Dense Spray Properties Structure And Turbulence Modulation PDF Download
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| Author | : G. A. Ruff |
| Publisher | : |
| Total Pages | : 119 |
| Release | : 1989 |
| Genre | : |
| ISBN | : |
Download Dense-Spray Properties: Structure and Turbulence Modulation Book in PDF, ePub and Kindle
A theoretical and experimental study of aspects of dense sprays is described, considering: the structure and mixing properties of the near-injector, dense-spray region of pressure-atomized sprays; and the direct effect of particle (drop) motion on the turbulence properties of multiphase flows (which is often called turbulence modulation). The structure of dense sprays was studied using large-scale (9.5 and 19.1 mm jet exit diameters) water sprays in still air. Measurements included: flow visualization using flash photography; liquid volume fractions using gamma-ray absorption; streamwise mean and fluctuating velocities at the injector exit, and entrainment velocities, using laser velocimetry; and dispersed-phase properties using single- and double-flash holography. Predictions based on the locally-homogeneous flow (LHF) approximation of multiphase flow theory were evaluated using the measurements. Measurements showed that mixing was strongly influenced by the degree of flow development at the injector exit and the breakup regime: fully-developed flow and atomization breakup yielded the fastest mixing rates. Turbulence modulation was studied by considering nearly monodisperse spherical glass particles falling in a stagnant water bath, where effects of turbulence modulation were responsible for the entire turbulence field. Measurements included phase velocities, as well as the temporal and spatial correlations of continuous-phase velocities, using a two-point phase-discriminating laser velocimeter; and calibration of particle motion properties using motion-picture shadowgraphs. (JHD).
| Author | : R. N. Parthasarathy |
| Publisher | : |
| Total Pages | : 92 |
| Release | : 1988 |
| Genre | : |
| ISBN | : |
Download Turbulence Modulation and Dense-Spray Structure Book in PDF, ePub and Kindle
A theoretical and experimental study of phenomena related to dense sprays is described. Two aspects of dense sprays are being considered: effects of turbulence modulation, which is the direct effect of particle (drop) motion on the turbulence properties of multiphase flows; and the structure and mixing properties of the dense-spray region of pressure atomized sprays. Turbulence modulation is being studied by considering spherical monodisperse glass particles falling in a stagnant water bath, where effects of turbulence modulation are responsible for the entire turbulence field. Measurements involve phase velocities and temporal and spatial correlations and spectra of the continuous phase velocities using a two-point phase-discriminating laser Doppler anemometer. Flow properties are being analyzed using stochastic methods: assuming linear superposition of randomly arriving particle wakes (Poisson statistics) for liquid phase properties; and random-walk calculations based on statistical time-series methods for particle properties. Multiphase flow, Sprays, Particle-laden flow. (jes).
| Author | : R. N. Parthasarathy |
| Publisher | : |
| Total Pages | : 81 |
| Release | : 1987 |
| Genre | : |
| ISBN | : |
Download Dense-Spray Structure and Phenomena. Part 1. Turbulence/Dispersed-Phase Interactions Book in PDF, ePub and Kindle
This report describes one aspect of an investigation of dense-spray processes: namely turbulence/dispersed-phase interactions. The work was divided into two phases: (1) measurements of particle-laden jets injected into a still liquid; and homogenous particle flows, consisting of particles falling in a still (in the mean) liquid bath. The structure of turbulent, dilute, particle-laden water jets, submerged in still water, was studied both experimentally and theoretically. Nonintrusive measurements were made of mean and fluctuating phase velocities and particle number fluxes. Analysis was used to help interpret the measurements, considering three limiting cases, as follows: (1) locally-homogenous flow, where relative velocities between the phases are ignored; (2) deterministic separated flow, where relative velocities are considered, but particle/turbulence interactions are ignored; and (3) stochastic separated flow, where both phenomena are considered using random-walk methods. The locally-homogenous flow approximation was more effective than for past work involving larger density ratios between the phases; nevertheless, stochastic analysis yielded best agreement with measurements. Effects of enhanced drag (due to high relative turbulent intensities of particle motion) and effects of particles on liquid turbulence properties (turbulence modulation), were observed. Several recent proposals for treating these phenomena were examined; however, none appears to be adequate for reliable general use.
