14:20   Novel experimental measurement methods V Infrared thermography and thin film gauges for heat transfer measurements of high-speed turbine blades Manuela Sisti, Chiara Falsetti, Paul Beard Abstract: This study presents the development of an infrared thermography system aimed at measuring surface temperature and heat transfer on rapidly moving targets, as turbine blades. The system was specifically engineered for the Oxford Turbine Research Facility, a rotating facility capable of matching engine Mach and Reynolds numbers, non-dimensional speed and gas-to-wall temperature ratio. Obtaining reliable infrared thermography data under rotating turbomachinery conditions poses significant challenges due to environmental reflections, low emissivity of metal components, motion-induced blur. Additionally, the transient nature of the test wit a run time of approximately 0.5 s poses challenges related to blade synchronisation and triggering, as well as the impossibility of using frame averaging to reduce random noise. To address these issues, calibration procedures were implemented using a custom-built steady-state experimental rotating rig and referenced against a traceable standard. A method for evaluating the reflected temperature from the environment was also developed and validated. Infrared thermography is utilised to capture temperature distributions across high-pressure turbine blades, enabling evaluation of surface thermal behavior, including high-resolution two-dimensional measurements of surface temperature, adiabatic wall temperature, and Nusselt number are reported for the blade tip and pressure side. Heat transfer thin-film gauges measurements on the blade pressure surface are used to highlight the capabilities of infrared thermography. This technique can be extended to other environments involving fast-moving targets or rapid thermal transients, where accurate surface temperature and heat transfer measurements are critical. Direct vapor distribution measurement for single- and multi-component evaporating droplets Hyoungsoo Kim, Minhyeok Kuk, Jeongsu Pyeon Abstract: We present an interferometric study of vapor transport characteristics in evaporating acetone-water binary and single-component sessile droplets using Mach-Zehnder laser interferometry. Simultaneously, vapor distribution near the interface is monitored to reveal key interfacial properties, including surface tension and density gradients. We report orientation-dependent evaporation behaviors for highly volatile single-component droplets such as acetone, where the difference in molecular weight between the vapor and ambient air significantly alters the evaporative flux. For binary mixtures, experiments with varying droplet orientations reveal that gravitational effects inside the droplet also influence the evaporation dynamics. This approach enables correlation of local interfacial conditions with global evaporative flux behaviors. Mach-Zehnder interferometry for measuring thin droplet shapes and refractive index fields Pierre Colinet, Senthil Parimalanathan, Alexey Rednikov, Adam Chafaï, Sam Dehaeck Abstract: Mach–Zehnder interferometry is a powerful optical technique for investigating thermo-fluidic phenomena, particularly in experiments involving contact line and phase change measurements. This study presents a comprehensive experimental framework leveraging Mach–Zehnder interferometry to analyze liquid film thickness profiles, vapor concentration fields (vapor clouds), and concentration fields in a Hele-Shaw cell. The technique is applied to sessile droplet profilometry on transparent substrates, revealing wetting dynamics, contact angle evolution, and Marangoni-driven flows and instabilities in spreading and evaporating droplets. Apart from volatile pure droplets, where the thermal Marangoni effect may be essential on account of evaporative cooling, the study also explores the role of solutal Marangoni stresses in hygroscopic binary mixtures. Additionally, vapor interferometry is employed to quantify the concentration field above evaporating droplets and liquid pools, demonstrating the method’s capability for non-invasive measurement of evaporation rates. We also showcase the application of interferometry in CO2 dissolution studies within Hele-Shaw cells. The results highlight the versatility of Mach–Zehnder interferometry in capturing all those complex phenomena, offering valuable insights for the study of evaporation, wetting, and mass transport in confined geometries. of vapor emitted from a droplet, flow in Hele-Shaw cell

end %-->