2003 Fiscal Year Final Research Report Summary
A Study on Improvement of Performance of Ship Propulsion Device Directly Driven by Steam
| Project/Area Number |
13450077
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Kobe University |
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Principal Investigator |
TSUTAHARA Michihisa Kobe University, Graduate School of Science and Technology, Professor, 自然科学研究科, 教授 (10031139)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAMOTO Masahiko Nara National College of Technology, Associate Professor, 助教授 (00225822)
KATAOKA Takeshi Kobe University, Graduate School of Science and Technology, Research Associate, 自然科学研究科, 助手 (20273758)
OGAWA Kazuhiko Kobe University, Department of Engineering, Associate Professor, 工学部, 助教授 (30252802)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Shin propulsion device / Flow inside nozzle / Unsteady flow / Air-water two-phase flow / Flow visualization |
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| Research Abstract |
By visualizing the flow inside the nozzle by high-speed video camera, it is shown that the flow is not a mixed flow of air and water but a flow in which the air and the water are separated and waves with large amplitude appear on the interface. These waves close the air flow and the pressure rises and the pressure accelerate the water, towards downstream. It is also shown that the mechanism in accelerating the water is not mixing but the volume of water accelerated by air pressure without mixing. So the loss is smaller than the mixing mechanism. The case of intermittent emission, the thrust itself does not increase, but the propulsive efficiency considering the emission duration, the operation of intermittent emission is better.
The numerical simulation by the finite difference lattice Boltzmann model for two fluids gives good results. On the interface between the two fluids, large-amplitude waves appear. But in this model the densities of the two fluids are the same, then we tried to improved the two-fluid model. The density difference corresponds to the acceleration difference, so by modifying the acceleration the density difference can be simulated. For single-phase flows, this technique is shown to be successful. A new model with choosing specific heats for multi-atomic gas is also introduced.
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