| Co-Investigator(Kenkyū-buntansha) |
KAWANO Hideaki Kyushu University, Faculty of Engineering, Research Associate, 工学部, 助手 (30037915)
HANADA Kunihiko Kyushu University, Faculty of Engineering, Research Associate, 工学部, 助手 (30037874)
MURASE Eiichi Kyushu University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (60150504)
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| Research Abstract |
As a scheme for combustion control in a swirling flow of the spark ignition engine through flame growing process, the flame behaviors which is actively controlled by the convective motion of flame and the flame initiation processes, are examined in the solid vortex model. The observed behaviors of flames initiated by 1)spark ignition at the off-centered position in a swirl, 2)using of the plasma jet igniter, 3)multi-spark ignition, illuminate how the flame growing process in the centrifugal force field depends on the flame initiation method. When a flame is initiated at the vessel center, the enhanced combustion by the swirl cannot always be realized but a decay in propagation rate appears by the lamminarization of flame front and a disturbance on the flame due to a difference in rotation speed between the unburned and the burned zone. Even if the ignition is made at the off-center position, a reduction of flame area by the wall quenching and accordingly, the increased heat loss can be avoided by the flame convection. However, too fast convection results in the earlier arrival of flame at the center, and a flame with small radius may easily be disturbed in the successive process. The flame ignited by the weak plasma jet also suffers the disturbed propagation as well as the spark ignited flame. With the increased turbulence by the powerful jet, the burning rate in the earlier stage is improved with increase of omega, but the delayd propagation soon appears in the course of the process. The single flame, whether initiated by the single spark or the plasma jet, is apt to grow the center-symmetrical flame to cause the delayd combustion. The holding of flame around ignition source results in the enhanced combustion by extending the flame area to the down stream region. When several flames can be successively initiated at a fixed ignition plug by carrying away the flame kernel with swirling flow, the rate of heat liberation may be controllable by alterling the initiation
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