Study on Flame Acceleration Phenomena at Gas Explosions
| Project/Area Number |
60490005
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
広領域
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| Research Institution | The University of Tokyo |
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Principal Investigator |
HIRANO Toshisuke Faculty of Enginering, the University of Tokyo, 工学部, 教授 (70007615)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥5,600,000 (Direct Cost: ¥5,600,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | Gas explosion / Flame acceleration / Turbulent premixed flame / Turbulence amplification mechanisms / 火炎伝ぱ / 非定常火炎 |
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| Research Abstract |
The turbulence growth at flame fronts far from solid walls, which has remained ambiguous in spite of its importance for understanding overall flame acceleration at gas explosions, has been studied and the following results have been obtained.
1. Two types of flame propagation test apparatus were designed to induce a shear flow near a propagating flame front and velocity change in the direction normal to the flame front. By using these apparatus, turbulence at a propagating flame front was caused, and its variation was recorded by high speed schlieren photography and examined. At the same time, the pressure fluctuation in the combustion chamber is recorded.
2. The obtained high-speed schlieren photographs were analyzed using film analyzer and computer, and comparing the result to the pressure record, a close relation was found between the flame acceleration or deceleration and pressure fluctuation.
3. By examining the motions of turbulent premixed flames under various conditions, it was revealed that the flame front turbulence depends largely on the neighboring flow field. In the flow field for flame acceleration, very rapid development of flame front turbulence was observed, while in the flow field for flame retardation, flame front turbulence was observed to be suppressed and its scale became small. These results coincide well with those of a computer simulation.
4. The pressure-time diagrams were predicted by considering the effects of flame acceleration on pressure increase in gas explosions. The results indicate that the pressure-time diagrams become close to those at actual gas explosions by considering the turbulence growth and that turbulence growth increases the maximum pressure and reduces the time to it.
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Report
(1 results)
Research Products
(6 results)
