Bulletin of the American Physical Society
71st Annual Meeting of the APS Division of Fluid Dynamics
Volume 63, Number 13
Sunday–Tuesday, November 18–20, 2018; Atlanta, Georgia
Session Q21: Experimental Techniques: Liquid Jets, Sprays, Bubbles and Optically Dense Flows |
Hide Abstracts |
Chair: Theodore Heindel, Iowa State University Room: Georgia World Congress Center B309 |
Tuesday, November 20, 2018 12:50PM - 1:03PM |
Q21.00001: Water jet interaction with supersonic air jet Hansen Jones, Shyam Menon Spray formation following water jet injection into a supersonic air jet is investigated using various non-intrusive diagnostics. Spray characteristics are studied as a function of the jet injection location. High speed imaging is used to capture spray boundary while Phase Doppler Particle Anemometry (PDPA) is used to quantify drop size and velocity. The differences observed in the present setup from a traditional wall bounded jet-in-crossflow configuration are highlighted, including the lack of agreement with empirical relationships for spray penetration height. This is attempted to be overcome by developing new empirical relationships that take into account the diameters of the air and water jets using experimental data obtained for different sized water jets. |
Tuesday, November 20, 2018 1:03PM - 1:16PM |
Q21.00002: Visualization of flash-boiling Jets at up to five million frames per second Tariq Alghamdi, Sigurdur T Thoroddsen, Fernando Hernadez Sanchez Flash boiling of jets is important in several industrial processes, as the flash boiling offers excellent atomization characteristics when it is intentionally applied such as in some combustion systems involving fuel injection under superheated conditions. Furthermore, such jets are can be produced in high-pressure fuel leaks, where an explosive atomization and vaporization occurs spreads fine spray of droplets even far from the source. The rapid phase transition, from liquid to vapor, starts by the formation of micro-bubbles that rapidly expand and consequently break up the liquid jet. We experiment with a number of different liquids for small jet diameters in the range from 20 to 400 microns. Using ultra-high-speed video imaging at 200 ns time resolution, we observe speeds of bubble expansion as large as 140 m/s, or much faster than the jet velocity. We characterize the spray-droplet sizes, track their motions and evaluate overall spray angles which can be close to 360°. |
Tuesday, November 20, 2018 1:16PM - 1:29PM |
Q21.00003: Near-field Characterization of an Airblast Atomizer Using Broadband X-ray Radiography Danyu Li, Julie K Bothell, Timothy B Morgan, Theodore J Heindel, Nathanael Machicoane, Alberto Aliseda, Alan L Kastengren Sprays are widely used in industrial processes. X-ray measurement methods based on absorption provide useful tools that eliminate refraction and reflection that complicate visible light measurements. Synchrotron X-ray sources can provide accurate and detailed measurements because of the strong penetration of the high-energy X-rays. Compared with synchrotron X-ray sources, X-ray tube sources operate at lower energy and are easier to operate, but beam hardening and penumbra effects may complicate data analysis. However, after proper calibration, radiographs from X-ray tube sources can provide detailed information of the spray near-field compared to limited conditions from synchrotron X-ray measurements. In this research, broadband X-ray radiography is performed to obtain the time-average equivalent path length (EPL) of the spray near-field region of an airblast atomizer operating under various conditions. The EPL distributions show a Gaussian self-similar behavior in the spray near-field. Spray angles are determined by the positions of the half maximum EPL. Spray breakup length is measured and compared to high-speed white beam images from the Advanced Photon Source at Argonne National Laboratory. |
Tuesday, November 20, 2018 1:29PM - 1:42PM |
