Bulletin of the American Physical Society
72nd Annual Meeting of the APS Division of Fluid Dynamics
Volume 64, Number 13
Saturday–Tuesday, November 23–26, 2019; Seattle, Washington
Session H11: Experimental Techniques: General |
Hide Abstracts |
Chair: Amy McCleney, Southwest Research Institute Room: 3B |
Monday, November 25, 2019 8:00AM - 8:13AM |
H11.00001: An Experimental Investigation of Surfactant Effects on the Wave Characteristics of Annular Flows Andrius Patapas, Victor Voulgaropoulos, Valeria Garbin, Ronny Pini, Christos Markides, Omar Matar, Karl Anderson While a wide scope of research has been performed in the field of multiphase flows, the study of surface active agents in gas-liquid annular flows has lagged despite their ability in considerably improving heat and mass transfer rates. More detailed insight is still needed to promote quantitative interpretations of the surfactant-induced effects on the wave characteristics and entrainment properties of these thin films. In this work, we study water-air annular pipe flows in both the presence and absence of a water-soluble fluorescent surfactant. The liquid Reynolds numbers, based on the film properties, range between 400 to 1500. We perform structured planar laser-induced fluorescence (S-PLIF) measurements to accurately obtain film-thickness measurements and reveal the temporal characteristics of the waves. We further explore the differences on the entrainment rates and size of the bubbles in the liquid films for both cases, by visualising the flow from two observation angles. Surfactant-tracking diagnostic methods are also currently being developed. [Preview Abstract] |
Monday, November 25, 2019 8:13AM - 8:26AM |
H11.00002: Laser Cantilever Anemometry for highly resolved velocity measurements in fluids Jaroslaw Puczylowski Laser Cantilever Anemometry is a new and high-resolution measurement method for determining the velocity vector of a fluid. A micro-structured silicon cantilever serves as a drag body that is set into the flow. The forces acting on the cantilever, which are exerted by the moving fluid particles, cause the cantilever to bend or twist. With the help of the laser pointer principle, this deformation can be detected and finally recalculated into a velocity vector in two dimensions. The measuring principle is characterized by a very high temporal and spatial resolution (approx. 100\textmu m at 100kHz). In the recent past a sensor was developed and tested, which uses this measuring method. The so-called 2d-LCA (2d-Laser Cantilever Anemometer) was extensively and successfully used under different laboratory conditions. The current version of the 2d-LCA has the size of a highlighter and is operated via USB-C or Bluetooth. This compact design is extremely portable and allows the use in difficult to access areas. In addition, all hardware components of the 2d-LCA are made of Invar (Alloy36), which has a very low coefficient of thermal expansion. This avoids heat-related drift and leads to a very stable signal. At the The 72nd Annual Meeting of the American Physical Society's Division of Fluid Dynamics (DFD), the measuring principle of the 2d-LCA will be explained in more detail and measurement results will be presented. [Preview Abstract] |
Monday, November 25, 2019 8:26AM - 8:39AM |
H11.00003: Development of Focused Laser Differential Interferometry for Hypersonic Freestream Measurements Joel Lawson, Mallory Neet, Joanna Austin Focused laser differential interferometry (FLDI) is a non-invasive diagnostic capable of making localized density measurements with high temporal resolution. Its distinguishing feature for ground testing is diminished response away from the focal plane, thereby mitigating signal contributions from fluid not in the facility core flow. We first present a quantitative experimental validation of a ray-tracing scheme used to model the FLDI response. This is followed by some applications of the technique to Caltech's hypersonic ground testing facilities: firstly, FLDI is applied to the Hypervelocity Expansion Tube (HET) to measure the freestream noise spectrum during test time, and relating this to the initial driver gas state as per the acoustic wave theory of Paull and Stalker [J. Fluid Mech., vol. 245, pp. 493-521, 1992]. Secondly, FLDI is used to track a laser-induced breakdown in the freestream of the T5 reflected shock tunnel, with the goal of measuring flow velocity and sound speed. [Preview Abstract] |
Monday, November 25, 2019 8:39AM - 8:52AM |
H11.00004: Weighted Least squares density reconstruction for Background Oriented Schlieren (BOS) Lalit Rajendran, Jiacheng Zhang, Sally Bane, Pavlos Vlachos Background Oriented Schlieren (BOS) is an optical technique used to measured density gradients by tracking the apparent distortion of a dot pattern. The density gradient field can then be spatially integrated to calculate the density field. The Poisson solver is currently the standard for density integration, but it is sensitive to noise in the gradient field. We address this limitation and improve the overall accuracy of the density integration process by employing a weighted least-squares (WLS) method. WLS performs the 2D integration of a gradient field by solving an over-determined system of equations. Weights are assigned to the grid points based on errors/uncertainties in the density gradient field to ensure that a less reliable measurement point is given less weight on the integration procedure. This method has been shown to increase the robustness of the integration in velocity-based pressure estimation, and in this study we will assess its suitability for BOS. We will assess the calculation of weights based on two methods: (1) based on the displacement uncertainty and (2) using a curl-free constraint on the density gradient field, as the underlying density field is a scalar. The contribution is an improved integration method for density estimation from BOS. [Preview Abstract] |
