Rahul Patel

Rahul Patel

Aerospace Engineering MEng

Double Chamber Synthetic Jet Actuator for Reduced Noise Output

The main application for a synthetic jet actuator is to be implemented, in series, near the trailing edge of an aircraft wing, in order to delay flow separation and enhance lift. The actuator mainly relates to the Aerospace Engineering field. It was important to do this study in order to find out methods in which the noise output from the standard synthetic jet actuator can be greatly reduced and the power efficiency can be increased. This project investigates comparing the performance of a double chamber synthetic jet actuator to a single chamber synthetic jet actuator in terms of the velocity and noise produced and the power efficiency of each. A synthetic jet is a form of pulse jet of fluid produced from the periodic motion of a diaphragm mounted in a cavity with an orifice on one or more walls. A synthetic jet actuator produces really high pitch noise output and has a low efficiency, so therefore this project looks into the ways of improving these factors. These are the two main factors limiting its use on an aircraft wing to enhance lift during the critical stage of the flight envelope. A synthetic jet actuator, with interchangeable configurations, was designed, manufactured and tested. From the results it was concluded that the actuator operating as a double chamber configuration reduces noise output up to 30 dB, due to its operation in anti-phase, with flow velocity output being the same, or higher, than single chamber configuration. The power efficiency (the ratio of fluidic power output to electrical power input) of the actuator with double chamber configuration is close to 15% higher than the single chamber, due to a production of two jets of velocity per cycle. A new actuator was designed and manufactured with a change in cavity height and orifice shape from the benchmark design. It was concluded that the new design is much more efficient in terms of fluidic power output however not conclusive enough to determine whether noise has been reduced further than the benchmark design.