Q21.00004: High-Speed X-ray Flow Visualization of a Liquid Jet Courtney Beringer, Julie K Bothell, Timothy B Morgan, Danyu Li, Theodore J. Heindel, Alberto Osuna Aliseda, Nathanael Machicoane, Alan L Kastengren Liquid jets are found in many applications, from electronics cooling to manufacturing to cleaning. This study utilizes high intensity X-rays from the Advanced Photon Source (APS) at Argonne National Laboratory to visualize a water jet emanating from a 2.1 mm circular nozzle into an air region. Three X-ray visualization modes are employed to study the jet operating at three Reynolds numbers to cover laminar, transitional, and turbulent flow. Focused beam X-ray measurements use a 5 x 6 micron monochromatic X-ray beam to determine the jet equivalent pathlength at selected locations. Data are acquired at 6.25 MHz so high-frequency fluctuations at the gas-liquid interface can be assessed. White beam X-ray imaging provides a high intensity polychromatic X-ray beam over a larger area that allows high-speed X-ray video of the entire jet region. Image acquisition rates up to 10 kHz are captured to provide qualitative images of the entire jet. Mono beam X-ray imaging uses a larger monochromatic X-ray beam than focused beam imaging, but the beam is at a lower flux than white beam imaging. Hence, instantaneous 2D projections of the equivalent path length over the entire jet width are possible, but at slower acquisition rates than white beam imaging. |
Tuesday, November 20, 2018 1:42PM - 1:55PM |
Q21.00005: High Speed Observations of the Near-Field Region from an Electrified Airblast Atomizer Thomas Jerome Burtnett, Timothy B Morgan, Danyu Li, Julie K Bothell, Theodore J. Heindel, Alberto Osuna Aliseda, Nathanael Machicoane, Katarzyna Matuzik, Alan L Kastengren Liquid sprays play a key role in many engineering processes (e.g., food processing, coating and painting, 3D printing, fire suppression, combustion systems, etc.). The dynamics at the nozzle exit have a large impact on the downstream spray characteristics. However, visualizing the spray in this region is extremely challenging because, under most operating conditions, the spray is optically dense. High intensity white beam X-rays, like those found at the Advanced Photon Source (APS) at Argonne National Laboratory, can be used to produce time-resolved visualizations of the liquid-gas structures in the spray near-field region. In this study, high speed, high spatially resolved X-ray images are acquired of a canonical airblast atomizer consisting of coaxial water and air jets. The liquid nozzle is electrified with up to -5 kV to enhance the atomization process. Features of this electrified atomizer will be described, discussed, and compared to a non-electrified condition, and the unique high speed X-ray imaging capabilities of APS will be stressed. |
Tuesday, November 20, 2018 1:55PM - 2:08PM |
Q21.00006: Optimal Vessel Materials for Ultrasound Metrology Bitong Wang, Douglas H Kelley Ultrasound metrology can measure flow velocity in a non-invasive way. However, the wall of the vessel between the ultrasound transducer and the test fluid plays an important role. Our study aims to find the vessel material that most efficiently transmits sound between the ultrasound transducer and the test fluid, in order to optimize signal strength and minimize the influence of the wall. In this study, we investigated the effect of different wall materials on the echo intensity and velocity measurements in water and liquid gallium. Comparing theoretical predictions from acoustic transmission models to experimental results, we also explored the effect of the thickness of the wall. Our study suggests that transmission coefficients alone cannot predict the performance of wall materials accurately. The work presented here opens a way to perform high precision ultrasound measurement through vessel walls. |
Tuesday, November 20, 2018 2:08PM - 2:21PM |
Q21.00007: Interface Identification in Falling-Film Flows by Structured Laser-Induced Fluorescence Alexanros Charogiannis, Christos N Markides A structured laser-induced fluorescence technique (S-PLIF) was developed towards the reliable time- and space-resolved measurement of film-thickness in gas-liquid annular flows. Recently, "conventional" techniques such as planar laser-induced fluorescence (PLIF) and brightness-based laser induced fluorescence (BBLIF) were shown to suffer from large errors induced by total internal reflection (TIR) and refraction at the gas-liquid interface, depending on the interface toplogy. With this novel variation of PLIF we exploit TIR in order to locate the free surface with a high degree of accuracy, and compare our results to simultaneously recovered PLIF data, as well as data from other techniques. Our experiments show that S-PLIF outperforms PLIF when the observation angle is set to 70 o, as any distortions caused by refraction of the emitted fluorescence are suppressed. Image-processing methodologies were developed based on the identification of gradient variations in the S-PLIF images, and the employment of a commercial 2D particle image velocimetry (PIV) code. |
Tuesday, November 20, 2018 2:21PM - 2:34PM |
