Bulletin of the American Physical Society
68th Annual Meeting of the APS Division of Fluid Dynamics
Volume 60, Number 21
Sunday–Tuesday, November 22–24, 2015; Boston, Massachusetts
Session E27: Experiments: Temperature and Velocity Measurements |
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Chair: Shahram Pouya, Michigan State University Room: 308 |
Sunday, November 22, 2015 4:50PM - 5:03PM |
E27.00001: Multi-photon Molecular Tagging Thermometry with Femtosecond Excitation (FemtoMTT) Shahram Pouya, Alexander van Rhijn, Alireza Safaripour, Marcos Dantus, Manoochehr Koochesfahani Following our earlier report of first Molecular Tagging Velocimetry (MTV) measurement under nonlinear resonant femtosecond excitation in an aqueous flow, we present results of Molecular Tagging Thermometry (MTT) in a simple jet flow using femtosecond excitation. The two-photon absorption process of a phosphorescent supramolecule allows for simultaneous velocity and temperature measurement using a pair of images obtained during the lifetime of the tracer. Results reproduce the tracer temperature response under typical single photon excitation, while providing potential for high rep-rate capabilities for simultaneous velocimetry and thermometry in aqueous flows and eliminating the need for short wavelength UV excitation source and UV optical access in flow facilities. [Preview Abstract] |
Sunday, November 22, 2015 5:03PM - 5:16PM |
E27.00002: Development of a time-resolved luminescent imaging technique for unsteady temperature measurement in thermal fluid phenomena Kazunobu Kobayashi, Hirotaka Sakaue This study presents a time-resolved luminescent imaging that uses two-luminescent outputs to extract the temperature information from an acquired image. This imaging technique is applied to measure the temperature distribution for unsteady thermal fluid phenomena. The thermographic phosphors are seeded into the flow and are excited by a laser sheet as an illumination source. The luminescent images from phosphors are captured to obtain the time-resolved temperature profile by using a fast frame-rate camera as an image acquisition unit. In this study, this technique have been carried out for measurements of two-dimensional gas-phase or boiling water temperature. In the presentation, a current status of this measurement will be presented. [Preview Abstract] |
Sunday, November 22, 2015 5:16PM - 5:29PM |
E27.00003: Development of a 3-wire probe for the simultaneous measurement of turbulent velocity, concentration and temperature fields ALA\"{I}S HEWES, LAURENT MYDLARSKI The present work focuses on the design and optimization of a probe used to simultaneously measure the velocity, concentration and temperature fields in a turbulent jet. The underlying principles of this sensor are based in thermal-anemometry techniques, and the design of this 3-wire probe builds off the previous work of Sirivat and Warhaft, {\it J. Fluid Mech.}, 1982. In the first part of this study, the effect of different overheat ratios in the first two wires (called the ``interference'' or ``Way-Libby'' probe -- used to infer velocity and concentration) are investigated. Of particular interest is their effect on the quality of the resulting calibration, as well as the measured velocity and concentration data. Four different overheat ratio pairs for the two wires comprising the interference probe are studied. In the second part of this work, a third wire, capable of detecting temperature fluctuations, is added to the 3-wire probe. The optimal configuration of this probe, including wire type and overheat ratio for the third wire, is studied and the simultaneously-measured velocity, concentration, and temperature data (e.g. spectra, PDFs) for different probe configurations are presented. [Preview Abstract] |
Sunday, November 22, 2015 5:29PM - 5:42PM |
E27.00004: PIV as a temperature measurement tool Ghanem F. Oweis In particle image velocimetry (PIV), a camera records time-lapse snapshot images of the positions of particles embedded in a fluid, which faithfully trace the flow path. Cross correlating sequential particle image pairs results in 2D maps of the particle displacement and velocity fields. Here, the same PIV method is extended to temperature measurements in viscoelastic material. The motivation originates in a need for tissue temperature measurements in hyperthermia therapies such as laser ablation eye surgery and high intensity focused ultrasound (HIFU) tumor ablation. Micron sized particles are embedded in an optically clear tissue mimicking phantom, illuminated with a laser sheet, and imaged with a CCD camera. When the phantom is subjected to heating from a focused ultrasound beam, the particles remain stationary, but not their spatial distribution in the recorded images. The images manifest particle displacements commensurate with alterations in the temperature distribution from heating. The underlying principle behind the thermometric capability of PIV is discussed. Temperature changes can be detected with high sensitivity, and the method works best with spatially localized temperature distributions. [Preview Abstract] |
Sunday, November 22, 2015 5:42PM - 5:55PM |
E27.00005: A Composition-Independent Thermometry Technique for Gaseous Mixtures in Reacting Environments Dominic Zelenak, Venkat Narayanaswamy, William Sealy Temperature is an important thermochemical property that holds the key to uncovering several combustion phenomena such as pollutant formation, flame extinction, and heat release. In a practical combusting environment, the local composition is unknown, hindering the effectiveness of established non-intrusive thermometry techniques. This study aims to offset this limitation by developing a laser-based thermometry technique that does not require prior knowledge of the local composition. The Turbulent Shear Flow Laboratory (TSFL) at North Carolina State University is currently using a combination of krypton planar-laser induced fluorescence (Kr-PLIF) and Rayleigh scattering to measure temperature in reacting environments. Initial work by TSFL has studied Kr-PLIF lineshape properties of several combustion species to obtain scaling for the collisional broadening parameters based upon the properties of Kr and the surrounding environment. This information will be used to demonstrate the mean temperature profile of a 1D lean premixed CH$_{\mathrm{4}}$ flame exhaust at different downstream distances with multiple equivalence ratios for a wide range of temperatures and local compositions. Validation of the proposed technique will be made using Rayleigh scattering temperature measurements. [Preview Abstract] |
Sunday, November 22, 2015 5:55PM - 6:08PM |
E27.00006: Preparation and Application of Temperature Sensitive Paintings Chi Li Temperature sensitive painting (TSP) is a rapidly developing surface optical measurement technology, which uses temperature sensitive fluorescent probe molecular to obtain the temperature distribution on the surface of the model. Two different types of TSP material are prepared to apply in fluid mechanical experiments. Rhodamine is used as fluorescer and acetone as solvent for the first recipe, while rare earth material as fluorescer and zirconia as solvent for the second recipe. With proper calibration, surface temperature nephogram and temperature gradient nephogram is obtained based on the measured light intensity data, and transition location and heat flux is analyzed. Double layer - multi component TSP measurement technology and more strict calibration will be developed in the near future to get more precise heat flux distribution. [Preview Abstract] |
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