Scramjet Unblocker -

Unstart typically originates from thermal choking: excessive heat release from combustion raises the static temperature, reducing the Mach number in the combustor below unity. A normal shock wave then propagates upstream through the isolator, causing massive spillage and drag.

| Parameter | Value | |--------------------------|--------------| | Freestream Mach number | 6.0 | | Inlet capture height | 0.15 m | | Combustor length | 0.8 m | | Equivalence ratio (nom.) | 0.9 | | Unblocker slot width | 2 mm | scramjet unblocker

The current design assumes a single unstart event per flight. Repeated cycling may lead to fatigue of the hatch mechanism. Furthermore, the plasma actuator's power draw (≈1 kW) may be prohibitive for small-scale scramjets. Repeated cycling may lead to fatigue of the hatch mechanism

This research was supported by the Hypersonic Air-breathing Propulsion Consortium (HAPC). [1] Curran, E

[1] Curran, E. T. (2001). Scramjet engines: the first forty years. Journal of Propulsion and Power , 17(6), 1138-1148. [2] Matsuo, K., et al. (2009). Unstart phenomena in scramjet inlets. Progress in Aerospace Sciences , 45(8), 285-310. [3] Do, H., et al. (2011). Plasma-assisted flame stabilization in a scramjet. Combustion and Flame , 158(4), 755-763. [4] Reed, A. J. (2024). Fast-acting bleed systems for hypersonic inlet control. AIAA Journal , 62(1), 112-125.