Numerical Investigation of Influence of Quasi-DC Discharge Plasma on Fuel Jet in Scramjet Combustor

A plasma filament is generated upstream of the fuel jet through quasi-dc discharge in a scramjet combustor. The effects of the plasma filament on fuel mixing and combustion are numerically investigated based on the dominant thermal blocking mechanism. Results have shown that temperature distribution of the whole flowfield is changed prominently due to heat release from the plasma filament. Since the shock waves induced by the transverse fuel jet are partly weakened and move upstream by the plasma filament, the separation zone upstream of the fuel orifice can be controlled to provide a better combustion environment. Compared with the no-plasma case, more water appears in higher space above the bottom wall while less near the bottom wall of combustor. Although the stagnation pressure loss increases a little owing to the plasma filament, the combustion efficiency rises obviously with only a little external energy addition.