Towards Closed-Loop Control of Unstart in Scramjets: Development of Tools for Optimal Design of Sensors and Actuators

ABSTRACT:The objective of this program proposed by Spectral Energies, LLC and University of Texas at Austin is to develop a novel framework for optimal design of sensors and actuators for use in closed-loop control of dual-mode scramjet engines. In Phase I, the framework was developed by analyzing new measurements of unstart in Mach 2 inlet-isolator, which could be perturbed by a downstream flap and/or upstream pulsed air jets. A new algorithm (CUSUM) was developed, which enables superior detection of shock propagation using pressure data. Furthermore, system identification of the Mach 2 data revealed that linear dynamic models were largely inadequate in representing the dynamics. In contrast, nonlinear models performed well for predicting data for large variations in flap angle and jet pulsing frequency. In Phase II, a new wind tunnel model will be used that enables improved control of the boundary layer, more robust control schemes and a broader range of sensors to be applied. The Phase II analysis will develop a more robust framework that is validated under a wider range of conditions, with different sensors and actuators, and under non-reacting and reacting flow conditions. The framework will also be applied to achieve closed-loop control of unstart under both cold and reacting conditions.BENEFIT:The proposed research effort will make significant progress toward achieving critically needed sensor and actuator performance characterization data to enable the robust design of active control systems for scramjet engines. Military and commercial applications include but not limited to space launch vehicles, time-critical weapon systems, strike/reconnaissance vehicles, and systems related to space access.