Monday, November 25, 2019 8:52AM - 9:05AM |
H11.00005: A quantitative analysis of the chemical evolution of an iodine plume using optical filtering, imaging spectroscopy, and schlieren imaging Sara DiGregorio, Alexandra Rivera, Michael Hargather The chemical evolution of an iodine plume was quantitatively analyzed using a dual high-speed camera imaging system and verified using imaging spectroscopy. The dual high-speed camera imaging system consisted of a single parallel light lens schlieren system with a beamsplitter located after the knife-edge to send the light into two Photron Mini AX cameras. Each camera imaged through an optical notch filter, one at 520 nm and one at 650 nm. The 520 nm and 650 nm filters correspond to the maximum absorption wavelength and zero absorption wavelength of the iodine absorption spectra, respectively. A turbulent plume, consisting of vaporized iodine and a carrier gas, was imaged in the dual camera system. The resulting image sets were processed to relate differences in pixel intensity to light absorption intensity of the developing plume. The plume’s iodine concentration was then derived from the changes in absorption intensity. A validation system, using a Horiba MicroHR imaging spectrometer and a Photron SA-X2 camera, measured the iodine plume’s absorption spectra directly and verified the accuracy of the optical filtering technique. Results show the ability to perform simultaneous refractive imaging and species identification in a turbulent flow field. [Preview Abstract] |
Monday, November 25, 2019 9:05AM - 9:18AM |
H11.00006: Measurement of high frequency temperature fluctuations in high-pressure premixed combustion using laser Rayleigh scattering Han June Park, Sangeun Bae, Hyungrok Do, Wontae Hwang In gas turbines, the high temperature and pressure combustion environment makes it difficult to measure physical properties such as flame characteristics. This measurement issue is also crucial when assessing combustion instability. Thermoacoustic combustion instability is known to occur when heat release and acoustic oscillations become in phase with each other. Due to the nature of heat release oscillation, modeling and measurement are difficult. To measure heat release oscillations, temperature fluctuation measurements are necessary. However, previous research in high temperature and pressure environments has been limited. In this study, we measured high frequency temperature fluctuations in high-pressure premixed combustion through density fluctuations, using non-intrusive laser Rayleigh scattering. The photon counting method was applied to quantify low intensity Rayleigh scattering. In addition, a high-speed camera was used to correlate the flame shape and combustion instability as pressure increases. [Preview Abstract] |
Monday, November 25, 2019 9:18AM - 9:31AM |
H11.00007: Planar spray visualization processing techniques and considerations Kyle M. Bade, Rudolf J. Schick Techniques to visualize and characterize spray distributions include mechanical and optical methods. Planar laser illumination presents a non-intrusive and direct method to visualize and quantify the size, shape, and distribution of a spray across a known cross-section. The nuances of processing and interpreting the light intensity from polydisperse sprays can have a significant effect on the resulting relative distribution of the scattered light. Mie scattered light is proportional to the surface area of the droplet, while laser induced fluorescence (LIF) emits an intensity proportional to the spray volume. As a result, processing of instantaneous droplet fields using both techniques may recover an effective Sauter Mean Diameter (D32), this process is explained and demonstrated. It is well understood that collected scattered light intensity is proportional to the number of droplets as well as the size of those droplets, with increasing numbers and diameter deliver a higher intensity. Additionally, the scattering angle and position of a droplet relative to the illumination source and collection device (camera) effect the perceived local concentration. The effects of these, and other details, are demonstrated and explained in the context of the Spraying Systems Co. SprayScan$^{\mathrm{TM}}$ mPT instrument as well as for general experimental setups. [Preview Abstract] |
Monday, November 25, 2019 9:31AM - 9:44AM |
H11.00008: 2D X-ray Radiography and 3D Computed Tomography of a Spray Danyu Li, Theodore J. Heindel X-ray computed tomography can provide a comprehensive three-dimensional time-average view of a spray with clear internal details. Compared with general X-ray radiography, however, it is time-consuming and the 3D reconstructions require specialized imaging tools. For axisymmetric sprays, it is possible to calculate the 3D density distribution from the 2D X-ray radiographs. In this research, broadband tube source X-rays were used to take 2D radiographs of a spray from a two-fluid coaxial atomizer. To enhance image contrast, 20{\%} potassium iodide by mass was added to the water. Based on the circular symmetry of the spray, an Abel inversion was used to analyze the time-average radial density distribution of the spray. X-ray computed tomography was also used to quantify the internal structure and the radial density distribution of the identical spray. The results of the two were compared and show good agreement as long as the spray is axisymmetric. [Preview Abstract] |