| Author | : |
| Publisher | : |
| Total Pages | : 372 |
| Release | : 1994 |
| Genre | : Aeronautics |
| ISBN | : |
Download Scientific and Technical Aerospace Reports Book in PDF, ePub and Kindle
| Author | : |
| Publisher | : |
| Total Pages | : 560 |
| Release | : 1988-05 |
| Genre | : Science |
| ISBN | : |
Download Technical Reports Awareness Circular : TRAC. Book in PDF, ePub and Kindle
| Author | : |
| Publisher | : |
| Total Pages | : 1072 |
| Release | : 1986 |
| Genre | : Mechanics, Applied |
| ISBN | : |
Download Applied Mechanics Reviews Book in PDF, ePub and Kindle
| Author | : R. Borghi |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 958 |
| Release | : 2013-03-08 |
| Genre | : Science |
| ISBN | : 146139631X |
Download Turbulent Reactive Flows Book in PDF, ePub and Kindle
Turbulent reactive flows are of common occurrance in combustion engineering, chemical reactor technology and various types of engines producing power and thrust utilizing chemical and nuclear fuels. Pollutant formation and dispersion in the atmospheric environment and in rivers, lakes and ocean also involve interactions between turbulence, chemical reactivity and heat and mass transfer processes. Considerable advances have occurred over the past twenty years in the understanding, analysis, measurement, prediction and control of turbulent reactive flows. Two main contributors to such advances are improvements in instrumentation and spectacular growth in computation: hardware, sciences and skills and data processing software, each leading to developments in others. Turbulence presents several features that are situation-specific. Both for that reason and a number of others, it is yet difficult to visualize a so-called solution of the turbulence problem or even a generalized approach to the problem. It appears that recognition of patterns and structures in turbulent flow and their study based on considerations of stability, interactions, chaos and fractal character may be opening up an avenue of research that may be leading to a generalized approach to classification and analysis and, possibly, prediction of specific processes in the flowfield. Predictions for engineering use, on the other hand, can be foreseen for sometime to come to depend upon modeling of selected features of turbulence at various levels of sophistication dictated by perceived need and available capability.
| Author | : G. M. Faeth |
| Publisher | : |
| Total Pages | : 6 |
| Release | : 1990 |
| Genre | : |
| ISBN | : |
Download Drop/Gas Interactions in Dense Sprays Book in PDF, ePub and Kindle
Two drop/gas interactions important in the near-injector dense region of sprays are being studied: (1) turbulence modulation, which is the direct generation or modification of turbulence by drop motion, and (2) secondary drop breakup, an important rate-controlling process in dense sprays. Effects of turbulence modulation were measured in homogeneous flows generated by particles falling in stagnant air and water baths. The flow was analyzed with a simple stochastic approach, involving linear superposition of randomly-arriving particle velocity fields. Guided by the theory, unified correlations of turbulence properties were achieved for the measurements. Further progress requires more information about particle wake properties at modest Reynolds numbers in turbulent fields: this is the main focus of current work. Secondary drop breakup is being studied using a shock tube and various drop generators, emphasizing near-limit breakup which is most relevant to dense sprays. Work thus far has concentrated on definition of deformation and shear breakup regimes. This will be followed by study of breakup dynamics and outcomes using holocinematography instrumentation that was recently developed in this laboratory. Keywords: Multiphase flow, Homogeneous turbulence, Drop breakup. (jhd).
| Author | : |
| Publisher | : |
| Total Pages | : 480 |
| Release | : 1990-02 |
| Genre | : Science |
| ISBN | : |
Download Government Reports Announcements & Index Book in PDF, ePub and Kindle
| Author | : N. Swaminathan |
| Publisher | : Cambridge University Press |
| Total Pages | : |
| Release | : 2022-01-06 |
| Genre | : Technology & Engineering |
| ISBN | : 1108572758 |
Download Advanced Turbulent Combustion Physics and Applications Book in PDF, ePub and Kindle
Explore a thorough and up to date overview of the current knowledge, developments and outstanding challenges in turbulent combustion and application. The balance among various renewable and combustion technologies are surveyed, and numerical and experimental tools are discussed along with recent advances. Covers combustion of gaseous, liquid and solid fuels and subsonic and supersonic flows. This detailed insight into the turbulence-combustion coupling with turbulence and other physical aspects, shared by a number of the world leading experts in the field, makes this an excellent reference for graduate students, researchers and practitioners in the field.
