Investigation into the profile and flow characteristics of a contoured nozzle

Dominic Pace, Robert Krupinski, Michael Olsen, Adam Brown


Whilst operating the hypersonic contoured nozzle, researchers at the Australian Defence Force Academy (ADFA) experienced a number of experimental test section flowfield discrepancies. The greatest discrepancy that was present was that the contoured nozzle did not produce a uniform flowfield. As such, researchers were dubious about whether the manufactured profile actually matches the design profile or if the actual nozzle design had been properly scaled down from the original nozzle, which is in use at the University of Queensland.

In order to determine why the nozzle was not producing the required flowfield conditions, it was deemed necessary to compare the profiles of the designed nozzle to that of the manufactured item and establish where the laminar-to-turbulent transition point lies. The nozzle was completely disassembled and measured using coordinate measuring machines. The resultant data was used to generate an accurate profile of the nozzle. A mesh, 500 by 100 segments with an increasing resolution towards both the throat and the nozzle wall, was then applied to the manufactured nozzle’s contour with the aid of Gridgen. Computational fluid dynamic analysis was subsequently performed on the nozzle with the CFD++ program. These results were compared to the experimental data obtained from the T-ADFA shock tunnel.

It appears that the 30% turbulent point condition exhibits the closest trend pattern in comparison to the experimental data, however, the actual location will most probably lie somewhere between the 30% and 40% mark.

Overall, this was a useful investigation and has provided a good idea of the likely position of the transition point and a valuable point of reference for further investigation.

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