Q21.00008: A High Speed Scanning Electron Beam X-ray Tomography System for Optically Opaque Flows Kevin Xu, Harish Ganesh, Simo Makiharju, Steven Ceccio Computational fluid dynamics tools are becoming increasingly capable of modelling complex multiphase flows with the advancement of modern computing and high-fidelity codes. As these codes become increasingly capable, the need to verify and validate the physical models though accurate experimental measurements with well characterized uncertainty becomes ever more important. Development of a true 3D (initially 4-plane) scanning electron beam X-ray tomography system was undertaken to image and measure void fraction distributions of optically opaque flows. A 20 kW electron beam that can be rapidly focused and deflected, thus varying X-ray source location, allows us to generate limited-angle projection data of an object of interest at O(kHz) rates. Limited-angle tomography with reduced artifacts is achieved using a statistical reconstruction algorithm to produce cross-sectional images of flows. Evaluation of the system performance is done via the use of a static and a dynamic phantom emulating bubbly flow. Preliminary data of a bubbly flow are also presented. |
Tuesday, November 20, 2018 2:34PM - 2:47PM |
Q21.00009: Validating advection-corrected correlation image velocimetry Gregory Vigil, Peter V Vorobieff, Daniel Freelong, Patrick Wayne, C Randall Truman We investigate the formation and subsequent shock acceleration of a gravity-driven curtain of massive particles, where the initial particle volume fraction in the curtain can vary between 1 and 10%. The process of the curtain formation and evolution is recorded in two imaging planes (planar and side views). The high seeding density of the particles in the curtain presents a challenge for visualization and analysis using laser-sheet techniques such as particle image velocimetry. Instead of laser sheets, we have to rely on diffuse constant-intensity light for visualization. The resulting images allow us to apply several techniques: particle-image velocimetry (with a caveat that the plane of visualization is defined not by the lighting, but by the flow geometry and the camera depth of focus), particle tracking, and image-correlation velocimetry with advection correction. Comparison between the results also presents us with an excellent opportunity to cross-validate the diagnostics. |
Tuesday, November 20, 2018 2:47PM - 3:00PM |
Q21.00010: Particle Image Velocimetry with an Acoustic Camera David L. Young, Brian C. McFall, Duncan B. Bryant We performed PIV analysis on images acquired with an acoustic camera (AC) to measure the flow in the wake of a circular cylinder at two flowrates. The AC observes micro-bubbles suspended in the flow which were used as tracer particles ("bubble image velocimetry"). The size distribution of the bubbles is measured with an acoustic bubble spectrometer (ABS). The AC PIV measurements of the wake agree well with the comparison measurements made by cross-stream arrays of acoustic Doppler velocimeters (ADVs) for the lower flowrate. The AC PIV measurements of cross-stream profiles of the mean downstream velocities and the profiles of characteristics of the velocity fluctuations all matched the ADV measurements well. However, the technique is sensitive to bubble size distribution, as the higher flowrate AC PIV measurements struggled to replicate the ADV measurements, particularly the velocity fluctuations. The higher flowrate experiment has an order of magnitude more bubbles with size exceeding 15 μm present in the flow than the lower flowrate experiment. The increased bubble density caused a “flickering” effect, with bubbles further away from the camera being intermittently obscured by those closer to the camera. |
Tuesday, November 20, 2018 3:00PM - 3:13PM |
Q21.00011: The Twente mass and heat transfer tunnel Dennis P.M. van Gils, Gert-Wim Bruggert, Biljana Gvozdić, On-Yu Dung, Sander G. Huisman, Chao Sun, Detlef Lohse We present a newly-built recirculating vertical water tunnel with global temperature control, bubble injection and local heat/mass injection for the study of local heat and mass transfer in turbulent (bubbly) flows. The tunnel is made of high-grade stainless steel permitting the use of salt solutions in excess of 15% mass fraction, besides clear water. The tunnel volume is 300 liters. Three interchangeable measurement sections of 1 m in height but of different aspect ratios (0.3 x 0.04 m2, 0.3 x 0.06 m2, 0.3 x 0.08 m2) span a Reynolds-number range from 5 x 103 to 1.6 x 105 in the case of clear water at room temperature. |
Tuesday, November 20, 2018 3:13PM - 3:26PM |
Q21.00012: Abstract Withdrawn |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700