CFD Research Corporation has developed a low frequency, high amplitude fuel actuator. The actuator is designed to allow control over the amplitude (near zero to full on/off) of the fluid pressure modulation at frequencies below 100 Hz, and is scalable to meet a broad range of application requirements. Significant reductions in both size and weight have been achieved. Actuator mass was reduced by a factor of 11 and volume was reduced by a factor of 8 over the best commercially available technology with the same output power. The newly developed actuator is based on robust and proven electromagnetic technology. The final prototype has been tested for durability, with over 100 hours of continuous operation at the maximum power setting with no degradation in performance measured.

One application for the new technology is active control of combustion instabilities through fuel modulation. Fluid flow modulation has been demonstrated to be an effective technique for the control of acoustic instabilities in gas turbine combustors and augmentors in the 100 to 800 Hz range. Flow modulation can also be used to improve atomization of liquid sprays for combustion and other applications. Another potential use for the actuator is fuel flow control in pulsed combustion systems.

The advanced capability offered by this magnetic actuating device is in contrast to the high frequency (> 10,000 Hz), low amplitude fuel modulation of existing piezoelectric actuators. The actuator currently in use has demonstrated some of the positive effects of fuel modulation on gas turbine combustors, but its size is too large to be practical and is impossible for aero engine applications. One of the main goals of this project is to develop an actuator that provides the same power output as the current actuator (4lb), but at 1/10th the weight and volume. The current actuator is approximately 3.0 inches in diameter, and 3.5 inches in length. This reduction will require the use of rare-earth metals such as SmCo. CEB has recently acquired the services of Corcoran Engineering experienced in magnetic circuits and electromagnetic devices. Corcoran Engineering will perform all of the necessary electrical design work.

CFDRC has the necessary expertise to adapt and further develop fuel actuators for specific applications.