【要素的】 解説 3巻3号(1989)  カプセル輸送; 管路輸送; シミュレーション;
Air flow in a pnematic capsule pipeline is numerically simulated by the method of characteristics in each region bounded by capsules and or fixed boundaries such as a pipe inlet or exit. Capsules are considered a point mass and as a moving discontinuity travelling using capsule velocity for calculation of air flow. Capsules are assumed to be driven by the pressure difference across the capsule. The influence of capsule trajectories on the characteristic curves is treated by _??_ method. By this calculation the pressure and velocity of air in a pipeline and each capsule trajectory are obtained as a function of time for several transport conditions, and comparison with measurements is discussed for some cases.
【要素的】 総説 5巻4号(1991)  ねじれ管; 水力・空気輸送;
In a spiral tube twisted with a constant pitch in relation to the axis, a swirling flow occurs when fluids flow in the tube. Solid particles in multiphase flows are mixed by the swirling flow. It has been established from the experimental results that the values of the critical velocity and the pressure loss decrease in comparison with these values in a circular pipe. Thus, the hold up phenomena of the multiphase flow does not occur in the spiral tube under a low velocity range. This review presents, the experimental data of the pressure drop and the velocity distribution of the single phase flow in the spiral tube, and the experimental results of the hydraulic and the pneumatic conveyance test of solid particles, respectively. It is pointed out that in practical application, the spiral tube presents a very useful method for preventing the holdup phenomenon in a transport pipeline for the hydraulic or pneumatic conveyance of highly concentrated solid particles.
【巨視的】 解説 7巻1号(1993)  カプセル輸送; トンネル;
Since the Pneumatic Capsule Pipeline System (PCPS) for the limestone transportation started its operation in 1983, PCPS has not had another opportunity of its application. Although it offers an automatic system which is both user-and environment-friendly, its high cost was thought to outweigh its merits. However, the need to find a way of cutting down on accidents, noise and dust in the construction industry became increasingly urgent. This led to the use of the PCPS in the construction of the Hokuriku Shinkansen's Akima Tunnel as the transportation sub system for the Extruded Concrete Lining Method (ECL Method), a fully automatic tunneling method capable of sovling the above mentioned problems. This PCPS transports ready-mixed concrete from the tunnel mouth to the tunnel head and, in the opposite direction, earth from the tunnel head to the disposal area which is 3 km distant from the tunnel mouth. It can transport 100m3/H of earth by launching a capsule train consisting of three (3) capsule vehicles every 2 minutes. It uses rectangular steel reinforced concrete pipe with an internal width of 900mm. The station inside the tunnel has to catch up with the excavating machine, which will progress about 7km in two (2) years. It is divided into three (3) units. The first unit discharges ready-mixed concrete from capsule vehicles and loads capsule trains with earth. The second goes back and forth between the first and the last unit and exchanges capsule trains with each other. The last, which is usually connected to the pipeline, receives and launches capsule trains. Traveling distance of the second unit increases as the excavating machine progresses. At certain intervals the second unit is disconnected from the pipeline and new concrete pipes are inserted between them. Since solving some teething problems the tunneling has progressed more than 1 km. PCPS applied tunneling is expected to spread widely in order to keep the construction environment safe and clean.
