Research On The Flame Holding Technology Based On Cavity In Supersonic Combustion

The flame holding technology based on cavity in supersonic combustion was studied systematically and comprehensively.The interaction between gas/liquid injection and cavity flow were studied in non-reaction flows. Results indicate that the characteristics of cavity flowfield were altered similarly by gas and liquid injection. The local boundary layer or shear layer are modified by injection on upstream/bottom wall of cavity, and the cavity shear layer immediately becomes angled with respect to the main flow direction. The injection on fore wall of cavity has little effect on the characteristics of cavity flowfield.The combustion and flow process of cavity flame holder with liquid kerosene fuel on room temperature were investigated experimentally, with different fuel equivalence ratio and injection schemes. It is found that the liquid kerosene of injection upstream cavity could finish the process of atomization and evaporation in short distance, and enter into cavity through convection. Aft wall is the primarily area of flame holding in cavity, and the only area when near the lean blowout limit, flame in area of fore wall are spread from it. Cavity shear layer in reaction flow angle greatly to the main flow direction, and couldn't reattach to aft wall anymore, it appears great difference in characteristics of cavity flowfield between non-reaction and reaction state.Experiments on the lean blowout limit of cavity flame holder with liquid kerosene fuel on room temperature were conducted with various cavities and injection schemes. The result indicates that the range of stable lean operation varies greatly for different cavity depth D and length-depth-ratio L/D, it increases with increasing D and L/D, and increases, followed by decreasing with increasing incline angle of aft wall. Adding injection on bottom or fore wall of cavity, based on chief injections on upstream, provides worse lean flameholding performance.Experiments on the drag of cavity flame holder were conducted by force measurement system. The result of investigation on drags of cavities under combustion condition, with different injection schemes and fuel equivalence ratio, indicates that it is smaller than it's of cold flow, and decreases with increasing fuel equivalence ratio, and could be converted into the...