Abstract
Micro devices have been widely used in aerospace engineering for years. Engineers are interested in applications of micro devices such as microjets, micro actuators, and micronozzles. The small size nozzles can be used for attitude adjustment and propulsion of micro-satellites or mini-spacecraft. In this paper, convergent-divergent micronozzles have been investigated at supersonic speed with various total pressures and Reynolds numbers. The throat of the micronozzle is 250 micron wide and the nozzle is designed as de Laval type. For the measurements, the Reynolds number at the throat varies from 1200 to 11000 and total pressure varies from 6 psia to 55 psia. Experimental results are obtained with pressure-sensitive paint for pressure measurement and schlieren imaging for flow visualization. Flow visualization is a challenge for conventional techniques due to the small length scales and small depth of the density gradient. A modified schlieren technique is used to increase the sensitivity by taking the ratio of wind-on and wind-off images. Pressure-sensitive paint is also used to obtain global pressure measurement of the flow field and to compare with the schlieren results.
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Chihyung Huang: He received his B.S. and M.S. degrees in Aerospace Engineering from Tamkang University, Taiwan in 1995 and National Cheng Kung University, Taiwan 1997. Now he received his Ph.D. in School of Aeronautics and Astronautics at Purdue University. His current research interest is to apply PSP measurements in micro devices such as micronozzle, microjet, microchannel, and microturbine. He is now working as postdoctoral fellow in School of Industrial Engineering at Purdue University.
James W. Gregory: He received his Ph.D. (2005) and M.S. (2002) in Aeronautics and Astronautics from Purdue University, and a Bachelor of Aerospace Engineering from Georgia Tech in 1999. He is an NRC Postdoctoral Research Fellow at the US Air Force Academy. His work involves development of pressure-sensitive paint for unsteady aerodynamic applications, as well as the development of plasma actuators and fluidic oscillators as flow control actuators. He has been honored with the AIAA Wright Brothers Graduate Award (2005), the Boeing Engineering Student of the Year Award (2006), and first place in the AIAA National Student Paper Competition (2004).
John P. Sullivan: He received his B.S. in mechanical and aerospace sciences with honors from the University of Rochester in 1967, MS in 1969 and ScD in 1973 in aeronautical engineering from the Massachusetts Institute of Technology. Professor Sullivan has been a faculty member in the School of Aeronautics and Astronautics at Purdue since 1975, served as the director of the Aerospace Sciences Laboratory from 1983–1995, Head of the School from 1993–1998, and is Director of the Center for Advanced Manufacturing since 2004. His research interests include experimental aerodynamics, as well as advanced measurement techniques in fluid dynamics.
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Huang, C., Gregory, J.W. & Sullivan, J.P. Flow visualization and pressure measurement in micronozzles. J Vis 10, 281–288 (2007). https://doi.org/10.1007/BF03181695
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DOI: https://doi.org/10.1007/BF03181695