摘要 :
National Institute for Resources and Environment has been carrying out a basic study of a lifting system of manganese nodule. The objective of this paper is to summarize results on vertical transportation of manganese by a large-s...
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National Institute for Resources and Environment has been carrying out a basic study of a lifting system of manganese nodule. The objective of this paper is to summarize results on vertical transportation of manganese by a large-scale air-lift pump. First, the authors discuss procedure and scheme to design a large-scale air-lift pump for large particles such as manganese nodule. Second, experimental results on pump performance of 200m air-lift pump (151mm in pipe diameter and 212.6m in pipe length), which is designed on the basis of the procedure developed by NIRE, are described. Analytical results are compared with the experimental results to find that the procedure and the scheme are reasonable. Third, similarity of air-lift pump characteristics such as flow pattern, static pressure and hold-up will be discussed. Finally, numerical scheme to simulate unsteady pump characteristics of large-scale air-lift pump is proposed.
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摘要 :
National Institute for Resources and Environment has been carrying out a basic study of a lifting system of manganese nodule. The objective of this paper is to summarize results on vertical transportation of manganese by a large-s...
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National Institute for Resources and Environment has been carrying out a basic study of a lifting system of manganese nodule. The objective of this paper is to summarize results on vertical transportation of manganese by a large-scale air-lift pump. First, the authors discuss procedure and scheme to design a large-scale air-lift pump for large particles such as manganese nodule. Second, experimental results on pump performance of 200m air-lift pump (151mm in pipe diameter and 212.6m in pipe length), which is designed on the basis of the procedure developed by NIRE, are described. Analytical results are compared with the experimental results to find that the procedure and the scheme are reasonable. Third, similarity of air-lift pump characteristics such as flow pattern, static pressure and hold-up will be discussed. Finally, numerical scheme to simulate unsteady pump characteristics of large-scale air-lift pump is proposed.
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摘要 :
Ocean sequestration of CO_2 is a hopeful option to solve the global warming problems. We proposed the Gas Lift Advanced Dissolution (GLAD) System for efficient sequestration of pure CO_2 at deep sea. The GLAD system is an inverse-...
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Ocean sequestration of CO_2 is a hopeful option to solve the global warming problems. We proposed the Gas Lift Advanced Dissolution (GLAD) System for efficient sequestration of pure CO_2 at deep sea. The GLAD system is an inverse-J pipeline set in the ocean between 200 and 3000 m in depth. We have recently improved it to treat low-purity CO_2 gas to reduce the cost for separation and capture of CO_2 from exhausted gas.
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A direct numerical simulation (DNS) of turbulent round jet was carried out in the cylindrical coordinate system to provide a tool for a numerical experiment for jet control. The spatial development from the formation of vortex rin...
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A direct numerical simulation (DNS) of turbulent round jet was carried out in the cylindrical coordinate system to provide a tool for a numerical experiment for jet control. The spatial development from the formation of vortex rings to the transition to turbulence was accurately obtained by a finite-difference method. The characteristics of simulated flow field, such as vortex rings and self-similar profile of mean flow in turbulent region, is in good agreement with experimen- tal findings. Insufficiency of the computational domain in the radial direction leads the flow field to turbulence earlier. The influence of superposition of coherent disturbances to random perturbation at the nozzle exit, e. g. axial and helical ones, has also been investigated. The perturbation mode strongly affected the configuration, strength and location of vortices and their turbulence transition. The delay in turbulence transition, especially by axial excitation, was due to the maintenance of the strong vortices. Such a structure was clearly detected by the proper orthogonal decomposition (POD) method.
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摘要 :
The mechanism of three-dimensional rotational flow in a curved duct caused by distorted inflow is investigated numerically. The steady, laminar flow of viscous, incompressible fluid in a 90-deg. curved duct with a square cross sec...
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The mechanism of three-dimensional rotational flow in a curved duct caused by distorted inflow is investigated numerically. The steady, laminar flow of viscous, incompressible fluid in a 90-deg. curved duct with a square cross section is simulated by the pseudo-compressibility method. A uniform velocity gradient is assumed at the entrance of the computational domain.
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A full three-dimensional simulations by means of a finite difference method of incompressible near-stall flows in a stationary straight cascade of blades is presented in this report. The aim of the work is to compare the flow with...
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A full three-dimensional simulations by means of a finite difference method of incompressible near-stall flows in a stationary straight cascade of blades is presented in this report. The aim of the work is to compare the flow with those in a rotating cascade which is described in the accompanying paper. Two cascades are nearly identical in geometry with respect to inlet flow condition, namely, same attack angle which is uniform in spanwise direction and also to flow in tip clearance.
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The patterns of secondary flows in a curved duct depend on many factors such as Dean number, the geometry of the cross section and the inflow velocity profile. The prediction of frictional loss in the pipeline system, therefore, i...
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The patterns of secondary flows in a curved duct depend on many factors such as Dean number, the geometry of the cross section and the inflow velocity profile. The prediction of frictional loss in the pipeline system, therefore, is difficult. In this study, the viscous flow of incompressible fluid in a 90°curved duct of rectangular cross sections is numerically simulated by the pseudocompressibility method. The influences of the aspect ratio of the cross section and the distortion rate of inlet flow on the frictional loss are investigated. °
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