Visualization of High-speed Boundary-layer Transition with FPA Infrared Technique.

Kurzfassung

A modern "Focal Plane Array" (FPA) infrared system was used to visualize natural transition phenomena on a 2.9 degree PTFE cone model, exposed to the hypersonic flow field of the H2K facility at flow conditions of Mach number 6 and Reynolds numbers up to 2x10xx7/m. To study bluntness influence, the model was alternately equipped with four different nose segments of 1 to 15 mm nose radius. Visualized transition locations, measured temperatures, and evaluated heat fluxes were found to be in good agreement with approximate engineering relations taken from literature. By that the infrared system has been qualified for high speed boundary-layer transition detection and the technical performance of such advanced infrared systems was demonstrated, in particular to provide experimental data to validate numerical codes for hypersonic transition prediction.