Contributor(s)

Levendis, Yiannis A., Messac, Achille, Northeastern University, Department of Mechanical Industrial and Manufacturing Engineering, Narusawa, U., Bisi, P., Hollenberg, J., Moore, D., Wilson, B., Harper, D., Jet-Vac Corporation, Albert Nerken School of Engineering, California Institute of Technology

Abstract

The purpose of this project is to create a working laboratory experiment featuring demonstrations on air flow to enhance the educational experience of mechanical engineering students at Northeastern University. Our design team constructed an experiment that is permanently housed in the basement of the Forsyth building. This experiment features demonstrations of converging-diverging nozzles with supersonic and subsonic air flows as well as demonstrations on drag and down-force in a wind-tunnel. Our experiment illustrates the tangible differences between air traveling at supersonic speed through a converging-diverging nozzle and air traveling through the same nozzle at subsonic speed. Our supersonic flow demonstration takes air supplied by an in-house air compressor and passes it through an ejector nozzle, a very small converging-diverging nozzle that accelerates the flow of air to supersonic velocities. Our subsonic flow demonstration takes the same air flow and passes it through the diffuser portion of the supersonic apparatus. The diffuser is essentially another converging-diverging nozzle. The temperature and pressure of both the supersonic and subsonic flows are measured with a series of sensors. Temperature, pressure and velocity profiles for both supersonic and subsonic flows are then generated and used to illustrate their differences. The second part of our experiment shows the aerodynamic effects of drag and down-force. The phenomenon of drag is demonstrated by subjecting two different automobile models to a blower generated air flow in a wind tunnel. The resulting drag exerted on the automobiles is measured by means a load cell. Similarly, the phenomenon of down-force is demonstrated by subjecting two different automobile models, one with a spoiler wing mounted on the trunk and one without, to the same air flow. The resulting down-force is also measured by means of a load cell. Finally, we will interface the experiments with a computer for the instantaneous display of the results in graphic form.

Notes

Capstone Design Course ME 1336-1338, Technical Design Report, Project # W971S97-2, Final report

Keywords

air flow, supersonic speed

Publisher

Northeastern University

Publication Date

8-23-2007

Rights Holder

Northeastern University, Department of Mechanical Industrial and Manufacturing Engineering

Permanent URL

http://hdl.handle.net/2047/d10010294


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