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Thermal and temperature measurement methods
Transition Measurements at High Reynolds Numbers using Phenol-Formaldehyde Resin
Marco Costantini, Nils van Hinsberg, Stefan Koch, Daiki Kurihara, Hirotaka Sakaue
Abstract: When excited with light in an appropriate wavelength range, certain Phenol-Formaldehyde Resins (PFRs) also emit light, which is at a wavelength larger than the excitation wavelength, and which intensity depends on the temperature. These properties are analogous to those of luminophores used in temperature-sensitive paints, but with the obvious difference that the material itself is temperature-sensitive. As a first step towards transition measurements using wind-tunnel models fully made of PFR, the current study presents an application of PFR as temperature-sensitive material for a component of a two-dimensional flat-plate model, which was previously used for the examination of the impact of surface bumps on transition. A PFR insert was machined to reproduce one of the bump configurations studied in earlier work and mounted on the model in the place of the corresponding insert. The model with the PFR insert was investigated in the Cryogenic Ludwieg-Tube Göttingen at freestream Mach numbers up to 0.77, Reynolds numbers (based on the model chord length of 0.2 m) up to 10 million, and various streamwise pressure gradients, implemented by varying the model angle-of-attack. The focus of these investigations was on the detection of bump-induced transition on the PFR insert.
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Detection and tracking of transonic flow footprints on the surface of a turbine blade using unsteady temperature-sensitive paint
Martin Bitter, Dragan Kozulovic
Abstract: Unsteady Teperature-Sensitive Paint measurements have been performed to characterize the transonic surfac e flow of a turbine blade in a linear cascade under low-pressure conditions in a Mach number range from 0.8 to 1.1. The temperature fluctuations are used to characterize surface flow footprints (e.g. shock-boundary layer interaction or shear layer separation) by means of the Taylor hypothesis.
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