Effect of Hydrogen Jet Position Relative to Plasma Torch on Supersonic Combustion

Abstract

ABSTRUCT The purposes of the present study were to clarify the three-dimensional structure of hydrogen flame reinforced by a plasma torch and to analyze the effect of the position of a hydrogen jet relative to the plasma torch on the combustion characteristics. Results of the present analysis clarify that the combustion efficiency of hydrogen jet injection into the upper stream of the plasma torch becomes larger than that of hydrogen jet injection into the lower stream. When the hydrogen jet is injected into the lower stream of the plasma torch, the combustion efficiency is reduced with the increase of the interval between the plasma torch and the hydrogen jet. In addition, as the interval decreases, an extension of the recirculation zone, which causes a significant increase of combustion efficiency, is observed. On the other hand, when the hydrogen jet is injected into the upper stream of the plasma torch, a larger interval generally results in larger combustion efficiency. When the plasma torch is injected with high injection pressure, penetration of the plasma torch is extended and mixing of hydrogen and air is significantly improved, resulting in higher combustion efficiency.