| Project/Area Number |
11650175
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | Osaka University |
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Principal Investigator |
TANAKA Toshitsugu Osaka University, Graduate School of Engineering, Assoc.Professor, 大学院・工学研究科, 助教授 (90171777)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAGUCHI Toshihiro Osaka University, Graduate School of Engineering, Research Assoc., 大学院・工学研究科, 助手 (80234045)
TSUJI Yutaka Osaka University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (10029233)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1999: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Keywords | Multiphase Flow / Gas-Solid Flow / Meso-Scale Structure / Particle Cluster / Numerical Simulation / Experiment / 固気ニ相流 / 数値シミュレーション |
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| Research Abstract |
Gas-solid flows with particle clusters were studied. Numerical simulations were performed for the gas-solid flows in a rectangular-parallelepiped calculation domain surrounded by periodic bound-aries. Fluid motion was calculated by using DNS and LES, in which the same SGS model as in single-phase flows was assumed. Solid flow was calculated by the Lagrangian method, in which the motion of individual particles was tracked, with considering particle-particle collisions. Furthermore, an experiment on the granular sedimenting flows in a vertical duct was performed to measure the structure of particle clusters and to validate the present simulation. The results are summarized as follows.
1. The present LES and DNS predicted the formation of particle clusters. Effects of mean solid- volume fraction (SVF) and fluid viscosity on the flow structure were examined. It was found that, in the case of mean SVF of 10^<-5>, the formation of particle clusters was observed, but it takes much longer time
… More
than the higher fraction cases. The spatial scale of particle clusters decreased with increasing the fluid viscosity. We examined the smallest eddy scale in the present simulation results and found that DNS had performed for the present calculation conditions.
2. It was found that the fully developed flows were established in the lower region of the duct. The structure of particle clusters in vertical and horizontal planes were observed by using laser-sheet visualization technique. The structure of clusters observed is like a network of strands and similar to both of the present numerical predictions and previous experiments in risers of CFB.Distributions of the solid volume fraction in the duct cross-section was measured. It was found that particles tend to concentrate to duct walls and this tendency is enhanced in high solid flow rate.
3. The measured fluctuation pattern of the local SVF is similar to the present predictions. The profile of probability density function of the measured SVF agrees well with the predictions. Power spectrum of fluctuation of the measured SVF agrees qualitatively with the predictions, but quantitatively, fairly well. Less
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