• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.1
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• pp.28-35
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• 2018

In order to analyze the flammability limit and structure of the gaseous methane-gaseous oxygen diffusion flame formed through a shear coaxial injector, combustion experiments were carried out according to the condition of injector recess and propellant mass-flow rate. As a result, it was confirmed that stable anchored flame was observed even at the high oxygen Reynolds number as the propellant momentum flux ratio increased, and that the recess had no significant influence on the flame shape and flammability limit. The anchored flame visualized through a chemiluminescence showed the maximum OH radical emission intensity at a specific position, irrespective of the propellant injection condition, and the radical intensity was greatly reduced by the injector recess.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.4
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• pp.506-513
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• 2008

The engine containing a radical injector has been studied to improve the performances of efficiency and to reduce the exhaust emissions recently. The engine is far different from general compression ignition engines or spark ignition engines for the concept of combustion process. The inflow characteristic from main chamber into radical chamber during compression stroke is important because the radical chamber must have enough fresh air to generate appropriate radicals. The numerical simulation is performed in each specific shape and the engine speed by using KIVA code. The result shows that the fresh air inflow from main chamber into the radical chamber is the best at 45 degree of the hole angle.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.1
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• pp.1-8
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• 2019

To analyze the dynamic behavior and the structure of the gaseous methane-gaseous oxygen diffusion flame formed by a swirl/shear-coaxial injector, combustion experiments were carried out under different propellant injection conditions. As a result, the OH radical emission intensity of the diffusion flame visualized through chemiluminescence was observed to increase as the propellant mass flow and the momentum flux ratio increased. And flames with swirl showed a more high radical emission intensity than those without swirl.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.9
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• pp.1309-1316
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• 2003

A premixed-compression-ignition engine has been studied to improve the efficiency and to decrease exhaust emissions. However those systems have some difficulties for controlling combustion process. Radical is an activated chemical species formed by a chemical chain reaction between reactant and product. When the chain reactions occur, the energy bond of species is broken easily by the released radicals. The combustion chamber of the premixed-compression-ingnition engine is consist of a main chamber with lean premixture and a subchamber with rich premixture. Those are connected by narrow cylinderical connections. With ignition start in the subchamber, many different kinds of radical is jetted into the main chamber. The premixed gas in main chamber is quickly burned up by the radical ignition in multi-pionts. In this paper, the combustion phenomena in a constant volume combustor having a radical injector are numerically analyzed. The some constants in the reaction rate equation are adjusted by the experimental results tested in the same geometrical chamber. The code is applied on the two combustors in a wide range of equivalence ratio. The results show that the burning time is much shorter in the combustor having radical injector.