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Published April 2009 | public
Journal Article

Diagnostic modelling of an expansion tube operating condition


Computational simulations of an expansion tube were conducted to estimate flow parameters and verify experimental uncertainties. Two types of simulations of the complete facility were undertaken: a one-dimensional simulation, and a hybrid simulation where a one-dimensional simulation of the shock tube section was coupled with a two-dimensional simulation of the acceleration tube. Good agreement between the one-dimensional simulations and experiments were obtained in the shock tube portion of the facility. In the acceleration section, initial two-dimensional simulations did not match the experimentally measured pitot pressure and showed a discrepancy in the shock speed. Further studies examined how the accelerator gas composition affected shock speed, static pressure and pitot pressure levels in expansion tube operation. Subsequent two-dimensional simulations, using an 8% level of air contamination in helium, showed reasonable agreement with experimental data. This prediction of air contamination was later confirmed with experimental measurements of the air partial pressure before operation.

Additional Information

© 2009 Springer-Verlag. Received: 23 June 2008; Revised: 17 December 2008; Accepted: 29 January 2009; Published online: 17 February 2009. The authors would like to acknowledge the University of Queensland's graduate research office for financial support in the form of a Graduate Research Student Travel Award for Matthew McGilvray to visit the University of Illinois. All the simulations detailed in this paperwere undertaken on the Blackhole cluster computer located at the Centre for Hypersonics, University of Queensland. Financial support for the cluster computer was provided by SUN Microsystems and by the Queensland State government under the Smart State program. We thank Rowan Gollan, Carolyn Jacobs, Daniel Potter and Marlies Hankel for running the University of Queensland cluster computer. Experimental work was supported in part by the AFOSR/MURI Grant FA9550-04-1-0425 with Dr. John Schmisseur as program manager.

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