Passive Optical Combustion Sensors for Scramjet Engine Control

ABSTRACT: Dual-mode scramjet engines must operate over a wide range of flight Mach numbers. Closed loop engine control is necessary to maintain thrust and flame stability while preventing unstart over the large flight envelope. High-frequency sensors and actuators will be a key component of future scramjet Full Authority Digital Engine Controllers (FADECs) due to the short time scales associated with these engines. These sensors and actuators must be rugged, simple, lightweight, low power, and minimally intrusive. In the proposed effort, Creare and the University of Michigan will develop passive optical heat release and equivalence ratio sensors and control schemes which utilize them for closed loop scramjet engine control. These sensors are high frequency and rugged and will be easy to integrate with flight engines. In Phase I, we will build and test these sensors in a laboratory scramjet combustor and determine how the signals could be used to predict unstart and maintain flame stability for some key engine transients. In Phase II, we will optimize the sensors for scramjet conditions and develop and test active control schemes for preventing unstart and maintaining flame stability using the sensor input. BENEFIT: Technology derived from this program will be in the form of high-frequency passive optical sensors optimized for scramjet conditions and closed loop engine control schemes which utilize these sensors for feedback. These sensors and control schemes will enable optimal performance of scramjet engines over a larger flight envelope.