Sparkjet Development, Characterization, and Initial Implementation into a Supersonic Boundary Layer

• Other Authors: Emerick, Thomas M. (authoraut)
• Format: Others
• Language: English; English
• Published: Florida State University
• Subjects: Mechanical engineering
• Online Access: http://purl.flvc.org/fsu/fd/FSU_migr_etd-7368

Active flow control actuators have been studied rigorously by the aerodynamic community and developments have led to a wide variety of devices with various features and operating mechanisms. The design requirements for a practical actuator used for active flow control include reliable operation, requisite frequency and amplitude modulation capabilities, and a long-term lifespan while maintaining minimal cost and design complexity. An active flow control device called the SparkJet (SJ) actuator has been developed for high speed flight control and incorporates no mechanical/moving parts, zero net mass flux (ZNMF) capabilities, and the ability to tune the operating frequency and momentum throughput. This actuator utilizes electrical power to deliver high momentum flow with a very fast response time. The SparkJet actuator was characterized on the benchtop using a laser based micro schlieren visualization technique and maximum blast wave and jet front velocities of ~ 400 m/s and ~ 310 m/s were measured in the flowfield, respectively. An increase in jet front velocity from 240 m/s to 310 m/s during sub - atmospheric (60 kPa) testing reveal that the actuator may have more control authority at lower ambient pressures and high altitude conditions. A SparkJet array was integrated in to a flat plate and placed in a Mach 1.5 crossflow. Phase conditioned shadowgraph results revealed a maximum flow deflection angle of 5 degrees created by the SparkJet 275 µs after the actuator was triggered in single shot mode. Burst mode operation at 700 Hz revealed similar results during wind tunnel testing. Following these test, the actuator trigger mechanism was improved leading to an operating efficiency increase from 30% to 75% [1] and the ability of the actuator to be discharged in burst mode at a frequency of 1 kHz was achieved. === A Thesis submitted to the Department of Mechanical Engineering in partial fulfillment of the requirements for the degree of Master of Science. === Summer Semester, 2013. === April 17, 2013. === Includes bibliographical references. === Farrukh Alvi, Professor Directing Thesis; Chiang Shih, Committee Member; Patrick Hollis, Committee Member.