1998 Fiscal Year Final Research Report Summary
Analysis and Modeling of Transport Phenomena in a Complex Multiphase Flow by High Resolution Opt-electrical Measurements
| Project/Area Number |
08405019
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | Keio University |
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Principal Investigator |
MAEDA Masanobu Keio University., Faculty of Science and Technology, Professor, 理工学部, 教授 (90051466)
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| Co-Investigator(Kenkyū-buntansha) |
HISHIDA Koichi Keio University, Faculty of Science and Technology, Professor, 理工学部, 教授 (40156592)
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| Project Period (FY) |
1996 – 1998
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| Keywords | Laser technique / Non-intrusive measurement / Velocity measurement / Shape measurement / Non-sphetical particle / LDV / PDA |
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| Research Abstract |
Focusing on the clarification of the complex mechanism of transport processes in multiphase flows, a series of analytical and experimental investigations has been carried out concerning numerical prediction with a new type of turbulence models, i. e. , multiple scale for dispersed multiphase flows, the concerned development in instrumentation of high resolution sensing system by laser technique, and a signal processing system using on-line computing network.
Basic development of instrumentation has been performed by a combined technique such as flow and temperature or concentration field measurements. A laser Doppler technique was extended to capture the particle shape using Shadow Imaging ; We called the technique as "SHADOW DOPPLER VELOCIMETRY". The Shadow Doppler method was applied to the flow filed in confined jet where non-spherical particle dispersed more than spherical particles due to their larger lift force caused by particle orientation.
For the measurements of bubble flows, hi
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gh-speed digital camera was employed for the evaluation analysis with higher time resolution. Experiments have been conducted on bubble deformation and behavior in shear layer. The flow structure in the vicinity of the bubble boundary was analyzed by Digital particle image velocimetry supplemented the laser induced fluorescence particle and instantaneous shape by infrared Shadow Image Techniques. It was pointed out that the bubble-induced turbulence is primarily determined by bubble wobbling and stretch itself by the induced vorticity in the wake.
The Streo-Paricle Image Velocimetry was developed to measure the third velocity component in the flow field, which was tested in a two-dimensional oblique jet evaluating the measurement error in the direction to the depth.
From these experimental results, an adequate modeling has been done by combining the multiple time scaling for turbulent multiphase flows. Also, the direct numerical simulation on homogenous two-phase turbulent flow showed the fundamental structure of energy transfer between particle and fluid. Less
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