Closed-loop fueling control of a dual-mode scramjet was successfully
demonstrated using optical emission spectroscopy as the sole sensor
for controller feedback. The optical emission from species of interest (OH∗, CH∗, C2∗) was first characterized throughout
the combustor. The relative emission intensity between species pairs
was studied over a range of fueling conditions and imaging locations
throughout a dual-mode scramjet combustor flow path. The pair of
emissive species (C2∗/OH∗) and imaging location that were the
most sensitive to changes in fueling condition were selected for use
in the control system. Changes in optical transmission of the
observation windows and the impact on fuel control were explored. To
our knowledge, this paper is the first demonstration of fueling
control of a dual-mode scramjet using only optical emission
spectroscopy as feedback.