Experimental Investigation on Pressure and Flame Surface Oscillation in a Dual-Cavity Scramjet Combustor

Abstract

Pressure and flame surface oscillations are common in supersonic combustion instability. Understanding the characteristics, generation, maintenance, and interaction mechanisms of these oscillations is crucial. An experimental setup with an alcohol heater was used to study injection positions and fuel quantities in a dual-cavity scramjet combustion chamber. High-frequency pressure sensors and high-speed equipment were employed in this research. The most significant pressure oscillation occurred at a global equivalence ratio of 1.2 with a frequency of 300 Hz and an amplitude of 43%. Mean oscillation was not affected by changes in equivalence ratio. Increased amplitude was linked to stronger flow instability, indicating that flow instability induced by unstable heat release plays a significant role in supersonic combustion instability.

Keywords

• supersonic combustion instability
• nonlinear dynamics
• scramjet combustors