resonance of the inlet pipeline. However, the linear analysis could not simulate the phenomenon that a frequency of standing wave changed to the other mode at a certain inlet pressure. Therefore, we conducted the nonlinear analysis using the one-dimensional time-domain method. As a result, it was found that when the inlet pressure was decreased, the damping effect became larger in the higher frequency oscillation because of nonlinear factors. Consequently, the oscillation of higher frequency was intensely weakened and the oscillation of lower one appeared instead.

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We often perceive odors of smoking at seats for non-smokers of cafés and restaurants. A new ventilation system was developed by using the knowledge that neither flow separation nor backward flow could occur in case of increasing velocity distribution near walls. Air was supplied with uniform velocity distribution from the whole surface of one side wall and exhausted from the slits set at upper and lower positions of the opposite side wall. The effects were examined experimentally and by means of CFD, and it was confirmed that neither separation nor backward flow occurred even when furniture was set. Furthermore, it was examined experimentally and was confirmed that supplying unsteady flow was effective to prevent the growth of wakes behind obstacles and to decrease the amount of remaining smoke there, when Strouhal number based on the frequency of unsteady flow and the characteristic length of obstacle was about 0.2. These findings seemed useful to ventilate passenger cabins of airplanes or trains, where many seats were arranged densely.

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Fullerenes were generated and observed in the combustion processes of hydrocarbon fuel under low pressure conditions although the fullerene formation mechanism from PAHs in fuel rich hydrocarbon flames under low pressure conditions has not been clarified yet. In the present study, the effects of the residence time in the high temperature reaction field were investigated experimentally and the effects on the contents of fullerenes and PAHs were discussed with changing the residence time in the high temperature reaction field. The experimental results showed that the contents of fullerenes as well as PAHs in total soot collected from the flue gas decreased with the increase of the residence time in the range from 800 to 1500℃. On the other hand, the contents of fullerenes as well as PAHs in total soot decreased with the increase of the residence time over 1500℃ because the total PAHs contents in the flue gas increased under the present experimental conditions. It is essential for the high fullerene yields to realize the optimal residence time from 800 to 1500℃ as well as that over 1500℃ in the combustion process.

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Life cycle environmental evaluation of a new lightweight electric-assist tricycle has been discussed in terms of materials supply, production, use and the recycling/disposal stages. The effectiveness of such a novel tricycle is compared with existing transportation from the viewpoint of environmental impact. In the life cycle environmental evaluation, photovoltaic and in-vehicle fuel cell power generations are applied as an energy source for the electric-assist tricycle. Its transportation by light truck, passenger car and the well-known two-wheel electric-assist bicycle is discussed here for comparison. The environmental impact of the electric-assist tricycle, given its photovoltaic power supply, has a minimal environmental impact. The purchased electricity supply and in-vehicle fuel cell supply gradually greatly increased. The material supply and production stages of the electric-assist tricycle account for a large proportion of the overall environmental impact. In addition, the new electric-assist tricycle and other transport means were compared in terms of environmental impact. The factors affecting the environmental impact of each type of transportation device were shown. Then the optimum transport means is proposed suitable for the loadage and the time required in terms of environmental impact. As a result, our novel lightweight electric-assist tricycle was found to be effective for short-distance transport of a small amount of materials, as in a factory or for local transportation.

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The main objective of the research is to develop a bottom-up energy-economic model considering endogenous technical progress, and to analyze the potential of CCS introduction among Japan's electricity market in order to find out an optimum carbon reduction scenario into the future. On the basis of two-factor learning curve, both learning-by-doing and R&D functions drive technical progress in the model. The analysis is performed with a set of scenarios based on alternative assumptions for technical progress of carbon capture technologies: chemical absorption and physical absorption. As a result, technical progress decreases generation costs of power technologies with CCS systems resulting in the acceleration of additional CCS introduction. In addition, generation cost with chemical absorption notably decreases due to technical progress, and share of gas-fired power plant in total power generation increases. Thus, carbon emissions reduction reaches around 17% of total carbon emissions in 2050 under projected scenario, however, technical progress has little impact on total systems cost. Technical progress by learning-by-doing has a strong impact on CCS introduction than that of R&D. Moreover, unconsidered factors such as R&D effort in private sectors and spillover may push down possible carbon emissions as well.

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[in Japanese]

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[in Japanese]

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