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. Creare and its partners propose to develop passive optical combustion sensors for closed-loop control of scramjet engines. These sensors are high frequency and rugged, and they will be easy to integrate with flight engines. In Phase I, we demonstrated the ability of these sensors to provide useful data for engine control and combustor R & D. In Phase II, we will optimize the sensors for scramjet conditions, apply them to high fidelity combustors, and determine how to use the signals for closed-loop engine control. BENEFIT: Technology derived from this program will be in the form of high-frequency passive optical sensors optimized for scramjet conditions and methods for using them in closed-loop engine control schemes. These sensors and control schemes will enable optimal performance of scramjet engines over a larger flight envelope. This sensor technology could also be used for combustion control in augmentors to enhance flame stability or industrial furnaces to reduce harmful emissions.