Download or read book Dense Spray Structure and Phenomena Part 1 Turbulence Dispersed Phase Interactions written by R. N. Parthasarathy and published by . This book was released on 1987 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1990 with total page 996 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1989 with total page 1148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1988-05 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1988 with total page 1132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1988 with total page 1590 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
Download or read book Government Reports Annual Index Keyword A L written by and published by . This book was released on 1988 with total page 1600 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Reactive Flows written by R. Borghi and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 958 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1990 with total page 1208 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transport Phenomena with Drops and Bubbles written by Satwindar S. Sadhal and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid flows that transfer heat and mass often involve drops and bubbles, particularly if there are changes of phase in the fluid in the formation or condensation of steam, for example. Such flows pose problems for the chemical and mechanical engineer significantly different from those posed by single-phase flows. This book reviews the current state of the field and will serve as a reference for researchers, engineers, teachers, and students concerned with transport phenomena. It begins with a review of the basics of fluid flow and a discussion of the shapes and sizes of fluid particles and the factors that determine these. The discussion then turns to flows at low Reynolds numbers, including effects due to phase changes or to large radial inertia. Flows at intermediate and high Reynolds numbers are treated from a numerical perspective, with reference to experimental results. The next chapter considers the effects of solid walls on fluid particles, treating both the statics and dynamics of the particle-wall interaction and the effects of phase changes at a solid wall. This is followed by a discussion of the formation and breakup of drops and bubbles, both with and without phase changes. The last two chapters discuss compound drops and bubbles, primarily in three-phase systems, and special topics, such as transport in an electric field.
Download or read book This is your war written by Marion Yass and published by . This book was released on 1983 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dense Spray Properties Structure and Turbulence Modulation written by G. A. Ruff and published by . This book was released on 1989 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).
Download or read book Turbulence Modulation and Dense Spray Structure written by R. N. Parthasarathy and published by . This book was released on 1988 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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).
Download or read book Experiments and Numerical Simulations of Diluted Spray Turbulent Combustion written by Bart Merci and published by Springer Science & Business Media. This book was released on 2011-06-20 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reflects the outcome of the 1st International Workshop on Turbulent Spray Combustion held in 2009 in Corsica (France). The focus is on reporting the progress of experimental and numerical techniques in two-phase flows, with emphasis on spray combustion. The motivation for studies in this area is that knowledge of the dominant phenomena and their interactions in such flow systems is essential for the development of predictive models and their use in combustor and gas turbine design. This necessitates the development of accurate experimental methods and numerical modelling techniques. The workshop aimed at providing an opportunity for experts and young researchers to present the state-of-the-art, discuss new developments or techniques and exchange ideas in the areas of experimentations, modelling and simulation of reactive multiphase flows. The first two papers reflect the contents of the invited lectures, given by experts in the field of turbulent spray combustion. The first concerns computational issues, while the second deals with experiments. These lectures initiated very interesting and interactive discussions among the researchers, further pursued in contributed poster presentations. Contributions 3 and 4 focus on some aspects of the impact of the interaction between fuel evaporation and combustion on spray combustion in the context of gas turbines, while the final article deals with the interaction between evaporation and turbulence.
Download or read book Drop Gas Interactions in Dense Sprays written by G. M. Faeth and published by . This book was released on 2001 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence generation and liquid breakup are being studied due to their relevance to dense combusting sprays found in propulsion systems. Turbulence generation is the main source of turbulence in dense sprays; it consists of drop wake disturbances embedded in a turbulent interwake region. Both regions are unusual compared to conventional fluid flows: the drop wakes are laminar-like turbulent wakes typical of intermediate Reynolds number wakes in turbulent environments; the turbulent interwake region consists of isotropic turbulence in the little-studied final decay period. Work already completed has resolved the properties of the turbulent interwake region and overall flow properties for monodisperse particle (drop) flows; current work is addressing these properties for more practical polydisperse particles (drops). Primary and secondary liquid breakup are important because they are the rate-controlling processes of dense sprays and fix initial conditions for dilute sprays. Past work has shown that liquid breakup should be treated as a rate process and has provided the temporal properties of secondary drop breakup at large liquid/gas density ratios based on experiments. Current work is considering drop deformation and breakup based on time-dependent numerical simulations, emphasizing conditions where liquid/gas density ratios are small and effects of liquid viscosity are large, which are important for practical applications but are difficult to consider using experiments.
Download or read book ICLASS 97 written by ILASS. and published by . This book was released on 1997 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dense Spray Structure and Phenomena written by R. N. Parthasarathy and published by . This book was released on 1986 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes theoretical and experimental study of dense sprays. The work was divided into two phases: (1) an investigation of particle laden water jets; and (2) an investigation of large scale liquid jet in the atomization regime. The particle laden jet experiments involved nearly monodisperse glass particles in water injected into still water, to simulate phase density ratios typical of high pressure sprays. Preliminary findings suggest that the locally homogeneous flow approximation, where interphase transport rates are assumed to be infinitely fast, is more successful for this flow than was observed during earlier work with phase density ratios further from unity. This is encouraging for application of relatively simple locally homogeneous flow analysis to high-pressure combustion processes encountered in power and propulsion systems. Measurements of the atomization of the atomization of large scale liquid jets show the presence of an all liquid core which extends an appreciable distance from the injector (ca. 200 injector diameters) at atmospheric pressure conditions. The drop containing shear layer adjacent to this core exhibits some properties of a locally homogeneous flow, however, large drops were also formed at the liquid surface which probably depart from this behavior. Measurements of liquid volume fraction suggest relatively slow rates of turbulent mixing for the low pressure conditions of present experiments.
