Download or read book Effect of Flow Turbulence on Evaporation Rate of a Single Droplet written by A. V. Eckartsberg and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Droplet Evaporation in an Active Turbulence Grid Wind Tunnel written by Ferran Marti Duran and published by . This book was released on 2012 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, we develop and test an experimental apparatus capable of examining the effect of turbulence on the evaporation of droplets when the Kolmogorov scale is smaller than the size of the drop (where size refers to the nominal droplet diameter). Traveling drop and suspended drop cases have been studied experimentally and the evaporation rate has also been predicted based on classical computations of transport rates. Cases involving still air, a mean flow with turbulence, and a mean flow without turbulence have been tested. The experimental data matches the theoretical computations for the case of still air and mean flow with no turbulence. There is no accepted computational model that can account for turbulent flow, but the experimental conditions tested so far do not show any measurable effect of turbulence on the evaporation rate. These findings suggest that turbulence is a much smaller factor in evaporation than is mean flow over the droplet. Hence, one suggestion for future work is to study traveling droplets with zero relative velocity to the air in order to focus the analysis on the effects of turbulence with no mean flow.
Download or read book An Experimental Investigation of the Effect of Fuel Droplet Size on the Vaporization Process in a Turbulent Environment at Elevated Temperature and Pressure written by Cameron Mark Verwey and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance of liquid-fuelled spray combustion systems has a massive impact on the efficiency of energy production in many sectors across the globe. Realistic combustors generate sub 100-μm droplets and operate under high pressure and temperature in strong turbulence. Investigations into droplet evaporation and combustion provide fundamental knowledge and validation data regarding the behaviour of sprays, and although single droplet approaches have been a staple of energy research for many decades, there is little information regarding the effect of turbulence and initial diameter, especially micro-sized, on droplet evaporation rates. The present experimental study develops, interprets, and correlates the results of almost 500 tests performed on isolated heptane and decane droplets. Droplets in the range of 110 - 770 μm (initial diameter) were generated and suspended on small intersecting micro-fibers in a spherical fan-driven chamber and exposed to quasi-zero mean turbulence of intensity up to 1.5 m/s, temperatures ranging from 25 - 100°C, and pressures between 1 and 10 bar. The results indicate that droplet size has a major influence on evaporation rate, as measured by the temporal reduction in droplet surface area, when the environment is turbulent. Evaporation rates increased with both initial diameter and turbulence intensity at all test conditions. The effectiveness of turbulence, defined as the ability of turbulence to improve the evaporation rate over the rate of a stagnant droplet at identical ambient conditions, increased with pressure but decreased with temperature. Both the ratio of Kolmogorov length scale to droplet diameter and the theoretical molar concentration gradient of fuel at the droplet surface are found to be excellent predictors of turbulence effectiveness. Correlation approaches utilizing a turbulent Reynolds number or a vaporization Damköhler number are suggested to predict the evaporation rate of a single droplet exposed to a purely turbulent flow field.
Download or read book ENGINEERING RESEARCH INSTITUTE THE EFFECTS OF TURBULENCE AND WIND SPEED ON THE RATE OF EVAPORATION OF A FUEL SPRAY written by R.G. FLEDDERMAN, A.R. HANSON and published by . This book was released on 1951 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics of Droplets written by Arnold Frohn and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book deals with the dynamical behaviour of single droplets and regular droplet systems. It has been written mainly for experimental researchers. After a short description of the theoretical background, the different experimental facilities and methods necessary for the investigation of single droplets are described in detail. A summary of important applications is included.
Download or read book The Evaporation of Liquid Droplets in Highly Turbulent Gas Streams written by Richard Gould and published by . This book was released on 1998 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Single acetone and heptane droplets were suspended from a hypodermic needle in turbulent airflow, and the Nusselt number was obtained from direct measurements of the droplet diameter and evaporation rate. Acetone was selected because it fluoresces when irradiated with ultraviolet laser radiation while heptane was selected because of its high volatility compared with water, methanol, and ethanol which were used previously. Planar laser induced fluorescence (PLIF) measurements were made to obtain qualitative concentration measurements of gaseous acetone in the boundary layer surrounding the droplet. The goal of these measurements was to give insight as to why the evaporation rate is increased by 50 % when the gas phase turbulence is increased from the laminar flow case to the case where the freestream turbulence is 10%. The use of acetone droplets required that the influence of humidity on droplet evaporation rate be considered. Measurements of the turbulence intensity of heated freestream air were also made. Finally, many modifications to improve the experimental apparatus were made during this research project.
