Jet Force Field Keeps Air Flowing Over Wings
You could call the device still being developed by GE an air jet force field. But instead of deflecting alien lasers, this technology’s aim is to keep air moving efficiently over wings and turbine blades.
GE engineers are working on the technology, which uses puffs of air to virtually change the shape of a wing or turbine blade. The result—less friction and turbulence on the flight surface—shaves fuel use from airplanes and improves a turbine’s ability to convert wind into electricity.
In the high-performance worlds of commercial jets and wind turbines, squeezing out a few percentage points of efficiency can make a major difference.
GE Global Research scientists are developing devices that use tiny amounts of energy and no moving parts to breathe in and pump air jets through small holes along a wing or blade’s surface. The innovations, called synthetic jet actuators (SJAs), speed up air that naturally slows as it flows over the surface due to friction.
“By expanding and contracting a chamber such that air is sucked in and ejected through a single hole, this device works similar to a human lung,” says Seyed Saddoughi, Principal Engineer in Aero-Thermal & Mechanical Systems, who is leading the actuator’s development. “The advantage is that there is no need for pumps that use external flow, or fans with moving parts. The device is lightweight and very simple in operation, with minimal power usage.”
SJAs pump air efficiently by applying an alternating current to two parallel plates separated by a slight space. Employing a phenomenon called the piezoelectric effect, the two plates bend and straighten as electricity moves through them, causing the middle chamber to rapidly pull in and push out air.
Because of its paltry energy use, powerful air jet and silent operation, a version of the device as thin as a credit card is already beginning to be used for a very different application. A major manufacturer of cooling devices for electronics has licensed the technology for use in consumer electronics and computers.
But Saddoughi says SJAs will realize their potential when rows of them start getting embedded in the wings of jets and turbine blades. His research team has also been experimenting on another version that can operate in water. Their experiments have shown that pumping high-powered water jets against the surface of boat hulls can change hydrodynamic flow and decrease drag.
“These devices energize the flow close to surfaces to reduce losses and increase the overall efficiency of the machines,” he says. “Synthetic jet actuators give us active control of flow over these surfaces. We can manipulate flow intelligently to gain better performance from our machines.”