Model-Free Control System for Scramjet Applications

Flow fluctuations in the flame-holder cavity affect its stable operation that can lead to degradation of its performance. Efficient cavity operations can be enhanced through active control of injection of air and fuel mixtures. We propose to design and validate a novel Model-Free Direct (feedback) Control system to ensure stable cavity operation in the subsonic regime with smooth transitions to supersonic combustion. We will focus on a model-free strategy interacting with sensor and actuator arrays. Control system design and prototyping will be done with the aid of an existing simulation environment that connects flow solvers acting as plant emulators to control software. This approach will allow full accounting of the interaction of sensor-controller-actuator-flow dynamics in an active flow control loop.  Phase I will focus sensor-controller-actuator model preparation, design of numerical experiments for control system testing, and simulation of combustor operations for testing of control system performance. The testing will involve control software-in-the-loop and control hardware-in-the-loop simulations. The response of flowfield to variations in the sensor-controller-actuator configurations will be evaluated.  Phase II work will oversee the refinement of the existing control hardware prototype.  Phase III commercialization will seek to exploit the natural dual-use applicability of the developed hardware. BENEFIT: In addition to military use, the generality of the controller design will be suitable for multi-use applications. Immediate use relates to optimization of flame-holder operations, and prevention of isolator unstart in scramjet combustors. It will also benefit areas where distributed flow control is of interest including: aerospace (L/D and maneuverability optimization), maritime (wake signature minimization), and automotive (combustion efficiency maximization). Controller hardware will be interfaceable with personal computers using low-cost PCI boards. Such an interface will allow for very efficient virtual prototyping of complete control systems.