【巨視的】 特集 17巻1号(2003)  火力発電; 石灰石; 輸送;
【巨視的】 特集 17巻1号(2003)  LMG配管; クールダウン; 熱変形;
【巨視的】 特集 21巻1号(2007)  カプセル輸送;
【巨視的】 特集 23巻3号(2009)  輸送; 海洋; 船舶;
【巨視的】 特集 23巻4号(2009)  自動車; 交通;
The article describes the nature of highway traffic flow mainly composed of automotive four wheelers, and also introduces several technical issues to be solved by engineers. The one of the way of understanding the highway traffic flow is treated as continuous fluid flow, otherwise as dispersive individual vehicle movements. The short history of these two streams of traffic flow theories are reviewed, and the most basic diagrams useful in the analyses of highway traffic flow, such as time-space diagram, fundamental diagram and cumulative volume curve, are also introduced. One aspect of the classification of highways is the distinction of uninterrupted and interrupted flow facilities. The discharge flow from the stop line at one approach to a signalized intersection from the start of a displayed green traffic signal is the maximum flow for an interrupted flow highway facilities. The nature of 'traffic congestion', which is a typical phenomena occurred at a highway capacity bottleneck section, is discussed in general. The traffic flow is dealt as a two-phase flow with congested and uncongested flow regimes. The concept of 'traffic congestion' in an interrupted flow facilities are different from those in uninterrupted flow ones. As a simplification, Shock wave theory which can describe the direction and the wave speed of extension or diminution of the boundary of discontinuous different two highway traffic region, such as congested and uncongested traffic flow region, is introduced. The amount of excess traffic demand over a bottleneck capacity for recursive traffic congestion phenomena is also discussed.
【巨視的】 特集 27巻3号(2013)  水圧吸引; 土砂輸送; 固液二相流;
This paper shows Pipeline Sediment Transportation using HSRS ( Hydro-Suction sediment Removal Systems ) which is one of countermeasures for removable sedimentation in a dam reservoir. Since HSRS can also use power other than water head, it is the technology in which expansion of scopes, such as not only dam reservoirs but river channel, a seashore region, etc., is expectable. This paper is reported about the function of pipeline sediment transportation. Therefore, it reexamined about experiment data from a viewpoint of sediment discharge and flow state of sediment in a pipe-line.
【要素的】 特集 27巻3号(2013)  エマルジョン; 輸送; 圧力損失低減;
Oil spill response requires multiphase flow techniques in various aspects. Among them, methods for treating water-in-oil emulsion, which is often formed when oil spills on the sea surface, are very important. W/O emulsion drastically increases its viscosity and makes oil recovery operation very difficult. This paper presents friction loss reduction techniques in a pipeline flow as well as rheological behavior of the emulsion. For friction reduction, water injection and chemical surfactant injection were experimentally studied. It was found that the both methods can reduce the friction loss to a considerable extent. They were applied to practical use for oil recovery vessels.
【巨視的】 特集 27巻4号(2013)  航空; 交通;
In the current Air Traffic Management (ATM), pilots must fly following the instructions of air traffic controllers, who check the air traffic information via radar displays on the ground. However in the future, pilots would have the means to see what is around them based on Aircraft Surveillance Applications System (ASAS), which will help pilots to better understand the surroundings of the aircraft. By applying ASAS, the way to control air traffic makes a shift to a distributed control based on each pilot' s decision, instead of a centralized control which is currently done by air traffic controllers. This paper introduces our ASAS studies and the state-of-the-art of evaluating the mixture of the distributed and centralized control in the future ATM system.
【要素的】 特集 28巻3号(2014)  群衆; セルオートマトン; 数値計算;
Pedestrian dynamics, which has been vigorously studied in traffic engineering, architecture and psychology, also started to attract interest of physicists in the end of the twentieth century. It is almost impossible to predict the movement of an individual pedestrian in detail since she has own will. Physicists, however, have elucidated the macroscopic collective behaviors of pedestrians by dealing them as “self-driven” particles whose destination is clear. In this paper, the author introduces the research on three fundamental pedestrian dynamics, i.e., unidirectional flow, bidirectional flow and egress process, with analysis of cellular automaton models. In congested unidirectional flow, slow rhythm improves pedestrian flow. In bidirectional flow, appropriate anticipation smooth the flow, while excessive anticipation hinders it. Furthermore, in egress process, an obstacle increases the flow if it is set at proper position.
【巨視的】 特集 28巻4号(2014)  粒子; 圧力損失; スラリー;
JGC has been developing a simulation method to predict solid deposition and pressure drop of slurry flows in pipelines with a shortened computation time. In this article, some case studies for validation of simulation methods by comparing the results of simulation with those of experiments are described. In addition, we have pointed out some considerations for the CFD simulation of slurry behavior.