Download or read book On the Evaporation Rate of Single Fuel Droplets Due to Isotropic Ambient Turbulence written by J.-S. Wu and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Droplets and Sprays Simple Models of Complex Processes written by Sergei S. Sazhin and published by Springer Nature. This book was released on 2022-06-28 with total page 603 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book acts as a guide to simple models that describe some of the complex fluid dynamics, heat/mass transfer and combustion processes in droplets and sprays. Attention is focused mainly on the use of classical hydrodynamics, and a combination of kinetic and hydrodynamic models, to analyse the heating and evaporation of mono- and multi-component droplets. The models were developed for cases when small and large numbers of components are present in droplets. Some of these models are used for the prediction of time to puffing/micro-explosion of composite water/fuel droplets — processes that are widely used in combustion devices to stimulate disintegration of relatively large droplets into smaller ones. The predictions of numerical codes based on these models are validated against experimental results where possible. In most of the models, droplets are assumed to be spherical; some preliminary results of the generalisation of these models to the case of non-spherical droplets, approximating them as spheroids, are presented.
Download or read book 35th AIAA Thermophysics Conference written by and published by . This book was released on 2001 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book WADC Technical Report written by United States. Wright Air Development Division and published by . This book was released on 1956 with total page 1746 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Turbulence on Droplet Evaporation and Drag written by Carlos Pereira Salvador and published by . This book was released on 2000 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multiphase Flow Handbook Second Edition written by Efstathios Michaelides and published by CRC Press. This book was released on 2016-10-26 with total page 1559 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Multiphase Flow Handbook, Second Edition is a thoroughly updated and reorganized revision of the late Clayton Crowe’s work, and provides a detailed look at the basic concepts and the wide range of applications in this important area of thermal/fluids engineering. Revised by the new editors, Efstathios E. (Stathis) Michaelides and John D. Schwarzkopf, the new Second Edition begins with two chapters covering fundamental concepts and methods that pertain to all the types and applications of multiphase flow. The remaining chapters cover the applications and engineering systems that are relevant to all the types of multiphase flow and heat transfer. The twenty-one chapters and several sections of the book include the basic science as well as the contemporary engineering and technological applications of multiphase flow in a comprehensive way that is easy to follow and be understood. The editors created a common set of nomenclature that is used throughout the book, allowing readers to easily compare fundamental theory with currently developing concepts and applications. With contributed chapters from sixty-two leading experts around the world, the Multiphase Flow Handbook, Second Edition is an essential reference for all researchers, academics and engineers working with complex thermal and fluid systems.
Download or read book Direct and Large Eddy Simulation VII written by Vincenzo Armenio and published by Springer Science & Business Media. This book was released on 2010-04-28 with total page 575 pages. Available in PDF, EPUB and Kindle. Book excerpt: After Surrey in 1994, Grenoble in 1996, Cambridge in 1999, Enschede in 2001, Munich in 2003 and Poiters in 2005, the 7th Workshop, DLES7, will be held in Trieste, again under the auspices of ERCOFTAC. Following the spirit of the series, the goal of this latest workshop is to establish a state-of-the-art of DNS and LES techniques for the computation and modeling of transitional/turbulent flows covering a broad scope of topics such as aerodynamics, acoustics, combustion, multiphase flows, environment, geophysics and bio-medical applications. This gathering of specialists in the field should once again be a unique opportunity for discussions about the more recent advances in the prediction, understanding and control of turbulent flows in academic or industrial situations.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Flow and Heat and Mass Transfer in Laminar and Turbulent Mist Gas Droplets Stream over a Flat Plate written by Victor I. Terekhov and published by Springer. This book was released on 2014-07-08 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book the author presents selected challenges of thermal-hydraulics modeling of two-phase flows in minichannels with change of phase. These encompass the common modeling of flow boiling and flow condensation using the same expression. Approaches to model these two respective cases show, however, that experimental data show different results to those obtained by methods of calculation of heat transfer coefficient for respective cases. Partially that can be devoted to the fact that there are non-adiabatic effects present in both types of phase change phenomena which modify the pressure drop due to friction, responsible for appropriate modelling. The modification of interface shear stresses between flow boiling and flow condensation in case of annular flow structure may be considered through incorporation of the so called blowing parameter, which differentiates between these two modes of heat transfer. On the other hand, in case of bubbly flows, the generation of bubbles also modifies the friction pressure drop by the influence of heat flux. Presented are also the results of a peculiar M-shape distribution of heat transfer coefficient specific to flow boiling in minichannels. Finally, some attention is devoted to mathematical modeling of dryout phenomena. A five equation model enabling determination of the dryout location is presented, where the mass balance equations for liquid film, droplets and gas are supplemented by momentum equations for liquid film and two-phase core.
Download or read book Droplet Vaporization in Turbulent Flow written by Jung-Kyu Park and published by . This book was released on 1987 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt:
