An electrostatic microactuator system for application in high-speed jets

The development of an electrostatic microactuator system for the study and control of high-speed jet flows is presented. The electrostatic actuator is 1.3 mm wide, 14 /spl mu/m thick and has a head that overhangs a glass substrate, intruding into the flow by 200 /spl mu/m. The actuator has been fabricated using a bulk-silicon dissolved-wafer process to increase device thickness for increased stiffness in the flow direction. Characterization of the new actuators demonstrated their ability to oscillate with amplitudes of up to 70 /spl mu/m peak-to-peak at resonant frequencies of 5 and 14 kHz. This is a very large motion at such high frequencies when compared to existing macro or micro mechanical actuators. The full actuator system was mounted around the exit of a high-speed jet using several sector-shaped PC boards. This enabled detailed examination of the ability of the actuators to withstand the flow environment and generate substantial flow disturbances. The results showed that the microactuators functioned properly up to jet speeds of 300 m/s while generating disturbances in the shear layer surrounding the jet comparable to those produced by other macro-scale methodologies.

[1]  K. Najafi,et al.  Receptivity of the Shear Layer of an Axi-Symmetric Jet to Excitation Using MEMS-Based Mechanical Actuators , 1996 .

[2]  R. Howe,et al.  Micromechanical structures for thin film characterization , 1991, TRANSDUCERS '91: 1991 International Conference on Solid-State Sensors and Actuators. Digest of Technical Papers.

[3]  Chang Liu,et al.  Silicon micromachined sensors and actuators for fluid mechanics applications , 1996 .

[4]  Chih-Ming Ho,et al.  In-plane microactuator for fluid control application , 1998, Proceedings MEMS 98. IEEE. Eleventh Annual International Workshop on Micro Electro Mechanical Systems. An Investigation of Micro Structures, Sensors, Actuators, Machines and Systems (Cat. No.98CH36176.

[5]  K. Najafi,et al.  A low-voltage bulk-silicon tunneling-based microaccelerometer , 1995, Proceedings of International Electron Devices Meeting.

[6]  Khalil Najafi,et al.  Operation and testing of electrostatic microactuators and micromachined sound detectors for active control of high speed flows , 1998, Proceedings MEMS 98. IEEE. Eleventh Annual International Workshop on Micro Electro Mechanical Systems. An Investigation of Micro Structures, Sensors, Actuators, Machines and Systems (Cat. No.98CH36176.

[7]  K. Najafi,et al.  A bulk silicon dissolved wafer process for microelectromechanical systems , 1991, International Electron Devices Meeting 1991 [Technical Digest].

[8]  Patrick Reisenthel,et al.  The dynamics of low initial disturbance turbulent jets , 1989 .

[9]  A. Powell,et al.  On the Mechanism of Choked Jet Noise , 1953 .

[10]  Yogesh B. Gianchandani.  A bulk silicon microelectromechanical system for scanning thermal profilometry. , 1994 .

[11]  William C. Tang,et al.  Electrostatic-comb drive of lateral polysilicon resonators , 1990 .

[12]  J. Lepicovsky,et al.  Tone excited jets, part III: Flow measurements , 1985 .

[13]  Karl Jiefu Ma,et al.  An active dissolved wafer process for the fabrication of integrated sensors. , 1994 .

[14]  Michael Curt Elwenspoek,et al.  Comb-drive actuators for large displacements , 1996 .

[15]  Khairul Q. Zaman,et al.  The free shear layer tone phenomenon and probe interference , 1978, Journal of Fluid Mechanics.

[16]  Albert P. Pisano,et al.  Mechanical design issues in laterally-driven microstructures , 1989 .

[17]  Khalil Najafi,et al.  Arrays of mems-based actuators for control of supersonic jet screech , 1997 .

[18]  K. Najafi,et al.  A bulk silicon dissolved wafer process for microelectromechanical devices , 1992 .

[19]  Mark G. Allen,et al.  Addressable Micromachined Jet Arrays , 1995, Proceedings of the International Solid-State Sensors and Actuators Conference - TRANSDUCERS '95.

[20]  Khalil Najafi,et al.  A microactuator system for the study and control of screech in high speed jets , 1996, Proceedings of Ninth International Workshop on Micro Electromechanical Systems.

[21]  William C. Tang,et al.  Laterally Driven Polysilicon Resonant Microstructures , 1989 .