DOI: 10.1615/ICHMT.1994.IntSympHetatTransTurb
ISBN Print: 1-56700-016-9
ISBN Print: 978-1-56700-016-0
Total Temperature Separation in an Impinging Jet: Part 2 - Supersonic Jets
ABSTRAKT
Here we extend the theme of total temperature change caused by unsteady vortical structures in jets to supersonic, underexpanded impinging jets. We find that, for sufficiently high pressure ratios, the features of the wall temperature distribution are significantly different from the subsonic impinging jet.
In an underexpanded impinging jet with a pressure ratio roughly corresponding to the first appearance of a Mach disk, wall temperatures as much as 40°C below ambient are measured at the plate center. This new, more powerful mechanism for the separation of total temperature is postulated to arise from the interaction of the vortex rings in the jet with the otherwise steady shock structure. A model is first developed by considering this interaction in the simpler case of a free jet. By then extending this argument to the impinging jet we can explain the centerline cooling.
Results from both experiments and a numerical simulation of a free jet support the model, and in fact reveal new features of vortex ring-shock interaction in a supersonic jet.