SBIR-STTR Award

Combustion powered actuation (COMPACT) technology was developed at Georgia Tech for high-speed flow control applications. COMPACT produces a pulsed jet by the ignition of a mixture of fuel and oxidizer in a miniature (cm3-scale) combustion chamber. The combustion creates a rapid pressure rise in the chamber and the subsequent ejection of a high-speed jet through a single or multiple orifices. Chamber pressures up to 5 atm have been achieved in prototype devices and yielded sonic orifice velocities and high jet momentum coefficients suitable for aerodynamic flow control (shock control, separation, drag reduction, etc.) at transonic or supersonic speeds. Reactants flow into the chamber is regulated by passive fluidic valves such that COMPACT operates without moving parts and presents minimal infrastructure requirements. Liquid fuel COMPACT arrays that are batch-fabricated, lightweight, with integrated plumbing and electronics can be realized and are the focus of the proposed STTR research. The proposed work will characterize and optimize the performance of COMPACT actuators that are driven by liquid fuel (using atomization or fuel reforming) and will include the development of high-volume MEMS-based batch fabrication approaches. COMPACT performance will be demonstrated in two transonic wind tunnel tests to be performed by the Boeing Company.

Benefits:
The ability of combustion-powered actuators (COMPACT) to control aerodynamic flows at transonic and supersonic speeds has the potential to dramatically alter the flight envelope of commercial and military aircraft. It is envisioned that the first application of COMPACT to flight platforms will be demonstrated by Boeing in transonic wind tunnel test of drag reduction with potential future implementation in high-speed, high-maneuverability transonic aircraft. It is anticipated that the total fuel (same as for engines) consumption by COMPACT actuation will be very low compared to other energy expenditures during flight. Initially discrete COMPACT arrays will be used to augment conventional control surfaces, and later designs may become fully distributed to optimize control authority over the entire wing potentially replacing conventional control surfaces. It is likely that initial flight demonstration will take place on UAV-class aircraft and once reliability is proven, adoption would next occur in manned military aircraft. Eventually, this mode of actuation may find use on commercial aircraft. The ultimate vision of the company is to develop and commercialize jet actuators that are more efficient and cost-effective than conventional control surfaces. Commercialization of the technology will proceed down two paths. The first path will involve selling COMPACT devices to researchers in the fluid mechanics, aerodynamics, and MEMS scientific communities. A large market exists for small, high-control-authority actuators for a variety of scientific experiments; e.g., aerodynamic control on lifting surfaces, control of internal flows in ducts, fluidic-based mechanical actuation (e.g., exoskeletons and robotics), etc. The second path will build on the substantial interest that The Boeing Company has shown in implementing this actuation technology in military and commercial platforms. Abstract: flow control, combustion, actuators, flight control, transonic, control surfaces, COMPACT

Combustion powered actuation (COMPACT) is a flow control technology developed at Georgia Tech which utilizes a miniature combustion chamber (cubic centimeter scale) to produce high-speed pulsed jets suitable for aerodynamic flow control (separation control, drag reduction, shock control, etc.) at transonic or supersonic speeds. The system is lightweight, can be operated with passive fluidic valves (such that the actuator has no moving parts), and creates actuator jets with momentum far beyond other current actuation approaches. The proposed STTR Phase II program will continue the development of an optimized actuator system which can be mass-manufactured with integrated chamber formation, plumbing, and electronics, can operate from a liquid fuel source, and has proven effectiveness in manipulating high-speed flows. The work program will build towards this objective with four task groups: actuator development (including in-depth analysis and optimization of the combustion and chamber refill processes and actuator endurance testing), liquid fuels adaptation (featuring parallel development of systems utilizing atomization, fuel reforming, and pressurized liquid fuels), batch fabrication of actuators (furthering metal laminate techniques developed during Phase I, prototyping unique actuator configurations for improved performance, and developing integrated electronics), and high-speed flow control demonstrations (including a test at the facilities of The Boeing Company).

Keywords:
ACTIVE FLOW CONTROL, COMBUSTION-BASED ACTUATOR, COMPACT, HIGH-SPEED FLOW CONTROL, HIGH POWER ACTUATO