Monday, November 25, 2019 9:44AM - 9:57AM |
H11.00009: A Near-field Comparison of Flows at Similar Momentum Ratios in a Co-Flow Airblast Atomizer Thomas J. Burtnett, Timothy B. Morgan, Danyu Li, Julie K. Bothell, Theodore J. Heindel, Alberto Aliseda, Nathanael Machicoane, Alan L. Kastengren Spray atomizers can be found in a wide variety of applications, from combustion systems to nasal inhalers. Capturing the dynamics of sprays and their formation in the near-field region are often challenging due to their optically dense nature. In this study, a co-flow airblast atomizer was used to disperse a stream from an inner liquid needle. Gas and liquid flow rate combinations were varied to achieve conditions with similar gas-liquid momentum ratios. The high-resolution X-ray capabilities at the Advanced Photon Source at Argonne National Laboratory were used to characterize the near-field spray formation region. Quantitative results from focused-beam X-ray measurements, such as the fluid's equivalent path length (EPL), were determined and compared for various momentum ratios. Similar momentum ratios provided similar EPL measures in selected regions, even while the gas and liquid Reynolds numbers were varied. Regions where differences appeared for the same momentum ratio are also identified and discussed. [Preview Abstract] |
Monday, November 25, 2019 9:57AM - 10:10AM |
H11.00010: Effects of Shape, Surface Area, and Volume on Dissolution of Inertial Particles in Turbulence Theresa B. Oehmke, Evan A. Variano Turbulent environments are abundant in nature, yet they are still not completely understood. Research on particles in turbulence has focused mainly on spherical particles smaller than the viscous scale even though many organisms found in nature exceed the size of the turbulent viscous length-scale and are not spherical in shape. Sea Walnuts and other zooplankton fall into this shape and size ranges of interests. These organisms have long been considered important species in ocean ecosystems. I am interested in understanding how these organisms exchange soluble material with their environment. Using dissolving sugar particles as a proxy, I investigate the fundamental questions of how shape, surface area, and volume affect particle dissolution rates in a laboratory turbulence tank. The research thus far has shown that neither surface area nor volume alone govern the dissolution rate of dissolving particles. Determining a single governing parameter may help elucidate how organisms interact with their environment and can contribute to the design of mini robots with respect to how they sample concentration plumes in rivers, streams, oceans, and other bodies of water. [Preview Abstract] |
Monday, November 25, 2019 10:10AM - 10:23AM |
H11.00011: Multiphase liquid entrainment measurements in high pressure piping Amy McCleney A two-phase flow of natural gas and liquid heptane flowing in 3-inch and 6-inch diameter pipes pressurized up to 3,600 psig is characterized using a combination of a novel liquid sampling technique and a flow imaging technique. The results from this new measurement approach show how the phase distribution inside of the piping can be obtained as well as how the liquid entrainment fraction changes with an increase in gas and liquid velocity. In the petroleum industry, multiphase flows are encountered during natural gas production and processing. In two-phase flow scenarios, the amount and distribution of liquid in the gas stream play an important role in the selection and operation of flow measurement devices and the design of gas processing and separation equipment. The improper design of these types of equipment can negatively affect the allocation of petroleum resources. Several experimental tests have been conducted to investigate and characterize two-phase flows in pipes with low liquid levels but are based on experimental data collected at pressures less than 100 psig. This study indicates that the pressure has a significant effect in the distribution and behavior of two-phase flow mixtures, as the natural gas will dissolve in the liquid phase as the pressure increases. [Preview Abstract] |
Monday, November 25, 2019 10:23AM - 10:36AM |
H11.00012: Optical measurements of the velocity, height and frequency of disturbance waves in saturated two-phase annular flow. Tiago Moreira, Roman Morse, Kristofer Dressler, Gherhardt Ribatski, Louise McCarroll, Evan Hurlburt, Gregory Nellis, Arganthael Berson In~two-phase~annular flows, disturbance waves, i.e., large waves~several times thicker than the mean thickness of the liquid film,~strongly affect the~heat transfer coefficient and pressure drop. In this study, an optical~technique is~used~to simultaneously~measure~the~instantaneous velocity and height, as well as the frequency of~disturbance waves~in an adiabatic two-phase annular flow of saturated R245fa.~Instantaneous liquid film thickness is measured using the optical method initially~proposed by Shedd and Newell (1998,~\underline {https://doi.org/10.1063/1.1149232}). In this method,~the liquid film thickness is calculated from~ring patterns made by light reflected at the interface of the liquid film. A new strategy for the post-processing of the ring patterns~has been~developed~that~allows~the~measurement of the instantaneous~disturbance wave velocities. Detailed characterization of wave velocity, height,~and frequency will be presented for flows with vapor qualities between~0.63~and~0.9. Results show that disturbance waves become slower and~less frequent~at the high vapor qualities. [Preview Abstract] |
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. |
© 2025 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